Photosensitivity dermatitis and actinic reticuloid syndrome (chronic actinic dermatitis).

The photosensitivity dermatitis and actinic reticuloid syndrome (chronic actinic dermatitis) is a common eczematous photodermatosis of unknown aetiology that in severe form is an extremely disabling condition. It is unclear why males are particularly affected. Difficulties in diagnosis arise in patients who have perennial problems in whom clinical photosensitivity may not be volunteered. An additional problem for the clinician is the finding of contact allergy that is frequently multiple, which further complicates the clinical picture that may, in severe cases, present as an erythroderma or a pseudolymphomatous state. Patch testing and phototesting are the key investigations, with broad ultraviolet (UV) waveband sensitivity occurring as a dermatitis rather than a sunburn response. Contact allergy recognition and avoidance, along with photoprotective measures, are helpful in most cases. Photochemotherapy (PUVA) and systemic immunosuppression may be required in those patients who fail to respond. In some cases, spontaneous resolution follows after a number of years.