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Q. I’m Canadian, and while on holiday in Ecuador, I ate fish in a restaurant for lunch. I don’t know what kind of fish it was, but within minutes of eating it, I felt very nauseous. I stopped eating, but continued to feel worse. I got very dizzy and could not stand up, and I broke out into extreme perspiration all over my body, even though it was a cool day. When I was able, I returned to my hotel and slept for several hours. I love eating fish (though I avoid shell fish) and have never had anything like this happen. Could this have been an allergic reaction? Was it related to eating a kind of fish I’m not accustomed to?

A. Based on the description you provided, it sounds as though your symptoms may have been a toxic reaction to the fish you consumed, rather than a true allergic reaction.  One food borne illness related to fish is called scromboid poisoning, or histamine toxicity. Scromboid poisoning is related to the decay of histidine, an amino acid that exists naturally in fish, converting over time at warm temperatures to histamine. Histamine is the natural chemical responsible for allergic reactions. 

Scromboid poisoning typically begins within 5 to 30 minutes after eating spoiled fish, although sometimes it can be delayed for as long as two hours. It can resemble an allergic reaction, often starting with GI symptoms, such as nausea; followed by neurologic symptoms, such as dizziness. Symptoms are generally self-limited, but may last for several hours.

You also mentioned that you avoid shellfish. Is this due to a previous history of a shellfish reaction? If so, your allergist can perform testing to confirm or refute a shellfish allergy and help you manage and avoid future reactions.  Your allergist can also evaluate your recent adverse symptoms to the fish you consumed in Ecuador further.  

Q. Is it possible for a shellfish allergy to go away? I developed an allergy to shrimp and lobster in my 20s. Now I'm 65, and I'm wondering if there is a chance the allergy will ever go away.

A. Although many children outgrow allergies to milk and egg, it is unusual for people to “outgrow” shellfish allergy. An evaluation with your allergist would be helpful to assess your history and provide individualized recommendations for you. In the interim, you should continue to avoid shellfish. 

Q. Can eating too much peanut butter give you an allergy?

A. No, thankfully there is no relationship between consuming large quantities of a food and the development of a food allergy. If there were, a lot more people would be allergic to pizza! Eating a food is actually one way that we maintain the body’s tolerance to the food. The mechanism for how we develop allergies to foods that we have tolerated in the past is still not clear. Allergy to food can develop at any time in a person’s life, but it most commonly occurs in childhood and less commonly as an adult.

Q. My 12-year-old son suffers from sinusitis and allergies to pollen, grass and fabric softener. He had boiled eggs for lunch today and 15 minutes later had hives over his entire body, including his genitals and the bottoms of his feet, and his lips and eyes swelled up. The hives only seem to last a few hours, but they itch and seem to spread. I took him to the clinic immediately after school, where he was prescribed Allergex and Paracetamol. He has been eating eggs all his life and has never had any reaction to them before. What can we do to ease the itching of his hives? Should he avoid eggs in the future?

A. It's good that you took your son to be evaluated immediately and that he is improving.

Your son’s hives and swelling are also called urticaria and angioedema.  Hives are itchy pink or pale swellings that appear as welts, and can occur on any part of the skin.  Each individual hive typically lasts minutes to hours before fading away without leaving a mark.  New hives can arise as old ones fade away.  They can vary in size from a few millimeters to inches, and can blend together to form larger swellings. 

Hives result from blood plasma leaking through small gaps between the cells lining small blood vessels in the skin.  Histamine is a natural chemical released from allergy cells, which lie along the blood vessels in the skin.  Histamine causes the itching, swelling, and red color of hives.  The angioedema, or swelling of the deeper layer of skin, occurs through a similar mechanism.  With generalized urticaria and angioedema, topical treatments do not tend to improve symptoms; oral antihistamines are frequently needed.

Food allergy is one of the most common causes of acute hives.  Egg are a very common food allergen for children.

Your son should be evaluated by his allergist for his recent symptoms.  In his case, the cause of his reaction may have been the egg ingestion, or another ingestion that he may not have recalled immediately.  Insect stings and medications are other common triggers for acute urticaria and angioedema. 

Your allergist will likely perform testing, which could include skin prick testing and/or blood testing to various suspected allergens.  Once the allergen is identified, your allergist will help you decide what avoidance measures to take.

Because you suspect egg, avoidance of egg until your son sees his allergist would be a safe and conservative strategy.

Q. I have been allergic to “nuts” my whole life, but as I have grown older, have realized various distinguishable reactions to different nuts if I consume them. I have also noticed that I am allergic to some nuts, but not all – and I am really interested in discovering any relationship that may be present between each nut I am allergic to. When I eat cashews and pine nuts, I experience an “itchy” feeling inside my mouth, which also goes into my chest. I also feel like I need to throw up, but can't. When I eat macadamia nuts, however, I experience extreme swelling inside my mouth, verging on anaphylaxis. I have never consumed large amounts of any of the above-mentioned nuts, but I am sure that if I did, I would have an anaphylactic reaction. The reaction following consumption of the above nuts is nearly immediate, so I am usually able to detect the sensation fairly quickly and refrain from consuming any more. From my brief research, I have discovered that cashews and pine nuts are not actually considered nuts. I would like to know if you are aware of any similarities between each of the 3 nuts above, so I am able to pinpoint what it actually is that I am allergic to.

A. Being allergic to tree nuts is becoming more common.  When a person is allergic to one tree nut they may not necessarily be allergic to all other tree nuts.  Patients with cashew allergy may develop adverse reactions to other items such as pistachios, mangoes, and poison ivy.  Pine nuts have been reported to cross react with mugwort, wormwood, and sagebrush.  Interestingly, macadamia nuts have allergenic proteins that cross react with hazelnuts (filberts).

Q. Will a nursing baby whose mom eats eggs have an allergic reaction to the eggs?

A. It has been clearly demonstrated that intact food allergens can be passed through breast milk and cause allergic reactions, particularly eczema in food allergic infants. Mothers should avoid ingesting those foods that trigger allergic reactions in their infants during or after breastfeeding.

Q. A few days ago I ate one piece of watermelon and my whole throat started feeling itchy and puffy. The same thing happens with cucumber, kiwi fruit, avocado, and bananas. What might be the cause of this?

A. Based on the history you provided, it sounds like you may have a condition called “oral allergy syndrome,” sometimes also called pollen-food sensitivity syndrome.  Oral allergy syndrome is caused by an allergy to cross-reacting proteins found in pollens and in the foods you described. Many of these proteins are heat, acid, and enzyme labile; meaning that when you eat the food, they can cause your mouth to itch but the acid and enzymes in your digestive system break them down before your body can absorb them.  For this reason, oral allergy syndrome is rarely associated with symptoms beyond the oral cavity such as hives, breathing difficulty, or anaphylaxis. In many cases, heating the foods will denature the proteins. For example, a cake baked with banana may not cause symptoms in some patients who have symptoms with fresh bananas.

The treatment for the oral allergy syndrome is to avoid the foods that make your mouth itch. Some foods, such as apples and melons, store their proteins in the peel or rind, so removing the outside part can help. Finding alternative fruits and vegetables that do not cause symptoms is recommended.  Your allergist will help to guide your evaluation and provide you with personalized recommendations.  

Q. I can eat soy products (i.e., soy sauce), but when I try to drink soy milk, I experience an itch in my mouth (usually after a couple minutes). Should I stop drinking soy milk?

A. Based on the history you provided, it sounds like you can tolerate some soy products, but not soy milk. The answer to whether you should permanently stop drinking soy milk depends on a number of variables, including the amount of soy milk needed to cause the reaction, the consistency of your symptoms with soy milk, whether other foods are involved, and whether you have other accompanying symptoms beyond oral itching.  

If you only have oral itching with no other associated symptoms, then you may have what is called “oral allergy syndrome.”  Oral allergy syndrome manifests as isolated oral itching due to a food protein (such as soy) that cross reacts with the protein in a pollen (such as birch pollen).

The best way to find out if your symptoms are being caused by oral allergy syndrome is see an allergist, who will go over your history in detail and consider allergy testing to pollens and/or soy.

As soy is a common food in many diets, knowing which foods to avoid would help you manage your symptoms.  In the meantime, conservative avoidance of soy, until you have an appointment with your allergist, is the safest course of action. 

Q. Is it possible to develop a tree nut allergy at 43? If so, why, and is there hope of reversing it?

A. It is possible to develop a tree nut allergy as an adult.  Most food allergies start in childhood, but they can also develop in adults. It is unknown why some adults develop an allergy to a food they have previously consumed without problems.

Tree nut allergies are common in both children and adults. Approximately 9% of children with a tree nut allergy eventually outgrow their tree nut allergy.  In an adult, “outgrowing” or “reversing” a tree nut allergy is not common. 

Tree nuts can cause severe, potentially fatal, allergic reactions.  To prevent an allergic reaction, strict avoidance of tree nuts is essential.   A person with an allergy to one type of tree nut has a greater chance of also being allergic to other tree nuts.  Therefore, many experts advise patients with an allergy to a tree nut to avoid all tree nuts.  Your allergist can help you with personalized recommendations for your care. The Food Allergy Research & Education (FARE) website is also an excellent resource.

Q. Is it safe for a science class to plant peanuts when a child in that class is allergic to peanuts? Even if the child is separated during the planting portion, wouldn't the risk of them contaminating the class be too hazardous?

A. As long as the child doesn’t eat the peanut and washes her/his hands after contact with the peanut shell, the risk of an allergic reaction would be extremely low.

However, this situation may impose a risk if the child has reacted previously from exposure to raw peanut in the shell by inhalation or touch. In addition, having peanuts in the classroom may raise concerns among parents, and the project may be perceived as being insensitive to the child. As such, we do not recommend planting peanut shells as part of a school project.

Q. I'm planning to make fried chicken using peanut oil. I recently read that peanut oil doesn't cause peanut allergy reactions. Is that true? Is there something on the label of the oil or the packaging that will let me know that?

A. Most individuals with peanut allergy can safely eat highly refined peanut oil. This is not the case, however, for cold-pressed, expelled, extruded peanut oils. If you are allergic to peanuts, ask your allergist whether you should avoid peanut oil. For more information, the Food Allergy Research & Education (FARE) website is also an excellent resource.


Q. I am allergic to the protein in milk, but when I went to see an allergist, all he told me was to stop drinking milk or any dairy products. Is there anything else I can do? Medicine? Something else?

A. Unfortunately, avoidance of the food allergen is the only way to protect against an allergic reaction to a food at this time.

However, there is good news. Clinical trials of promising new treatments are underway. Trials including sublingual immunotherapy, oral immunotherapy, and herbal formulas are being conducted at major medical centers nationwide. There may be additional therapies for management of food allergies in the future.

Q. I have several food allergies: Most severe - sesame and peanuts; moderate - honey dew, cantaloupe, watermelon, wheat, rye, barley and hops; mild - corn, preservatives. I know that I am not allergic to tree nuts, but to avoid cross contamination, my doctor said to avoid them. But what about different seeds? I know that sunflower and sesame are from the same family. Does this indicate that I should avoid sunflower seeds and other seeds? My goal is to make gluten-free seed crackers or granola.

A. Although many seeds share common proteins, there is limited data on whether these common proteins cause clinical cross-reactivity in patients. There is a published report of three patients who had allergic reactions to poppy seeds, and who also had positive allergy testing to sesame seed.

Serum and skin tests are available to many seeds. In a case such as yours, given your multiple sensitivities, I recommend you follow-up with your allergist to discuss a plan of care. Options may include testing and potential oral challenge(s) to the seed(s) you wish to introduce to your diet.

Q. Is it possible to be allergic to a dye in a food?

A. There are many additives used by food industries. Many people tolerate dyes in foods without incident. Unfortunately, some people do have adverse symptoms related to dyes. Reactions to dyes are sometimes suspected in patients who have symptoms with apparently unrelated foods; or to a certain food when prepared outside of the home, but not homemade.

Evaluation of adverse reactions to dyes can be very challenging, as there are limited testing strategies available for many dyes.

You should discuss your history of symptoms, foods consumed around the time of symptoms, and foods that you are known to tolerate with your allergist. Knowing the ingredients of foods that you tolerate, and ingredients of foods that you have had trouble with can help to focus the search for your specific triggers.

Q. My son recently had an allergic reaction to peanut butter, causing immediate wheezing and requiring a visit to our local ED, so his primary care physician ordered some allergy blood tests. The tests showed that my son is allergic to peanuts, but also to wheat and milk. I was told I need to remove peanut, milk and wheat from his diet. Currently he eats wheat and drinks milk every day without any trouble. Do I really need to take these foods out of his diet? Will I harm him if I don t?

A. Your son should definitely continue to strictly avoid all foods containing peanut and maintain two epinephrine auto-injectors at all times.

The good news is that he does NOT have to remove milk or wheat from his diet if he is able to eat these foods without symptoms. While food allergy is becoming more common, so is the over-diagnosis of food allergy. Your doctor likely ordered a test looking for allergic antibodies, called IgE, to a panel of foods. Another test that can be done to aid in the diagnosis of food allergy is allergy skin prick testing. It is very important to know that patients can have a positive blood or skin test to a food, however, without having an allergy to that food (i.e. false positive). A diagnosis of food allergy is best made when someone has both a positive allergy test to a specific food and a history of reactions that suggests an allergy to the same food. The gold-standard, or best test, to diagnose food allergy is an oral food challenge performed by an allergist. Your son's positive blood test to peanut, paired with his recent reaction, confirms peanut allergy, but positive blood tests alone do not indicate food allergy.

Sometimes providers order another type of antibody test to foods, called IgG, to foods. This unproven test does not ever indicate allergy and can lead to inappropriate diagnosis and unnecessary food avoidance diets. If you think your child may have a food allergy, or if you have limited your diet based upon possible food allergies, I suggest you consult with an allergist. Allergists are pediatricians or internal medicine doctors who have completed two to three additional years of specialty training on diagnosing and treating allergic conditions.

Q. Is celiac disease the same as a wheat allergy?

A. Celiac disease (also called celiac sprue) is caused by an abnormal immune reaction to gluten in the small intestine. Gluten is a protein found in various grains. When individuals with celiac disease eat gluten-containing products such as barley, rye, and wheat, damage occurs in the lining of the small intestine. People typically experience symptoms such as abdominal pain, bloating, or diarrhea as a result, and may be at risk of malnutrition and complications such as osteoporosis and anemia. Blood tests are frequently used to identify patients with high likelihood of having celiac disease. To confirm a diagnosis of celiac disease, a biopsy of the small intestine is obtained by a GI specialist. If a patient with celiac disease eliminates gluten from the diet, the small intestine will start to heal and overall health improves. Medication is not normally required. 

In contrast, a wheat allergy is an overreaction of the immune system specifically to wheat protein. When a person with wheat allergy ingests wheat protein, it can trigger an allergic reaction that may result in a range of symptoms such as skin rash, itching, swelling, trouble breathing, wheezing, and loss of consciousness. Wheat allergy can be potentially fatal. Patients with wheat allergy must strictly avoid wheat, and must have quick access to epinephrine in event of an allergic emergency. Wheat allergy is most common in children. Many children outgrow wheat allergy in early childhood. Many patients with wheat allergy can consume other grains. However, some patients with wheat allergy are also allergic to other grains. You should discuss foods that can be safely consumed and foods to avoid with your allergist.

Q. Some months ago I emailed the restaurant chain Chick-fil-A, to inquire about allergens in their products.  I was specifically interested in peanut, tree nut, and sesame allergens.  I was directed to the allergen statement on their website.  Among the information regarding common allergens, they have included the statement: "Chick-fil-A uses 100% refined peanut oil for all of our breaded chicken. According to the FDA, highly refined oils such as soybean and peanut oil are not considered allergenic, and therefore are not labeled as such." Is this accurate? Are refined oils considered safe for allergic individuals and exempt from labeling requirements?

A. The statement by Chick-fil-A is accurate in that the FDA has a legal document called the Food Allergen Labeling and Consumer Protection act of 2004 (FALCPA). The document states that “Under FALCPA, raw agricultural commodities (generally fresh fruits and vegetables) are exempt [from labeling requirements] as are highly refined oils derived form one of the eight major food allergens and any ingredient derived from such highly refined oil.”

Refined peanut oil is generally considered safe for most peanut allergic persons. This is thought to be due to the fact that most, if not all, of the protein is removed during the extraction process. There have been studies into whether reactions occur in peanut-sensitized individuals with exposure to refined peanut oil versus crude peanut oil. Those who participated in one study did not have a reaction to refined peanut oil and 10% had a reaction to crude peanut oil. Other studies are conflicting, showing that a small number of peanut allergic individuals may have a reaction to refined oils.

It is not currently clear whether there is protein if any in refined oils and whether this minute amount could cause an allergic person to react, but in general, most peanut allergic persons do tolerate refined peanut oil. What we do know is that the protein content of these refined oils is consistently about one hundredfold lower then crude or cold pressed peanut oil (100-300 micrograms). Consumption of crude or cold pressed oils would not be recommended, due to the protein content in these oils.

Q. Are there any new treatments for food allergy other than avoidance?

A. Unfortunately, not at this time. Currently there are other therapies for food allergy being studied, such as oral immunotherapy, but these have not been approved yet. We anticipate in the future though, there may be other options. For now, the recommendation is for you to strictly avoid the foods that you are allergic to.

Q. If someone is allergic to olives, should olive oil also be avoided? Does the oil contain trace proteins from the olive, or just the fat?

A. Based on an extensive review of the literature, serious allergy to the olive fruit as a food has rarely been reported. There are three case reports of people who reacted to the ingestion of olive fruit, one report describing an allergy to olive fruit developing after pollen allergy shots, and one case of airway disease in an olive oil mill worker.

Skin allergic reactions - such as contact dermatitis or hives - to olive oil have been reported uncommonly.

In contrast, olive trees commonly cause seasonal allergy symptoms from inhaled olive tree pollen, something which typically occurs in specific growing regions.

A little background on the manufacture of olive oil is also in order: olives are cleaned and ground into a paste, which releases the oil, and then the paste is mixed to allow small oil drops to combine into bigger ones. The extracted olive oil is then separated from the fruit water and solids. Given this process, which is considered a "cold press" extraction, it is conceivable that the resulting olive oil could contain olive proteins. However, the infrequent reports of olive fruit or olive oil allergy might be related to the fact that the protein content of an olive itself is very low, approximately 2%. Of the patients reported in the literature having olive fruit food allergy, few were reported to have any reaction to olive oil.

In conclusion: if a person has, via skin tests and/or an oral food challenge, a certain diagnosis of an olive fruit allergy, the likelihood of olive oil allergy is low (due to the very low protein content). However, to be safest, your allergist can perform the same type of diagnostic testing can be done with olive oil.

Q. Have you ever heard of anyone who has developed hives, swelling and anaphylaxis 3-6 hours after eating certain forms of red meat? This recently happened to me after eating sausage for dinner. I ate around 6pm and awakened from my sleep with severe abdominal cramps. I thought the sausage had disagreed with my stomach. When I got up to go to the bathroom, I felt itchy, noticed my face was red and my eyes and lips were swollen, with small hives all over my body. By the time I arrived at the local emergency room, my blood pressure was very low and I was hospitalized for anaphylaxis. I have never had an allergic reaction to a food, and before this recent episode, I ate sausage on a regular basis. The doctor and nurses in the ER stated that it was quite unusual to have an allergic reaction to a food so long after eating it.

A. According to a study conducted by researchers from the University of Virginia, red meat allergies may be much more common than previously thought, and may even induce potentially life-threatening anaphylaxis in some people. This recent study suggests that as many as half of all unexplained food allergies may be attributed to a mammalian meat allergy. Mammalian meats include beef, pork and lamb. The researchers tested 3 groups of people across the Southeast United States with a history of anaphylaxis without known cause, for an immune reaction to galactose-alpha-1,3-galactose (also known as alpha-gal), a kind of sugar found in mammal meats. The study found that between 20-50% of the participants tested positive for allergy to alpha gal. 42% of those tested showed signs of meat allergy. If you think you might have such an allergy, consider being evaluated by a board certified allergist and discuss having further testing done.

Q. My daughter is food-allergic to all tree nuts. Our pecan trees are pollinating right now and she seems to be having a runny nose and coughing. Can she be allergic to this tree pollen as well, and do I need to keep the epinephrine injector close by?

A. While pecan tree pollen may share some proteins with its corresponding nut, most likely your daughter will not be allergic to that tree pollen just because she has a tree nut allergy. A cross reactivity between nut proteins and the pollen from the nut-producing tree has not been described in the literature.A person who is allergic to certain tree pollen (not typically nut-bearing trees, though) may have what is called "oral allergy syndrome" when they eat walnut in particular, and some other tree nuts. Symptoms include mouth itchiness, and nausea, and are less likely to progress to more severe symptoms - and sometimes have cough from drainage or allergic asthma- during the tree pollen season.So, the most likely possibility is that your daughter - in addition to her food allergy to tree nuts - has environmental allergies to tree pollen, but would be unlikely to need her epinephrine for this problem. Consider discussing this further with your allergist. Of course, epinephrine should always be on hand, in the event an accidental ingestion of nuts causes a severe reaction.

Q. I have an allergy to fish, but am concerned that I am missing out on the potential health benefits of eating fish. Could I take Omega-3 supplements made from fish oil?

A. The protein content in fish-derived Omega-3 fatty acid supplements is thought to be minimal, and likely denatured. A recent review did not uncover any reports of allergic reactions. In a study to answer this question, Mark et al tested 6 fish-allergic patients in 2008 to 2 different brands of fish oil supplements. All had negative skin tests and food challenges in this study (Mark BJ, Beaty AD, Slavin RG. Allergy Asthma Proc 2008; 29:528-9). However, as only 2 brands of fish oil were tested in so few people, these results should be interpreted with caution, especially if you are extremely allergic to fish. If you are very sensitive, it would be recommended to first see an allergist who could skin test you to the product, and then administer a food challenge to be absolutely certain.

Q. I had a question regarding mushroom compost that I just purchased for our vegetable garden. After adding many bags of mushroom compost to the top soil, I noticed that one of the components was peanut meal. I have a daughter with peanut allergy. I am assuming I need to shovel all the dirt out and not let her eat anything that we grow in that area. I can't find any information on this topic, and also wonder about other produce/mushrooms that may be grown in this medium. I don't think I've ever seen produce or mushrooms with a may contain peanut" label."

A. The contaminiation of soils with food ingredients is not rare in agriculture, and fortunately no reports of food reactions from the inclusion of these allergens in compost media have thus far been published. Direct contamination of the foods present in the area is, however, possible. Washing foods does not ensure the elimination of contaminating food allergens in the soil. Also boiling or roasting is not completely safe when considering heat-resistant contaminating allergens such as peanut allergens. Thus, in this case we suggest having your daughter avoid eating vegetable foods present in the field at the time of the fertilization. However, it is not necessary to avoid foods grown in this medium.

Q. My three-month-old son has tried seven different formulas in addition to me breastfeeding him, and still has severe vomiting and eczema. He has just seen an allergist, who recommends I stop breastfeeding him and switch him to Neocate or EleCare formula while she completes her workup. However, I am myself allergic to corn and am concerned because these products have corn components. My question is, if my son turns out to be allergic to corn, can he use those formulas safely?

A. The corn component in the hypoallergenic formulae is corn syrup, derived from corn starch which has been processed to remove any impurities. Thus, this corn starch does not have any corn protein in it. As far as we know, the allergy to foods is caused by a response to the protein part of the food. Reassuringly, experts in the area of food allergy who helped to answer this question have not had patients react to these formulae. Also, it is not established that children inherit the exact same allergy as their parents. For all the above reasons, the child is not expected to have an allergic reaction to the hypoallergenic formula. It is advisable that the introduction of this formula be done at the allergist office, on an oral food challenge protocol, so any side effects suspected to be due to the formula can be carefully evaluated.

Q. I am looking for guidance in regards to a peanut allergy question. I am a high school nurse who has several students with peanut allergies. Would you recommend instituting a peanut free zone , in regards to eliminating peanuts in the school cafeteria?

A. Thank you for your question. This is indeed an issue raised frequently in schools, with commercial airline carriers, and in other public venues. There is little evidence to support that peanut protein (the part of peanut responsible for causing allergic reactions) remains airborne to any significant level, making the risk of inhalation of peanut protein purely theoretical. For the majority of those peanut allergic to have a serious allergic reaction, the peanut protein would need to be ingested, either in the form of peanut-containing food or food contaminated with peanut. As such, care should be taken that the food eaten by the child does not contain peanuts and has not been prepared or served with utensils used to serve peanut-containing foods.In terms of peanut protein lingering on surfaces within the cafeteria, the allergic child would need to gather sufficient protein from a surface to either ingest or absorb via skin to cause an issue. That said, the latter (contact of peanut protein on exposed skin) would only rarely cause a systemic or generalized reaction, but could cause a local allergic rash. Accidental ingestion of peanut protein from contaminated surfaces may be of greater concern with younger children and toddlers who have frequent hand to mouth behaviors. One would expect that the degree of such exposure with older children and adolescents would be much less, and likely prevented by proper hand washing prior to eating. The same rationale would apply to the child s seat in the classroom and on the bus.Hand washing or use of hand sanitizer before and after meals promotes general hygiene and is encouraged. However, the risk of ingestion of peanut protein from another student s hand is quite low under normal circumstances.Certainly, it is important that an adolescent be trained in the use of his or her own injectable epinephrine device. It is also critical that other caretakers receive training in the event that the child is unable to self-administer at the time of reaction. If there are select personnel who are consistently present and available at the school on a daily basis, training these members ensures that someone is available to help the child in the event of a suspected reaction.

Q. My grandson has a severe peanut allergy. I want to plant some ornamental peanuts as landscape plants. They are sterile hybrids that do not produce any seeds or nuts. Will they be a problem?

A. Ornamental peanut plants (Arachis glabrata) have become popular for use as lawn ground cover. This distant perennial cousin of the common peanut, Arachis hypogaea, grows low to the ground and produces dense green foliage with small yellow flowers. Since it does not tolerate cold weather, the plant most commonly is grown in Florida and provides a hardy substitute to grasses commonly used in lawns. Its advantage over the common peanut is that it grows from rhizomes that spread underground. The peanut plant used to grow peanuts, on the other hand, produces legume pods underground that become the ground nuts that are used for food. Since the ornamental variety does not produce such pods, there is no risk that the plant would lead to an allergic reaction even if your grandson dug it up. Additionally, peanut allergens are not found in the foliage of peanut plants. Therefore, feel free to plant ornamental peanuts, enjoying the flowers and fullness of the ground cover without the worry of peanut allergic reactions.

Q. During her college year in South Carolina, my 20-year-old daughter was bitten by ticks on three separate occasions. With the most recent bite, after the tick was removed for several days she noticed local itching and a rash at the site of the bite. Recently she has developed a series of unexplained allergic reactions that always seem to start 3-5 hours after a meal. Typically, about 4 hours after eating she complains of a stomachache, itching of her skin all over, hives and swelling of her lips and tongue. One time, the mouth and tongue swelling were so severe we took her for treatment in the emergency room because we were concerned she would be unable to breathe. On that occasion, the doctors treated her with epinephrine. We pinpointed that these reactions seem to occur after eating any beef, lamb or pork but not when she avoided those foods. However, now she continues to have these reactions, hours after eating, but despite avoidance of beef, lamb and pork. We are puzzled. Are these serious reactions caused by foods or something else?

A. Based on the brief description of your daughter's medical reactions it is possible that she developed allergy to galactose-alpha-1,3-galactose (called "alpha-gal"), a carbohydrate found in beef, lamb, and pork food products. Systemic allergic reactions related to this allergy have been widely reported and can even present as anaphylaxis, a potentially life-threatening allergic reaction with difficulty breathing, decreased blood pressure, and other symptoms requiring emergency treatment and epinephrine.Strangely, this has been a problem for individuals living in the southeastern United States who have received bites from the lone star tick (Amblyomma americanum) found in this part of the country. Although not completely understood why, patients who have received bites from these ticks are at greatest risk for developing allergy to alpha gal. The alpha gal is contained in all red meats. In some cases affected patients also have delayed allergic reactions to beef or pork gelatin or even cow's milk, which may contain alpha gal. Typically with this type of allergy there is an unexpected 3 to 5 hour delay between meals and the beginning of the generalized allergic reaction. For this reason, it has been difficult for doctors and patients to make a connection with these foods. As in your daughter's case, it may not be adequate just to avoid red meat to prevent reactions. It also may be necessary to stay away from products such as beef and pork gelatin and sometimes milk products.Allergic reactions are caused by allergic antibody (IgE antibody). This unusual and complex problem is best evaluated by a board certified allergist in your area, who can perform testing for allergic antibodies to alpha gal, beef, pork and lamb. Once a diagnosis is established, strict dietary avoidance of all causative foods is effective treatment.

Q. Does the recent rise of childhood allergies, asthma and immune disorders coincide with their consumption of bottled water instead of tap water? That is, assuming our entire tap is now slightly toxic; wouldn't that prime the kids immune systems, so that they are less vulnerable?

A. The timing of your question couldn't be better, as a new study in the Annals of Allergy Asthma & Immunology looked at exposure to certain chemicals found in tap water, specifically dichlorophenols which are used for water chlorination. However, their conclusions might lead to an exact opposite answer to your question! Researchers at Albert Einstein College of Medicine in New York City used a nationally representative sample of more than 2,000 people ages 6 years and older in the National Health and Nutrition Examination Survey 2005-2006. They assessed the association between exposure to dichlorophenols and allergic sensitization measured by allergen-specific serum IgE levels after adjusting for sample weights and potential confounders. High urine levels (75th percentile and up) of dichlorophenols was associated with sensitization to foods. Keep in mind "sensitization" in this study does not equate to someone with a food allergy diagnosis per se, as this information is not available here. While no one knows for certain whether these chemicals are causing increasing food allergies seen in the United States, this research is indeed provocative.

Q. My 5-year-old daughter is allergic to wheat, egg and peanut. At my allergist's office, others are allowed to eat in the waiting room, without restrictions. My concern is that the food could get on the chairs or in the carpet and she could have a life-threatening reaction as a result. What are the risks to her, and how can I best address my concerns with her allergist?

A. Two issues exist here: 1) medical and 2) perceptual. Medically there is minimal risk to food allergic patients from casual exposure to foods as would happen if someone were eating in the waiting room. Contact with food-covered chairs and airborne food allergen does not cause a life-threatening reaction. Such exposure is part of daily life, so there is no completely avoiding it. A food has to be ingested to cause such a severe reaction. To that end, we would discourage food sharing.The general perception is that casual food exposure does pose a risk. For that reason, many offices do ban eating in the waiting room. After all, we don't permit cats to wander the halls, nor do we grow ragweed in the planters, so why permit food? The answer is that food is not an aeroallergen/airborne, so these are not causing the same level of risk. Allergic patients do expect an allergy office to be a safe haven from allergies, regardless of whether it is medically necessary.A bigger concern is the anxiety created regarding the hazards of exposure to certain foods. This anxiety can lead to psychological trauma to the child, and to problems when parents insist that schools ban certain foods, children sit at food-free tables and so on. The best way to know the risk level to your child is to have a "proximity challenge" done at the time of diagnosis. This can reduce anxiety and allow you to see the exact dangers posed by exposure to food - both to the food by air, and also by applying a small amount on the skin. Such testing is best done in an allergist's office. For those who feel uncomfortable with such testing, the allergist can also offer to have your child taken directly to an examination room on arrival so they don't have to sit in a waiting room where food is being consumed.Bottom line: it is easy to ban all eating. It is much harder to address the underlying anxiety that leads to the concern. The best outcome for all is to deal with that directly, by doing appropriate testing in an allergist's office.

Q. I am a 44-year-old man with a known shellfish allergy for more than 20 years.

A. I have always been told that due to my severe reaction to shellfish I was also allergic to iodine. Now, I need to have a procedure that requires injecting me with an intravenous iodine-based contrast, and I told my doctor that I am hesitant to have this procedure due to my shellfish allergy. My doctor has tried to assure me that my shellfish allergy has nothing to do with me being allergic to iodine. What is your opinion? Years ago doctors believed that shellfish allergy stemmed from increased amounts of iodine present in the shellfish, so patients with a shellfish allergy were told to avoid iodine. But we now know that having a reaction to an iodine-based contrast dye is not at all the same as an allergy to shellfish.If you are allergic to shellfish, specific proteins found in these foods are the allergens, not iodine. There is about a three percent chance that if you are allergic to shellfish you will have a reaction to contrast dyes, but this percentage is about the same in people with no known shellfish allergy. In other words, allergic people can react to multiple different things! If your doctor believes you need this procedure to make a definitive diagnosis, you should undergo the procedure. Ask your doctor to speak to the radiologist prior to scheduling the procedure and explain your fears. The radiologist may recommend pre- medicating you prior to the procedure, in an effort to alleviate your anxiety and any possibility of an allergic reaction.For your shellfish allergy, you should always carry a prescription epinephrine self-injector, and be comfortable with using this in the event of a reaction.

Q. Is it true that if you are allergic to poison ivy, you are also allergic to mangos?

A. Urushiol is a chemical found in the oil of mango sap. Urushiol is also found in poison ivy and poison oak. Therefore, people who have a history of reactions to poison ivy and poison oak should be cautious when handling mangoes.Contact with urushiol causes an itchy, blistering skin rash in some people, called allergic contact dermatitis. Touching mango tree leaves, bark, or the skin of mango fruit can lead to itching, red skin, hives, and blisters that typically begin 1-2 days after exposure.People who are sensitive to contact with urushiol can usually eat mango fruit without problems, because the pulp of the mango fruit does not contain urushiol.Suggestions for sensitive people include:

Q. Sometimes my mouth tingles when I eat melons - is this a food allergy? And could these symptoms become more dangerous?

A. You are describing a kind of allergy called oral allergy syndrome (also called food-pollen allergy syndrome), tied to the fact that some fruit and vegetable proteins are genetic cousins to certain pollens, like ragweed. So people allergic to pollen may experience symptoms when they eat related foods - such as cantaloupe or watermelon with ragweed allergy, or apples or carrots with birch tree - especially during the pollen seasons.The most common symptom of this disorder is a little tingling of the lips or itching in the mouth. Fortunately, most of the time it doesn't go beyond an annoyance. Unlike proteins in peanut or shrimp, known to cause serious allergic reactions, these fruit and vegetable proteins break down quickly when exposed to enzymes in your mouth or stomach so they are unlikely to be absorbed into your bloodstream and cause a more generalized reaction. There are reports that the severity could increase, but is it common? No.As with all allergy symptoms, however, I would advice someone who experiences these symptoms to see an allergist. An allergist can help you predict which additional foods might potentially cause problems, based on pollen skin test results. Because they break down quickly, oral allergy food proteins are not often detected in standard food allergy skin tests. But if you take the fresh fruit to the appointment and do a skin test with that, it may be positive.

Q. My daughter gets hives and has trouble breathing with even the slightest amount of peanut. Her allergy was recently confirmed by allergy testing. I am pregnant and am avoiding eating all peanut products as I've been told this can decrease the chance of my newborn developing this allergy. Is this true? What other foods should I avoid during pregnancy?

A. Recent data has found that maternal avoidance of allergens during pregnancy does not affect the risk of development of allergy. Avoiding certain foods during breast feeding may reduce eczema, possibly. Also for infants with a family history of allergy, it is recommended to exclusively breast feed for 4 months and avoid solids until your infant is at least 4-6 months of age, to decrease the risk of eczema and cow's milk allergy. For infants not exclusively breast-fed, extensively (Nutramigen, Pregestimil) or partially 'hydrolyzed' formulas in the first few months, are better than whole protein milk or soy formula. After 4-6 months, specific allergy avoidance doesn't affect development of allergy.

Q. I work in a preschool where there is a child with a history of an anaphylactic allergy to eggs. Given this child s allergy, our preschool has decided to ban other children from bringing any food containing eggs. However, there are times when the other children might bring baked goods with eggs in the ingredient list. We clean all of the eating surfaces after every meal. Would this child s egg allergy worsen with exposure to other children eating baked goods containing egg? Are we doing the right things to protect this child, and at the same time, are all of our precautions necessary?

A. While it is not uncommon for children to be allergic to hen s egg, it is unlikely that casual exposure as you described would cause a reaction. In most cases it is necessary for someone to actually eat egg protein to have a reaction. If the mother of this child insists that such exposure would place her child at risk, I would ask that the child be evaluated by an allergist who can determine precisely how sensitive the child actually is. This would most likely require either an oral challenge with egg, or at the very least a proximity challenge in which the child is exposed to egg on a surface, in the air or whatever other exposure the mother is concerned about. Without that information it is impossible to accommodate her concerns or the child s health issue.

Q. I am a school nurse and have benn asked if cross contamination can occur from board games for children with food/skin allergens. The school's parent-teacher organization is questioning if they should provide new board games versus buying them used and/or taking donations. I am not sure how long allergens can remain on an item, hence my email to you. What would you recommend?

A. Yes, food allergens can certainly remain on objects. Skin contact by touching an object contaminated with the food may cause a reaction in the rare individual who is highly allergic. Washing the objects (in this case, games) with water & soap has been found to be sufficient. This would also apply to the hands of the players, particularly if they just ate that food. However, applying this precaution in the whole school might be unnecessary and may create phobia.