Photosensitivity in lupus

Abstract

A wide variety of skin conditions may present in patients with lupus erythematosus (LE). These can be broadly divided into three main groups: cutaneous forms of LE (`LE-specific skin disease'), nonspecific cutaneous manifestations of SLE (`LE non-specific skin disease') and cutaneous complications of drug treatments for LE. This review examines clinical photosensitivity in LE, a trait most commonly associated with cutaneous forms of LE but which may also manifest in SLE. All humans are photosensitive, developing reddening of the skin if exposed to sufficient ultraviolet radiation (UVR). Therefore we define photosensitivity in clinical practice as an abnormal cutaneous response to UVR.

Abnormal photosensitivity in LE may manifest in a number of different forms. The lesions of LE-specific skin disease may be induced or exacerbated by UVR. Patients with LE who are prescribed photosensitizing medications such as thiazide diuretics, neuroleptics and tetracyclines may also develop phototoxic reactions which usually present as easy sunburn. Photosensitivity may also, rarely, manifest as fragile skin and blistering in patients with both LE and porphyria cutanea tarda. Several other photosensitive disorders have been reported in association with LE, including solar urticaria and erythropoetic protoporphyria (EPP), but these appear to be chance associations.

Assessment of patients with LE and photosensitivity requires a careful history and examination. Phototesting and photoprovocation tests may be used to demonstrate photosensitivity in some cases, but these are rarely required for diagnosis. Photosensitive patients should be advised about sun avoidance, photoprotection and sunscreen use as a first line treatment.