Polymorphic light eruption occurring in common variable hypogammaglobulinaemia, and resolving with intravenous immunoglobulin therapy

A 55-year-old woman with a past history of lower respiratory tract infectio ns presented with a photosensitive eruption, Polymorphic light eruption (PL E) was diagnosed on the basis of the temporal relationship to sun exposure and the diagnosis was supported by positive monochromator irradiation tests in the ultraviolet A wavelength spectrum. Investigation of the patient's i mmune status identified low levels of all immunoglobulin (Ig) subtypes cons istent with common variable hypogammaglobulinaemia. Intravenous Ig replacem ent therapy, instituted to minimize risks from bacterial infections, was co mmenced and over the ensuing months resulted in a complete resolution of th e PLE. PLE is considered to represent a type IV hypersensitivity reaction d irected against a cutaneous autoantigen induced by exposure to ultraviolet light. In PLE, nonspecific immunomodulatory mechanisms of intravenous Ig ma y be active, such as a reduction in the synthesis of cytokines and a blocka ge of the IgG Pc receptors on macrophages.