Bullous pemphigoid and psoriasis: does subclinical bullous pemphigoid exist?

Four cases are presented in which probable bullous pemphigoid and probable psoriasis co-existed. One case represents a simple coincidence of the two diseases. In the other three cases, the bullous lesions were transient and seemed to be induced by elements of the Goeckerman regimen. The hypothesis is presented that these three cases represent a subclinical form of bullous pemphigoid induced by the irritant effects of coal tar, ultraviolet light, the reduced barrier function of a pre-existing dermatosis, or a combination of these factors.