Patch and photopatch testing in chronic actinic dermatitis.

Photopatch tests in 47 patients with chronic actinic dermatitis (CAD) showed musk ambrette to be the only significant allergen in our standard photopatch test series. The incidence of positive patch tests to a standard series of contact allergens in this group was compared with 213 men over the age of 50 years with eczema investigated in the contact clinic. Among the photosensitive patients, there was an increased incidence of reaction to thiuram-mix (CAD 10%; controls 3%), carba mix (CAD 6%; controls 1%), nickel sulphate (CAD 6%; controls 2%) and vioform (CAD 10%; controls 0.5%). A decreased incidence of reaction to potassium dichromate (CAD 0%; controls 8%) and balsam of Peru (CAD 4%; controls 10%) was recorded.