Some scientists believe that it may be a variation of prurigo nodularis. Actinic prurigo (AP) was first described by Escalona in Mexico, in 1954. The cause of prurigo nodularis is unknown, although other conditions may induce PN. It is sometimes considered to be a term encompassing Besnier's prurigo gestationis and other conditions. Prurigo nodularis is a related disorder showing multiple lumps. Possible associations include Hyde's prurigo nodularis and membranoproliferative glomerulonephritis. Prurigo nodularis was first described by Hyde and Montgomery in 1909. Prurigo is an itchy eruption of the skin. Actinic prurigo is a rare sunlight-induced, pruritic, papular or nodular skin eruption. Other names include "infantile eczema", "flexural eczema", "prurigo Besnier", "allergic eczema", and "neurodermatitis".