New insights about delayed allergic hypersensitivity to corticosteroids.

ABSTRACT

Corticosteroids are among the most commonly used drugs, both topically and systemically. Although unexpected and paradoxical, allergic hypersensitivity to corticosteroids is a common finding, delayed-type reactions being much more frequently encountered than the immediate-type ones. With regard to cross-reactions between corticosteroids, based on patch-test results and molecular modelling, we were recently able to simplify the previous classification into 3 different groups, i.e., Group 1 the non-methylated, most often non-halogenated molecules (Group A, D2 and budesonide), which produce most of the allergic reactions; Group 2 the halogenated molecules with a C16/C17 cis ketal/diol structure (acetonide Group B); and Group 3 the halogenated and C16-methylated molecules (Group C and D1) that only rarely produce allergy.