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Q. I have red itchy bumps on my arms that look like mosquito bites (but are not), and they leave marks. Could this be an allergic reaction to something?

A. Based on your description of symptoms, you could be experiencing an allergic reaction to something in your environment; such as something you are eating, something touching your skin or something you are inhaling from the air. You should discuss your symptoms, and potential strategies for diagnosing and managing them, with your allergist.

Q. My friend has severe contact dermatitis, including intermittent fevers up to 103, from overexposure to epoxy while working in a boatyard. Could this be an allergic reaction? He has been treated by a dermatologist with steroid injections and mild antihistamines, but he is not getting better. His symptoms have been severe for several weeks. Would this be better treated by an allergist?

A. Epoxy resin can cause more than one type of allergic reaction, but a specific patient usually has only one. It would seem that your friend may be having two different types of unrelated allergic reactions. The following is a summary of some medical facts about contact dermatitis and hypersensitivity pneumonitis, which have both been reported in association with epoxy resin. Your friend should completely avoid all exposure to epoxy resin, and should schedule a consultation with an allergist to better diagnose and evaluate his symptoms. A material safety data sheet may help your friend identify potential sources of exposure.

Contact dermatitis is the most common allergic reaction to epoxy resin and tends to occur when there is skin contact with uncured epoxy resin. While bisphenol A is the main allergen, other components (e.g., epichlorohydrin, diglycidyl ether) may also cause skin irritation. After the epoxy resin hardens, curing can take up to 2 weeks. However, patients who are very sensitive can even react to “cured” products containing epoxy resin. Nitrile rubber or nitrile butyl gloves, in addition to goggles and protective clothing are recommended for avoidance. Epoxy resin is widely used for sporting goods, dental work, and vehicle parts. For patients with dermatitis related to exposure, corticosteroids and emollients are frequently used for treatment. Unfortunately, in sensitive patients, recurrence of dermatitis occurs with re-exposure to epoxy resin.

Fever is not typically seen with contact dermatitis, but can be one of the symptoms of hypersensitivity pneumonitis or inhalation fever. In both hypersensitivity pneumonitis and inhalation fever, inhaling epoxy fumes or dust results in symptoms within a few hours. Both of these diseases can start with fever, chills, malaise, nausea, headaches and myalgias (muscle pains). While inhalation fever is not associated with lung symptoms, hypersensitivity pneumonitis is associated with cough, chest tightness, and shortness of breath. Hypersensitivity pneumonitis can develop into a very serious chronic lung disease. when hypersensitivity pneumonitis is present, the allergist is likely to find abnormalities on physical exam, chest x-ray, labs, and pulmonary function studies. If either of these two conditions are diagnosed, the patient should strictly avoid exposure to epoxy resin.

Q. I had a serious allergic reaction to mango, and the skin on my face is red, itching, and pimply. I was given medication to relieve the allergy, and have been taking it for two days, but my skin is still red, dry, and burning. Can I apply lotion or cream to help calm my skin?

A. Allergic contact dermatitis to mango is a serious problem for some people.  The skin of mangoes contains a chemical called urushiol, which is actually the same allergen found in poison ivy and similar plants (poison oak, poison sumac).  Unfortunately, once the reaction has progressed to the point of causing blisters, topical medications are not always helpful.  Oatmeal baths and using a cool, wet compress may help to soothe your skin. 

If the rash continues, you should see your allergist, as it is possible to develop a secondary skin infection due to the irritation and skin breakdown from the allergic reaction.  

Q. I have a reaction to sunscreen. I can put it on indoors and I'm fine. But the moment I step outside for 30 minutes or more, I get red and swollen, and then itchy bumps form. This lasts for several days after use, so now I don’t use any sunscreen. I've tried most of the sensitive brands, too. Am I just out of luck?

A. It sounds as if you are experiencing a photo-allergic reaction or photocontact dermatitis, meaning that the sunscreen product in combination with UVA/B rays causes you develop an allergic reaction.  Oxybenzone (benzophenone-3), the most widely used UVA blocking agent, is the most common cause of sunscreen-induced photo-allergic contact dermatitis. Other sunscreen agents known to induce photo-allergic reactions are the benzophenones, cinnamates, and dibenzoylmethanes.

Titanium dioxide and zinc oxide are inorganic filters which have excellent coverage for UVA1, UVA2 and UVB. I would suggest either one or a combination of these agents, as they will offer broad-spectrum protection with minimal irritation, sensitization, and skin penetration. Look for ones with the fewest added ingredients. Try to avoid fragrances. Although rarely used these days, always avoid PABA-containing products. 

Belly Buttons & Babies Sunscreen Lotion (SPF30) and Honest Mineral Sunscreen Spray (SPF30) both appear to fit the recommended criteria above, though I can’t specifically recommend either, as I have no personal experience with them.

You might also consider clothing products and hats that offer sun protection.

Your allergist can help with personalized recommendations and strategies.

Q. Can hives appear around the ankle or feet area?

A. Yes.  Hives (or urticaria) 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.

Q. Wherever my skin touches itself, I break out in an itchy red rash. It happens on my underarms, under my breasts, on my legs if I sleep without bottoms, in the crease of my arms if bent together for a while, etc. What is causing this and what should I do to relieve it?

A. These symptoms may be due to a condition known as dermatographism, a form of physically-induced hives. In patients with dermatographism, superficial pressure applied to the skin triggers release of histamine from mast cells in the skin. This condition may affect up to 5% of the general population. Once released, histamine causes immediate itching as well as wheals (localized hives) and redness. Dermatographism tends to be a chronic condition that can last for months or years. In many cases symptoms can be prevented by taking a non-sedating antihistamine on a daily basis.  

Q. I'm 16 years old and live in Branson, Missouri. I seem to get hives around the same time each year, though I haven't changed anything in my life. Last year, it began around the end of August/early September and they were gone by May/June. This year, it has happened again. The hives are around my underwear line, my back, and my sides. The hives are raised and are no bigger than a quarter. As the weather gets colder, they worsen. Why am I getting these hives?

A. From your description of your symptoms, it sounds like you may be struggling with cold urticaria. In patients with cold urticaria, hives develop after being exposed to cold temperatures, and contact with cold objects.  Cold urticaria can be a primary condition or related to an underlying medical condition. Some patients with cold urticaria have a family history of cold urticaria.  

Unfortunately, for many cases of cold urticaria, a cause cannot be determined.

Your allergist will likely do some testing, to include possibly placing a cold object on a portion of your skin.  Additional studies may be indicated, based on your personal and family history.

Avoidance of cold exposures and non-sedating anti-H1 antihistamines are generally the first treatments for cold urticaria. If these strategies are ineffective, higher antihistamine dosages may be tried, or other agents may be attempted.  You should discuss your symptoms, an evaluation tailored to you, and potential strategies for managing symptoms with your allergist.

Q. I am 11 years old, and whenever I get a mosquito bite, it either swells up the length of my thigh or turns into a big blister. These blisters then become black circular scars! Is this considered a severe reaction?

A. Yes, you are having a severe reaction to mosquito bites. The substances causing the reaction are the proteins in the mosquito's saliva, which they inject when they bite you.

Typically, when a person is exposed to a particular type of biting insect, they go through a series of responses. At first, there may be no reaction to the bite. After more bites, the immediate immune response begins, characterized by itching and redness shortly after a bite. Hours later, the immune response may continue and swelling could increase (called a delayed response). Eventually, a person can lose the delayed response, and ultimately even the immediate one. The timing of this series of responses is dependent on many factors - most importantly how often one is being bitten - and it may take several years to progress through all the stages to no longer being sensitive.

Some people have a more severe reaction that involves worse swelling, which may take 3-10 days to resolve. Sometimes there is bruising or blistering as you describe. Very rarely, individuals may have systemic or generalized symptoms, away from the site of the bite. This reaction has been termed Skeeter Syndrome. The good newsis that this type of reaction usually gets better over time, but the bad news is that there is no specific therapy to speed it along. The best options, then, are avoidance and treatment with antihistamines.

Avoidance includes not going to areas with a lot of mosquitoes (especially at dawn and dusk, when mosquitos are most active), using permethrin- (an insecticide available at outdoor stores) treated clothes and insect repellents like DEET (a commercially available insecticide that can be applied to skin) to keep mosquitoes away from you.

If you are bitten, a long acting antihistamine like cetirizine, fexofenadine or loratadine may minimize the reaction. These are all available over the counter. One word of caution: scratching can cause the skin around the bite area to become infected. Skin infection causes the area to be red, swollen, warm and painful. This can look just like the large local reaction you describe, but typically occurs later after the bite. If your reaction seems delayed, or if it keeps getting worse after a few days, then you should see your doctor to check for the possibility of infection.

Q. Is it possible to be allergic to sunscreen?

A. Yes, it is indeed possible to be allergic to sunscreen! Sunscreens have been associated with both allergic contact dermatitis and photoallergy, both of which require some further definition. With allergic contact dermatitis, a person typically develops an itchy skin rash only where the product is applied to the skin, and this is not unlike poison ivy, as the reaction may worsen over several days. In contact photoallergy, the reaction is due to the combination of applied substance and sunlight; therefore skin symptoms appear only once the product-laden skin is exposed to the sun. So it can be rather difficult to distinguish the exact type of allergic reaction to sunscreen, because sunscreens are applied to areas exposed to sunlight!Sunscreen allergy (from both allergic contact dermatitis and photoallergic reactions) can cause itching, blisters, red skin, and skin swelling.People may have allergic skin reactions to chemical UV absorbers or even inactive ingredients in sunscreen, such as fragrances, formaldehyde releasers, preservatives, and lanolin. If a person develops allergic skin symptoms to sunscreen, patch testing can be performed. Patch testing involves placing small patches or discs, each containing a separate chemical, on skin for a period of time. This helps identify the cause of the reaction, and can be done by an allergist or a dermatologist.Options for people who have allergic skin reactions to sunscreens include protective clothing, and sunscreen formulations that contain ingredients that scatter or reflect (rather than absorb) UV radiation. Titanium dioxide and zinc oxide are common UV blockers that have not been reported to cause allergic skin reactions such as contact dermatitis or photoallergy.

Q. Can I really be allergic to my cell phone? I have an itchy rash on my face that just won't go away. Recently, I watched a story on the news that talked about people being allergic to their cell phones, and wonder if it can actually happen?

A. Fortunately, you cannot be allergic to your cell phone per se. However, you can be allergic to metallic parts/cases of cell phones. Metals such as nickel, cobalt, and chromium are all possible causes of an allergic skin rash (called allergic contact dermatitis) from cell phone usage. A preliminary study in 2012 by Mucci and colleagues, reported at the 2012 ACAAI Annual Meeting, found nickel and cobalt in the highest concentrations in used cell phones, while an earlier study did not find high levels of nickel and cobalt in new cell phones. The higher levels in the used phones are probably due to wearing of the plastic coating on metal keys/parts occurring over time. Models that operate without keys, including the iPhone and Motorola Droid, both tested negative (keep in mind after-market cases may contain metal, however).Cellular phone dermatitis typically starts as an itchy rash on the side of the face where the phone is touched to the head, especially around the ear. People with this problem do not always report a history of known allergic reactions to metals. Allergic contact dermatitis is diagnosed based on the history and the results of patch testing to metal(s), which can be performed by your allergist. There are also several nickel and cobalt spot test kits available that allow one to test various objects for the release of nickel or cobalt ions.

Q. A middle-aged female marketing executive presents with a history of reactions twice to local anesthetics after oral surgery. She describes symptoms of transient throat tightness/shortness of breath, followed by dizziness and an episode of near loss of consciousness". Prior to the first episode, Septocaine (articaine and epinephrine) and Marcaine (bupivicaine) were given. Perioperative records indicate she felt warm and had a slight drop in blood pressure that stabilized after 10 minutes (no information on heart rate). She was sent to ED for observation, without further problem. The second episode occurred a few days later, with Septocaine given alone and a similar reaction. This time she remained supine for some time, before discharge home."

A. 4-5 yrs ago she had a reaction to a topical anesthetic gel containing lidocaine, prilocaine and tetracaine at her dentist's office. At the same visit, the dentist had injected lidocaine for anesthesia for fillings and crowns. She experienced a sensastion of throat tightness lasting 5 minutes each time after the anesthesia was placed, resolving symptoms spontaneously.Anesthetic testing was done using mepivacaine (no epinephrine). All previous reactions were to amides, which should theoretically have low cross reactivity. The mepivacaine prick test and intradermal 1:100 dilution test were negative. After subcutaneous injections of more than 1 ml were given, subsequently she reported dizziness, visibly looked pale and skin felt cool to touch. Transient shortness of breath/a sensation of difficulty breathing was noted, and she was placed supine with symptoms resolving within 2 minutes. Corresponding vitals during testing are as follows: after saline injection BP=129/75, O2 sat 100, HR 83. These changed minimally during testing, with her BP dropping to 115/72 supine and 2 minutes later, 113/71 sitting up. Fifty minutes after the first (saline) injection, her vital signs were BP=133/78, Pulse ox 100, HR 68. She did have transient hypotension (from systolic of 130 to 115 both lying supine 20 mins apart), but upon sitting up 20 mins later, this resolved.Aside from the respiratory symptoms, my impression is that she had a vasovagal reaction to explain the dizziness and transient hypotension. She required no medication for this to resolve. Since her respiratory symptoms lasted seconds and resolved upon positional change to supine, I thought she might additionally have vocal cord dysfunction. Unfortunately, this woman remains convinced she had an allergic reaction and must avoid all topical anesthetics in the future. Further, she became angered at the suggestion that she is not allergic to these medications, as she has tolerated other injections without incident.Could vocal cord dysfunction explain these transient respiratory symptoms and if so, how would you advise preventing future reactions to local anesthetic use at the dentist's office? If not VCD, what would you suspect and how would this be treated? My instinct is that this was a combination of a vasovagal reaction and basic anxiety causing a globus sensation. The reasoning: firstly, going back to her first reaction some 4-5 years ago, the procedure included both topical and injected oral anesthetics. Anyone who has ever had topical anesthetics can attest to the unsettling sensation (to varying degrees) of numbness in the general laryngeal structures. Whether or not this could this have played a role in her initial perception of a problem must be factored in to the assessment. Could this have created a mindset that has influenced subsequent reactions"? (Granted, this question is ultimately unanswerable.) The rapid resolution (within 5 minutes) without any intervention suggests a non-allergic process.Considering her more recent reactions, there was no topical anesthetic utilized, which may eliminate the local numbing sensation, unless some of the injected anesthetics leaked out of the injection site, causing a similar topical sensation. (This, however, would not have been a factor during her anesthetic skin testing.) One of the recent episodes consisted of a slight drop in blood pressure," stabilizing in 10 minutes. Two days later, a similar reaction occurred. These are more reflective of either a vasovagal or anxiety-triggered reaction. The lack of precise temporal heart rate data, however, makes the vasovagal possibility a mere clinical theory.During your skin testing, more data was available when compared to the dentist's record. Data after saline injection showed BP=129/75, Pulse ox 100, HR 83. These changed minimally during testing, with her BP dropping to 115/72 supine and 2 minutes late, 113/71 sitting up. Fifty minutes after the first (saline) injection, while presumably well, her vital signs were BP=133/78, Pulse ox 100, HR 68. With her HR dropping to its lowest point when she was well, the possibility of a vasovagal reaction is lessened, unless there was a significant time delay in obtaining vitals during the commotion of a patient in distress. This would seem to move anxiety higher up on the differential diagnosis list. The patient's pulse oximetry readings staying at 100% for most of the time (including after the saline injection) is more suggestive of hyperventilation, which can often accompany anxiety. In addition, the patient reporting dizziness, visibly looked pale and skin felt cool to touch leads one toward the possible conclusion of an anxiety reaction.Likewise, the description of dizziness and an episode of 'near loss of consciousness' fall prey to the same suspicions delineated above.I wonder about the local effects of any injected anesthetic (that may have oozed from the injection site or dripped during or after the injection) on the pharyngeal tissues, causing a numbing sensation. This can be very disconcerting, especially to a person predisposed to even a low level of anxiety, causing a globus sensation. Although this would not have been a factor during her skin testing, a learned behavior may have been put into action, causing her distress.Now as to the question of VCD involvement, VCD would likely not improve when lying supine. Rather, I believe that VCD would worsen when supine, as the pull of gravity on the anatomic structures, combined with gravitational pooling of oral secretions, would accentuate the patient's awareness of her larynx and surrounding structures. The terminology of "transient throat tightness/shortness of breath" is much too vague to be helpful and can be related to far too many causes. Differentiating inspiratory from expiratory dyspnea, along with the localization of that dyspnea, might assist in the diagnosis of VCD versus not-VCD.In order to test the waters, I would be inclined (although it might require the consent of the patient, which could mitigate the effectiveness of this methodology) to have the dentist tell the patient that, for safety purposes, he/she will be giving the next injections in a slow, graduated manner, but instead of starting with anesthetic, I would start with a couple of saline injections. If after a few minutes, the patient began to have her typical "reaction," you have your diagnosis.I actually used this method once on a patient who described throat tightening after venom IT week after week at extremely low doses. When her throat tightness occurred again, but this time, after only 0.2cc of saline, I looked at her and said, we need to talk. Fortunately, the patient was greatly relieved to know that it was not an allergic reaction to the IT, and we happily carried on with her real IT after that. It must be noted that another patient might have become angered by my test without her knowledge, so hence, involving the patient in this type of trial and obtaining a signed informed consent form would be important, especially considering this litigious environment in which we practice.Alternately, if the patient is willing, pretreating with an anxiolytic medication may be of some help. If, however, the patient is fully convinced that she is allergic to the anesthetics, there may be nothing you can do to persuade her differently. If this is the case, be prepared to possibly lose her as a patient.

Q. I have experienced hives that come and go daily all over my body during the past 6 months. I am a 32-year-old woman who has never been diagnosed with allergies or other medical conditions. Other than treatment for my hives, I take no other medications. I have changed my diet but without improvement. I was seen by an allergist who explained no cause could be identified to explain the hives, and laboratory tests were normal. My primary care doctor recommended a variety of non-sedating over the counter antihistamines, but I had no response. The constant itching is driving me crazy! Prednisone is the only drug providing relief, but hives come right back after stopping, and I don't want to stay on this! Why am I getting these hives and what can be done at this point?

A. Chronic hives, also called urticaria, affect 1% of the general population, and are seen in women twice as commonly as men. Hives persisting for 6 weeks or longer are labeled as being chronic . It is very rare to identify an underlying cause or explanation and laboratory testing rarely yields an answer.Although most people with chronic hives respond to non-sedating antihistamines, there are a variety of other anti-inflammatory medications that can be used to treat difficult cases. Additionally, some older sedating antihistamines can be helpful in some. Although prednisone, an oral steroid agent, works very well in controlling severe outbreaks of hives, it also has long-term side effects making it undesirable for chronic use. There are, however, non-steroid drugs with anti-inflammatory properties that can be used; some of these drugs, when added to daily antihistamines, have been shown improve or completely control difficult-to-treat hives. Such medications include leukotriene antagonists, hydroxychloroquine, dapsone, azulfidine, omilizumab, cyclosporine, and others. Because many of these latter agents have potential side effects, they should be prescribed by allergy or dermatology specialists with experience in treating chronic hives.

Q. I have been trying to find out the difference between atopic dermatitis and contact dermatitis. I have noticed a rash, severe at times while wearing certain clothing. It is usually around my feet and ankles. The rash goes away after removing the clothing and boots and never occurs in my normal clothing. Any information you may have will be beneficial.

A. Apples and oranges.Atopic dermatitis is a pruritic dermatitis that occurs more commonly in individuals with either a personal or family history of "hay fever", asthma or eczema. This is associated with the presence of the "allergic" antibody which is IgE.Allergic contact dermatitis has nothing to do with the "allergic antibody" but it is an immune mediated skin rash at the site of contact with a chemical allergen. An example of this type of rash would be the rash with poison ivy or the skin reaction to the nickel metal in costume jewelry in an "allergic" individual. This is medicated by sensitized T-cells and not IgE.I hope this helps. Just as apples and oranges are both fruits, atopic dermatitis and allergic contact dermatitis both affect the skin.

Q. I ve tried looking on line to no avail - just found out that I m allergic to an ingredient used in the vulcanization of rubber i.e. rain boots, the floor of the gym, the car steering wheel and a number of other things... I get the impression that latex is rubber or rubber is latex and am trying to find out:

A. Allergic reactions to rubber can be due to:1. Reaction to the natural latex is called an immediate hypersensitivity reaction manifesting as hives, rhinitis (sneezing, runny nose), asthma (wheezing, difficulty of breathing) and/or anaphylaxis (severe allergic reaction with drop of blood pressure, throat swelling). In most cases, these clinical events could be confirmed by a special blood test. Patients with this type of allergy must avoid both airborne and contact with rubber products and carry and epinephrine self injection kit.2. Allergy to one of the many chemicals used in the manufacturing of rubber. This is called a delayed hypersensitivity reaction . The natural latex sap is processed to make rubber products. The types of chemicals used in the manufacturing of rubber products such as rubber gloves include accelerators, activators, vulcanizing agents, etc. These allergies manifest as eczema or itchy rashes to the area of contact and in such instances, patch tests to various rubber mix chemicals are appropriate. Patients with this form of allergy must avoid direct contact with latex and rubber products.Very rarely some with eczema, especially the health care workers may have both types of allergies. Since there are tests for both types of allergies, they should be done (if suspected) to determine if one needs to anticipate a more severe allergic reaction to natural latex (contained in rubber products such as gloves) and carry an emergency epinephrine kit. Otherwise, people allergic to the vulcanizing agent in rubber should avoid direct contact to rubber in products such a boots. Barriers such as socks may not always work since sweating, friction, etc. may cause some leaching of the rubber to the skin. Plastic rain boots and other footwear are available. Most gym floors have hardened rubber and would not contaminate towels just by mere leaving the towel on the floor and have indirect contact with your skin. Significant direct contact is usually needed to cause a problem. Stuffing in sofa cushions are not in direct contact with the skin unless the covering has been compromised. If in doubt, a plastic barrier between the latex stuffed cushion and the covering can be done. Again, in a person with a history of contact dermatitis to rubber accelerators, direct significant contact to the rubber product should be avoided.

Q. I need some more information have had one year of terrible itching and rashes from allergies to propolis and phenolexenol, so just tossed all makeup and cleaners and got vegan goods. What else can I do?

A. Propolis is commonly used in cosmetic and medicinal preparations because of its antiseptic, antiinflammatory, and anesthetic properties. Propolis is found in a number of "natural" products, including lip balms, cosmetics, lotions and ointments, shampoos, conditioners, and toothpastes. If you tested positive to propolis (by patch test, for contact dermatitis) and your allergist/dermatologist feel that this is the cause of your itching, a list on products that are free of propolis can be obtained from the Allergic Contact Dermatitis Society (ACDS) website, by your physician. Just throwing out your old cosmetics and getting new ones (even vegan goods) does not guarantee you that the new cosmetics do not have the things you are allergic to! Chemicals may have many names and natural does not always mean it cannot cause an allergy. Remember, poison ivy is natural as well.2-Phenoxyethanol (you probably mean this instead of phenolexenol) is an antibacterial chemical and is most commonly found as a preservative in cosmetics and skin care products. Again, a list of products without this allergen (from the ACDS website) can help you avoid exposure.Here are products that may contain the chemical 2-Phenoxyethanol:

Q. I ve noticed recently that when I scratch myself I m breaking out in hives in that area! Am I allergic to myself, should I be worried? What type of treatment is available for this?

A. No you are not allergic to yourself; exposure to certain types of physical stimuli like pressure (like scratching yourself), cold, and heat can cause hives. Doctors refer to this type of skin condition, which accounts for nearly 20 percent of hives as physical urticaria (the medical term for hives). One of the most common mechanisms of physical urticarial that has been identified is dermatographism. The name of this skin condition means skin writing in Greek (derma is skin , graphe is writing ). The ability to write letters or symbols by stroking your skin (with your fingernails or a retracted ball point pen, for example), which results in blanching (whitening of your skin) that s followed by redness and swelling (hives), is the most obvious sign of this often harmless form of hives. Dermatographism affects approximately 5 percent of the U.S. population and can persist for years until the outbreaks disappear. Common triggers for dermatographism include rubbing, scratching, or stroking the skin. Tight clothing or pressure from leaning against hard surfaces (a chair or desk) can also cause this form of hives. A rarer, more severe form of dermatographism can occur following bacterial, fungal, or scabies infections, or after treating a bacterial infection with penicillin. If you feel you have any of these then you should speak to your allergist.

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

A. Mango is in the same botanical family as poison ivy. The sap of the tree and the rind of the mango fruit contain urushiol, the oil that causes the poison ivy rash. The pulp of the mango fruit does not contain urushiol, so if someone is sensitive to poison ivy, they can have someone else peel the fruit for them and then they can eat the fruit without harm. Also, it is not a good idea to fall asleep under a mango tree if you are sensitive to poison ivy.