Allergic reactions to drugs and biologic agents
J. A. Anderson and N. F. Adkinson Jr
In summary, the term adverse drug reaction is used to designate any type of
undesirable and unintended response to a drug and can be broadly classified
on the basis of either the presence or absence of an immune mechanism.
Allergic reactions (immune) constitute only 5% to 10% of adverse drug
reactions. Drug intolerance (nonimmune) constitutes the rest of these
reactions. Many of these latter reactions are mild and self-limited, and
many drug intolerances cannot be exactly characterized. Of those reactions
in which an immune mechanism has been indicated or reactions that
clinically appear to be "allergiclike," a limited number of in vivo (eg,
skin tests) or in vitro (eg, RAST, IgE-ELISA, other antibody, or
cell-mediated assays) tests have proved helpful in the diagnosis. Best
studied are adverse reactions to aspirin, penicillin, insulin, and RCM. The
principal treatment of all adverse drug reactions is to avoid the drug that
has been specifically identified as being responsible for the previous
reaction. In cases where avoidance is not possible, desensitization is an
alternative (eg, penicillin and insulin). Prophylactic treatment of
patients who had previously demonstrated a drug intolerance reaction (eg,
systemic RCM reaction) with medication--particularly type I activation--may
be helpful in some patients.
