|MadSci Network: Immunology|
We usually think of an immune responses as being a good thing, protecting us against the flu, measles or other diseases. Some immune responses are not so beneficial and can cause discomfort or even death. Allergies are in this category and are caused by a special class of antibody called IgE. Allergies are fairly common, maybe the most familiar are the pollen allergies such as "hay fever". The symptoms are relatively mild - sneezing, runny nose, red watery eyes. Other people are allergic to certain foods, such as shellfish or peanuts, or to bee venom. The symptoms of food allergies are more severe, vomiting and diarrhea, and an allergic response to a bee sting can be fatal. The bee venom gets in the blood circulation and is distributed throughout the body, so there is a body-wide allergic reaction. This is called systemic anaphylaxis (an-ah-fi-lak-sis), and the patient can have great difficulty breathing and a dangerous drop in blood pressure. People can also become allergic to antibiotics. Streptomycin is one, although penicillin is more common since it is prescribed more often. If the antibiotic is injected, or taken by mouth and enough is absorbed into the body, the result can be systemic anaphylaxis and death. Why do some people have allergies and others do not? There are some clues, but the answer is not known and many scientists are trying to find out why.
Try the links in the MadSci Library for more information on Immunology.