If your nose gets stuffy and your eyes start to itch every spring, you could benefit from seeing an allergist-immunologist. However, those aren't the only symptoms that might send you to this medical specialist. An allergist-immunologist is a doctor trained to diagnose and treat conditions that affect the immune system. Often these doctors are simply called allergists. However, they treat more than allergies. They can help you care for a wide range of conditions that involve your immune system. Your immune system protects your body against germs and illnesses. It helps you fight off infections by attacking harmful viruses and bacteria that invade your body. But sometimes the immune system attacks healthy cells. It can also mistake harmless things, like pollen in the air, for dangerous germs. This can cause congestion, sneezing, and itchy skin and eyes. Sometimes the immune system is too weak to do its job properly. This can make you prone to recurrent infections. Here are five reasons it might be a good idea to get advice from an allergist-immunologist. 1. If you have allergies. With allergies, the immune system overreacts to things like pollen and mold. Certain foods, medications, pets, and materials like latex or insect venom from a wasp bite can also set off symptoms. These triggers are called allergens. Coming into contact with your specific allergen causes a reaction. Contact can mean breathing it in, swallowing it, or, in the case of insects, being stung. The result is itchy eyes, a runny nose, and congestion. Sometimes serious allergic reactions develop very fast and can be life-threatening. These reactions usually affect more than one part of the body. For example, you may have a rash, trouble breathing, and nausea. This type of reaction requires immediate medical attention. An allergist-immunologist can run tests to figure out exactly what you're allergic to and how serious your allergic reaction might be. The doctor will map out an allergy action plan for you. He or she may prescribe medication to help you control allergies. Once you know what causes your allergy, you'll be better able to avoid the allergens. 2. If you have asthma. Asthma causes muscles in your airways to tighten or spasm, and can inflame the lining of your lungs. This blocks the flow of air, making it hard to breathe. Asthma can range from mild to life-threatening. You may feel tightness in your chest and struggle to catch your breath. You may also cough and wheeze. Working with an allergist-immunologist will help get your asthma under control, meaning you should have fewer flares. The doctor can prescribe medication to treat your specific symptoms. He or she can also help you learn about common asthma triggers—like smoke, mold, pet dander, and dust mites—and how to avoid them. 3. If you have a chronic sinus infection. Your sinuses are hollow openings behind your nose and around your eyes. They contain mucus to help warm and filter the air you breathe. This mucus needs to drain. If it gets blocked and your sinuses get congested, you could get a sinus infection—or sinusitis. If you have allergies, asthma, or a weakened immune system, you’re more likely to get sinus infections. An allergist-immunologist can prescribe medicines to help ease the pain and congestion of a sinus infection. You'll also learn ways to prevent a sinus infection in the first place. For instance, washing your hands often and using a humidifier or saltwater nasal spray to keep your nasal passages moist can help. 4. If you get hives. Hives are welts on your skin. Sometimes they show up and then disappear quickly without treatment. But, they can also be a reaction to a serious allergy, like an insect sting. An allergist-immunologist can run tests to look for the cause of your hives. Culprits can include certain foods, sunlight, stress, exercise, infections, and pollen. Even some medicines can cause them. Hives also could be the sign of another health problem. Sometimes, it's not possible to know for sure why you get hives. But if your doctor can identify the trigger, he or she can help you treat the condition. This often means avoiding your triggers and having an action plan in place so you know what to do if you're exposed to them by accident. 5. If you have a primary immunodeficiency disease (PIDD). PIDD is a term for hundreds of diseases linked to a problem with your immune system. If you were born with a PIDD, you have a higher risk of certain health issues, such as infections that can affect many parts of your body. PIDD also makes these infections harder to treat. An allergist-immunologist will try to find the problem in your immune system that's causing your symptoms. Then the doctor can treat it. Bone marrow or stem cell transplants, blood products, or antibiotics are possible options.