ABSTRACT
Chronic actinic dermatitis is an uncommon, sometimes disabling eczematous photosensitivity eruption affecting predominantly elderly men. The term chronic actinic dermatitis was originally proposed by Hawk and Magnus to embrace the conditions photosensitive eczema and actinic reticuloid. The exact mechanism underlying chronic actinic dermatitis remains unknown. Chronic actinic dermatitis also has been reported to develop in long-standing endogenous eczema and, rarely, long-standing polymorphous light eruption, both also postulated to be delayed-type hypersensitivity responses. Chronic actinic dermatitis affects mainly elderly men of all races, especially outdoor workers and leisure enthusiasts. The eruption gradually becomes more persistent and localized to light-exposed areas as chronic actinic dermatitis supervenes. The histologic features of chronic actinic dermatitis are generally those of epidermal spongiosis with irregular acanthosis and dermal perivascular lymphocytic infiltration. The diagnosis of chronic actinic dermatitis is suggested by the clinical findings, supported if necessary by the histologic features, and confirmed by broadband or monochromatic irradiation testing of normal skin.
