Allergic reactions are sometimes unpredictable. Always watch for a return of symptoms as medications wear off or exposure to an allergen trigger continues. Return of symptoms may be sudden and severe.

Anticipate a possible return of the reaction and a need to return to the medical office or emergency department. Use all medications only as instructed or as prescribed. Therapy to suppress an allergic reaction may involve long-acting antihistamines and other anti-allergy medications.

Severe cases may require a course of steroid treatment lasting as long as 4 weeks. Most people learn to recognize their allergy triggers; they also learn to avoid them. An allergy specialist (allergist) may be able to help you identify your triggers. Several different types of allergy tests are used to identify triggers.

Skin testing is the most widely used and the most helpful. There are several different methods, but all involve exposing the skin to small amounts of various substances and observing the reactions over time. Blood tests (RAST) generally identify IgE antibodies to specific antigens. Other tests involve eliminating certain allergens from your environment and then re-introducing them to see if a reaction occurs.

People with a history of serious or anaphylactic reactions may be prescribed an auto-injector, sometimes called a bee-sting kit. This contains a premeasured dose of epinephrine (EpiPen is one brand name). You carry this with you and inject yourself with medication immediately if you are exposed to a substance that causes you to have a severe allergic reaction.

There is some evidence that breast-fed infants are less likely to have allergies than bottle-fed infants. For typical allergic reactions, your health care provider will examine you and ask you questions about your symptoms and their timing. Blood tests and x-rays are not needed except under unusual circumstances.

In case of severe reaction, you will be evaluated quickly in the emergency department. The first step for the health care provider is to judge the severity of the allergic reaction.

The look and feel of an allergic reaction depends on the body part involved and the severity of the reaction. Some reactions affect many areas, others affect just one area. Reactions to the same allergen vary by individual.

Shock is caused by sudden dilation of many or large blood vessels. This is brought on by the action of the mediators. If the drop in blood pressure is sudden and drastic, it can lead to unconsciousness, even cardiac arrest and death.