Allergies are the body's exuberant response to something that's actually harmless, and really anything that the body gets exposed to can cause an allergy. In terms of what people are allergic to, most commonly medications. Those can be either inhaled, ingested, or by vein. Foods are common allergens as well. You can be allergic to things that your skin comes in contact with, as well as aero allergens, which are allergens that are in the environment, most commonly thought of as pollens during the growing seasons, or cat dander, dust mites, mold. Stinging insects can cause allergies as well.
The symptoms are going to depend on what part of the body is getting exposed. If your skin is getting exposed to an allergen, the most common symptom is going to be a rash. You can get a rash that looks more like eczema, or poison ivy, or rashes like hives. If you're breathing in an allergen, then the most common symptoms are going to be nasal, so runny, itchy nose, congestion, sneezing, post-nasal drip. Allergens that are coming in through the nose can also affect the lungs, and can flare underlying conditions like asthma or COPD. In terms of the eyes, they're very exposed to aero allergens, and so itchy, watery eyes are common symptoms when exposed to allergens in the environment. And then when allergens are getting inside the body, such as food or drink, medications, then the symptoms can range anywhere from hives or rash all the way to anaphylaxis, where the whole body gets involved, or at least more than one body system. And those reactions can be very serious and even life threatening.
Most important thing is actually going to be the clinical history. The clues that the patient gives a physician about what happened, when did it happen, has it happened more than once, and in what context. That's really where we oftentimes make our diagnosis. And then that clinical history guides us to testing in order to confirm. So the major test that we use in allergy is going to be skin testing, where a little drop is put on the skin and poked through. And then blood testing, where we look for the IgE antibody against a specific allergen. There's also intradermal testing, where some allergen is injected under the skin, and so that has a little bit of a higher sensitivity in terms of picking up maybe more subtle allergies. And tests are available, blood tests and skin tests, for all the different kind of allergens we look at. The only thing that doesn't have validated testing is going to be drug allergy, except for penicillin.
The first step is going to be helping to identify what somebody is allergic to. And then once we identify, we talk about different ways to avoid that item. There are ways to make somebody temporarily unallergic, if you're talking about a drug allergy, and then they can get through a course of a medication. We can also do allergy shots for environmental allergens. And then in experimental phase right now is a desensitization for foods. And so by gradually increasing the amount of food that's ingested, patients can then tolerate food allergens. If somebody cannot avoid it and we cannot make them temporarily or permanently unallergic, then we usually try to treat the symptoms. So depending on where the symptom is, the treatment will vary, but trying to really make patients as comfortable as possible with allergens that they're not able to avoid.