Delayed hypersensitivity to a corticosteroid suspension containing methylprednisolone. Two cases of conjunctival inflammation after retrobulbar injection.

Two patients with chronic iridocyclitis had a delayed hypersensitivity reaction, characterized by severe conjunctival inflammation, after retrobulbar injections with a commercial suspension of methylprednisolone acetate. Although patch test reactions to methylprednisolone at enhanced concentrations were negative, delayed hypersensitivity could be easily demonstrated by intradermal testing with this corticosteroid. Both patients also had concomitant delayed hypersensitivity to a proprietary preservative (myristyl gamma-picolinium chloride) in the commercial corticosteroid suspension, which was confirmed by intradermal testing. These observations (negative patch test reactions, positive intradermal test reactions) suggest that the route of administration may be an important determinant of antigenic hapten-protein complex formation and subsequent delayed hypersensitivity responses involving cutaneous or mucocutaneous tissue.