Chronic actinic dermatitis

Abstract

Chronic actinic dermatitis is a persistent photodermatitis, likely resulting from a delayed hypersensitivity reaction. Older men appear to be most susceptible, and the condition leads to marked photosensitivity, with signs demonstrable after exposure to ultraviolet light even lower than the minimal erythema dose. An eczematous rash in sun-exposed sites is usual. Atypical presentations include a pseudolymphomatous appearance or erythroderma. Drug-induced photosensitivity must be ruled out. Other photosensitive conditions, including lupus and porphyria, should also be excluded. Strict photoprotection is paramount, and patients should be counselled about allergen avoidance where relevant. About 10% experience remission after 5 years. Desensitisation with PUVA or TLO1 can be useful in some cases. Topical steroids, tacrolimus or systemic agents, e.g. azathioprine, cyclosporine and mycophenolate mofetil, are other therapeutic considerations.