Spring is finally here and with it come the sneezes, coughs, runny noses, and symptoms that affect the entire body; symptoms like fever and muscle aches. We all suffer from allergies, which are immune reactions to normally innocuous environmental antigens. These foreign substances are called antigens or allergens and some examples might be pollen, mold, cat dander, dog fur, peanuts, etc. When we have a lot of rain, our gardens and lawns flourish, and our bodies are exposed to huge amounts of normally non-harmful agents. In the spring go out and run your finger along a surface and note the green stuff that you can easily lift off the surface of a lawn chair or a car hood. That’s what goes into your lungs and up your nasal passages.
Allergies are not caused by bacteria but molds and parasites are different. In the developing world parasites elicit an IgE response that can be very serious. In the developed world we are not likely to be exposed to parasites that produce such reactions. Common bread mold or mold within your air conditioner or in your heating system can sensitize you and allow you have an allergic reaction, but this is not seasonal. Sensitization is when your body is exposed to a foreign substance and you make something called IgE against it. IgE is an antibody associated with allergies. It’s a protein in the blood that is one of many classes of antibody that is part of the immune system and there to protect you. In medical classification, there are several types of allergic responses, but here we will speak of the most common one called type 1 or sudden IgE mediated reactions.
There is actually a very complex process that goes on in your body when you have an allergic reaction. There are cells in the immune system called T and B cells that are sensitized to the antigen to which you are exposed. While these reactions are caused by various mechanisms, the most common is to have an antigen bind to an antibody called IgE on mast cells, little bags of trouble that circulate around in your blood. When these cells are tickled by the offending antigen (say grass or tree dust) after binding to the IgE on the mast cell, the cells release huge amounts of histamine and other chemical substances into the blood stream and cause your reaction.
Allergic contact dermatitis is the same systemic reaction localized to the skin. Poison ivy is a good example.
IgE is something your doctor might measure in your blood because it is the typical allergic antibody or substance (immunoglobulin) attached to mast cells that makes the allergic response go forward. There are many immunoglobulins (antibodies) in the body and IgE is highly correlated with the allergic response.
Reactions vary with person to person and symptoms can vary from nasal congestion and slight fever, to the worst case, asthma. Most of the allergic reactions are minor and are nothing but annoying. The typical reaction is allergic rhinitis, which is an allergic reaction in the nasal mucosa (the nose) that causes the nasal itching, mucous production, and of course sneezing. Some patients however, find these reactions so annoying that they live on anti-histamines to work. Some people have atopy, which means that they have a genetically based tendency to have IgE reactions against innocuous substances. These people seem to develop allergies to everything. Patients who are highly allergic should avoid provocation with dietary allergens like shellfish or peanuts, because as we will see below, these agents can cause a catastrophic reaction called anaphylaxis. If one is highly allergic to something get an EpiPen from your pharmacy and carry the EpiPen around in your pocket or purse when the chance of exposure to an allergen is likely.
Asthma is quite common and can be very serious. This is basically constriction of the bronchioles of the lungs in response to local allergic events that occur within the lung itself. It is characterized by a feeling of heaviness in the chest, an inability to take a deep breath, and a loud wheezing sound. At its worst it can cause death, but that is rare. Most people simply see a doctor to obtain a bronchodilator in order to relax the bronchioles and achieve some comfort. The effects of asthma vary from individual to individual and the severity is quite apparent to most doctors who listen to your lungs, have you breathe before and after special medicine, look at something called pulse oximetry or oxygen saturation in the blood, and in some cases measure the gases in your arterial blood to see how little oxygen you have circulating.
Some allergies can be quite severe and life threatening, and anaphylaxis is an example of that. Anaphylaxis is a true emergency and happens very quickly. I have seen it in restaurants when one is allergic to foods, in baseball stadiums when someone is allergic to peanuts, or around a patient who is trying a new medicine for the first time. Anaphylaxis has a rapid onset and systemic reaction to an otherwise innocuous antigen (seafood, peanuts, bee venom, snakebite, etc.) ingested or injected. The patient suffers circulatory collapse or shock and can suffer suffocation from tracheal swelling. It is important that EMS respond to someone suspected of having anaphylaxis. This is not a patient who should be shoved into a car and driven to the hospital. EMS has the necessary drugs with which to control the severe allergic reaction and they should be called (dial 911) within seconds of suspicion that the patient is having anaphylaxis. The dispatcher should be told that this is possibly anaphylaxis and he will immediately send advanced life support to you.
Basic life support ambulances now carry EpiPens in New Jersey. An EMT is trained to help you administer the EpiPen in an emergency and she/he could save your life.
Now that spring is upon us and summer is right behind it, be aware of your surroundings. Know what to do in case of severe allergy and get your doctor to prescribe an EpiPen if you know you are extremely sensitive to certain allergens.