An enormous number of synthetic chemicals are incorporated in topical drugs, cosmetics and toiletries. These have the potential to cause irritant reactions when chronically applied to @entity1 skin. In predictive tests for assessing the irritancy potential of these chemicals, haired species, especially @entity95 , @entity840 and @entity19 , have figured prominently. Customarily these tests, including the renowned Draize @entity95 test, have entailed a single acute exposure or at most daily exposures over a few weeks. Estimation of @entity32 and tissue injury in these models have relied on visual assessment. We submit that this approach is no longer acceptable. Visual assessments are unreliable. Reactions which are scored equivalently by the naked eye may differ strikingly when examined histologically. Moreover, tissue injury may be present in clinically normal skin. Short-term results. even when abetted by routine histological evaluations, cannot predict the degree of injury from long-term exposures. Cosmetics and toiletries, for example, are used daily for decades, often over most of the lifespan of @entity1 who are well groomed. We present the hairless @entity19 as a convenient, reliable model for assessing the chronic @entity137 of diverse chemicals. Histological examination enables a detailed description of the different tissue components which participate in the complex cascade of changes that comprise the inflammatory response.

A hairless @entity19 model for assessing the chronic XXXX of topically applied chemicals.

@entity1 :: ('9606', 'Species') :: ['human', 'persons'] @entity32 :: ('MESH:D007249', 'Disease') :: ['inflammation'] @entity137 :: ('MESH:D064420', 'Disease') :: ['toxicity'] @entity19 :: ('10090', 'Species') :: ['mice', 'mouse'] @entity840 :: ('10141', 'Species') :: ['guinea pigs'] @entity95 :: ('9986', 'Species') :: ['rabbits', 'rabbit']
@entity137 :: (MESH:D064420,Disease) :: ['toxicity']
