Thoughts on irritant contact dermatitis.

An attempt is made to formulate some kind of working hypothesis concerning the pathophysiology, clinical appearance and treatment of irritant contact dermatitis. Acute irritant dermatitis may be caused by one single overwhelming external exposure of comparatively short duration. It is usually accidental and therefore recognized early as cause and effect. Chronic irritant dermatitis may be the result of a too early repetition of one impairing factor (chronic irritant dermatitis "traumiteration' type), but is more commonly the result of the influence of a variety of stimuli, each starting to be active before recovery from the foregoing stimuli has been completed (chronic irritant dermatitis 'summation' type.) By repetition of the same stimulus, or by a combination of varying stimuli, the degree of impairment surpasses a critical level, in consequence of which a clinical disease (irritant contact dermatitis) ensues. This clinical disease, however, is only 'the tip of the iceberg'. Such stimuli may be chemical, mechanical and/or climatic. To find out which are the harmful factors requires a detailed case history about the patient's work, habits and hobbies, thus enabling him to avoid as many damaging exposures as is practical, and hence reducing the sum of causative factors. A number of causative factors are enumerated. The article is intended to be a catalyst to promote discussion on this subject.