Asthma Medicines

As a rule, all patients with bronchial asthma should have an allergy evaluation. In children, allergy clearly plays a significant role in the severity of the disease and the frequency of attacks. In adults, the role of allergy is less important although most patients, when tested, are found to be allergic.

Allergy Skin Tests

Although useful as a screening test, the IgE level by itself is not sufficient to determine the presence of allergy (also called atopy). Additional evaluation may include allergy skin testing for specific substances known as allergens that may trigger asthma attacks. This method has been used for more than 100 years and represents an extremely reliable way of determining the presence of allergy to a specific substance. Skin testing is performed by pricking, scratching, or injecting the skin with a small amount of allergen. Positive reactions, which resemble hives, are noted in twenty to thirty minutes. But skin testing is time consuming and may cause total body reactions in highly sensitive individuals.

Allergy Blood Tests

Evidence for allergy may also be obtained through blood testing that detects the presence of specific antibodies to various allergens. One technique is known as RAST (Radioallergosorbent test). This test utilizes radioactive material and detects the presence of a specific IgE antibody that has been produced against a certain allergen. This method is thought to be less accurate than skin testing, however, although it may prove useful in selected individuals. Other drawbacks include greater cost when compared to skin testing as well as a delay of up to three weeks in obtaining results.

A relatively new technique known as MAST (Multiple Antigen Simultaneous Testing) has been developed for measuring allergen specific IgE antibodies. This technique is faster and less expensive than RAST and provides accurate results when compared to RAST and skin prick tests. Results may be obtained in one week.

Allergic Reaction

A positive allergy test does not always identify a significant allergy, so the patients history becomes an extremely important factor in correlating allergy test results with true triggers of asthma attacks.

Immediate and “Late” Reactions

Allergy reactions are often immediate and severe as in the patient who is allergic to bee venom, but an allergic reaction may not always be immediately apparent. Recently, it has been demonstrated that a “late phase” response may occur several hours after exposure to an offending substance. In the late phase reaction, inflammation plays a significant role, and it is essential that effective therapy be directed at this component as well as to bronchial obstruction. If not treated, this late phase reaction may form the basis of recurrent and increasingly severe asthma attacks.

Share This