The intellectual artifact termed chronic actinic dermatitis (CAD) based on the "unifying concept" of a hypothetical endogenous photoallergen1 denies the essentially clinical nature of history taking, physical examination, and patch testing in the diagnosis and prevention of contact dermatitis. According to its creators, the conditions persistent light reactivity, photosensitive eczema, photosensitivity dermatitis, and actinic reticuloid... represent arbitrary, confusing... largely unnecessary subclassifications [and] should be considered as variants of a single condition, namely chronic actinic dermatitis.1
The significance of the term CAD was brought home to me when a case of compositae dermatitis in Australia was recently presented as CAD.2 The confusion is compounded by a report3 that sesquiterpene lactone mix is an important allergen in CAD and that contact nonphotosensitizing allergens are part of this condition called actinic.
Confusion between photosensitivity and compositae dermatitis occurs because they look the same,4 but they can be distinguished
Burry JN. Is Chronic Actinic Dermatitis a Viable Concept?. Arch Dermatol. 1997;133(3):392. doi:10.1001/archderm.1997.03890390136028