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 infections presented with a photosensitive eruption. Polymorphic light eruption (PLE) 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 immune status identified low levels of all immunoglobulin (Ig) subtypes consistent with common variable hypogammaglobulinaemia. Intravenous Ig replacement therapy, instituted to minimize risks from bacterial infections, was commenced and over the ensuing months resulted in a complete resolution of the PLE. PLE is considered to represent a type IV hypersensitivity reaction directed against a cutaneous autoantigen induced by exposure to ultraviolet light. In PLE, nonspecific immunomodulatory mechanisms of intravenous Ig may be active, such as a reduction in the synthesis of cytokines and a blockage of the IgG Fc receptors on macrophages.