When your immune system is not working properly, it can lead to a variety of health problems. Some people get sick more often or take longer to recover. Others may have allergies, inflammation, or symptoms that don’t improve with regular treatment.
That’s where an immunologist (also called an allergist-immunologist) comes in. Immunologists are doctors trained to find out what is going wrong with the immune system and how to treat it. In some cases, the immune system is too weak. In others, it is too active or mistakenly attacks the body’s own healthy cells.
Below are the most common types of immune system problems and how an immunologist can help.
Primary Immunodeficiencies (PI)
Primary immunodeficiencies (PI) are conditions you are born with. Part of the immune system is missing or doesn’t work properly. People with PI tend to get a lot of infections—ones that are serious, happen often, or take a long time to go away.
Examples include:
- Common Variable Immunodeficiency (CVID): Causes repeated sinus, lung, and stomach infections due to missing antibodies.
- Severe Combined Immunodeficiency (SCID): A very serious condition that affects both T cells and B cells. Often found through newborn screening.
- X-linked Agammaglobulinemia (XLA): Affects boys and leads to very low antibody levels.
- Selective IgA Deficiency: Often mild, but can lead to infections and sometimes autoimmune problems.
Other types of PI affect different parts of the immune system, like T cells, phagocytes, or the complement system. These can cause problems like skin abscesses, poor growth, fungal infections, or bad reactions to vaccines. Special blood tests and sometimes genetic tests are needed to find the cause.
Secondary Immunodeficiencies
Secondary immunodeficiencies happen later in life. They’re not genetic, and they’re much more common—especially in adults. They usually happen because of another illness or treatment that weakens the immune system.
Common causes include:
- Chemotherapy or radiation
- Steroids or other immune-suppressing medicines
- Diabetes, kidney problems, or other long-term health issues
- HIV and other infections
- Losing protein through burns, gut, or kidney problems
People with secondary immunodeficiencies often get infections that keep coming back or take a long time to heal. Some need repeated antibiotics or hospital care.
Autoimmune Diseases
In autoimmune diseases, the immune system gets confused and attacks the body’s own cells. This can cause pain, swelling, or damage to organs.
Examples include:
- Type 1 Diabetes: The immune system destroys the cells in the pancreas that make insulin.
- Autoimmune Thyroid Disease: Includes Hashimoto’s and Graves’ disease.
- Rheumatoid Arthritis and Juvenile Arthritis: Cause joint pain and swelling.
- Autoimmune Cytopenias: The immune system attacks the blood.
- Lupus-like Problems: Sometimes seen in people with immune deficiency.
Immunologists often team up with other doctors, including rheumatologists and endocrinologists, to treat these conditions.
Immune Dysregulation Syndromes
Immune Dysregulation Syndromes are rare immune problems where the immune system can’t control itself. This can lead to long-term inflammation, autoimmunity (where the body’s immune system mistakenly attacks its own healthy tissues and organs), or out-of-control growth of immune cells.
Examples include:
- Autoimmune Lymphoproliferative Syndrome (ALPS): Causes big lymph nodes, low blood counts, and swollen organs.
- IPEX Syndrome: A genetic condition in babies that causes many autoimmune problems.
- STAT3 Mutations (like Hyper IgE Syndrome): Can cause skin rashes, infections, and autoimmunity.
- CTLA4 and LRBA Deficiencies: Can cause a mix of infection and inflammation.
- Auto inflammatory conditions.
These conditions are hard to spot, so immunologists often help when other treatments haven’t worked.
Allergic and Hypersensitivity Conditions
Because allergists are also trained immunologists, they treat immune overreactions like allergies and asthma. These happen when the body reacts strongly to things that aren’t normally harmful, like pollen, food, or pets.
Examples include:
- Asthma (especially if caused by allergies)
- Food allergies and anaphylaxis
- Eosinophilic esophagitis (EoE)
- Chronic hives or drug allergies
- Chronic rhinosinusitis with nasal polyps
- Atopic dermatitis
How an Immunologist Can Help
- Make a diagnosis. They use blood tests and sometimes genetic tests to figure out what’s wrong.
- Create a treatment plan. This could include medicine, immune therapy, or allergy shots.
- Offer long-term care. Many immune problems need regular checkups and advice about vaccines, infections, and staying healthy.
If you or your child has persistent infections, unexplained inflammation, or symptoms that haven’t responded to typical care, schedule an evaluation with a board-certified allergist-immunologist. Early intervention can make a significant difference.
Use the ACAAI’s Allergist locator tool to find a specialist near you.
See also When Should You See an Immunologist?
