Actinic prurigo (AP) is a rare acquired idiopathic photodermatosis, reported most often in American Indians, but also in Caucasian and Asian populations. The skin lesions in AP predominantly affect exposed sites but may involve covered areas, and often result in postinflammatory scarring. The diagnosis of AP can be difficult and relies on a combination of history, clinical experience and investigations including phototesting and human leucocyte antigen typing. Twenty-one patients (17 women, four men) diagnosed with AP at the photobiology clinic at St Vincent's Hospital Melbourne were reviewed in this retrospective study. The mean age of patients at presentation to the clinic was 25 years, with the mean age of onset being 14 years. Phototesting was undertaken in 20 patients, with 12 (60%) having reduced and eight (40%) normal minimal erythema doses. Human leucocyte antigen typing indicated 18 patients (85.7%) were DR4 positive, with further subtyping of the DR4 allele establishing that 15 patients (71.4%) were DRB1*0407 positive and that two (9.5%) were DRB1*0401 positive. This condition is often recalcitrant, with treatment options including photoprotection, topical and oral corticosteroids, antimalarials, phototherapy and thalidomide.

A retrospective study was performed to analyse the clinical and photobiological features and therapeutic outcomes of 44 patients with chronic actinic dermatitis who were evaluated over an 8.3-year period. The study population comprised 37 men and seven women with a mean age of 62.7 years (range 26-85 years). The most common abnormal phototest results were decreased minimal erythema doses to both UVA and -B (73.8%), and to UVA alone (14.3%). Twenty-six patients (78.8%) had at least one allergic, photoallergic or combined allergic/photoallergic reaction. A total of 139 positive contact or photocontact reactions were recorded (mean 4.2 per patient). Most commonly, treatment consisted of photoprotection, topical corticosteroids and episodic use of systemic agents, in particular azathioprine.

Actinic prurigo (AP) is a rare acquired idiopathic photodermatosis, reported most often in American Indians, but also in Caucasian and Asian populations. The skin lesions in AP predominantly affect exposed sites but may involve covered areas, and often result in postinflammatory scarring. The diagnosis of AP can be difficult and relies on a combination of history, clinical experience and investigations including phototesting and human leucocyte antigen typing. Twenty-one patients (17 women, four men) diagnosed with AP at the photobiology clinic at St Vincent's Hospital Melbourne were reviewed in this retrospective study. The mean age of patients at presentation to the clinic was 25 years, with the mean age of onset being 14 years. Phototesting was undertaken in 20 patients, with 12 (60%) having reduced and eight (40%) normal minimal erythema doses. Human leucocyte antigen typing indicated 18 patients (85.7%) were DR4 positive, with further subtyping of the DR4 allele establishing that 15 patients (71.4%) were DRB1*0407 positive and that two (9.5%) were DRB1*0401 positive. This condition is often recalcitrant, with treatment options including photoprotection, topical and oral corticosteroids, antimalarials, phototherapy and thalidomide.

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