Comparison of croton oil and cantharidin induced inflammations of the mouse ear and their modification by topically applied drugs.

The inflammatory response to topical application of cantharidin or croton oil to the mouse ear was studied. Croton oil dermatitis developed more rapidly and reached its apparent peak earlier than cantharidin dermatitis. Either dermatitis detected topical rather than systemic antiinflammatory activity of glucocorticosteroids and distinguished between steroid esters and their alcohols. A number of drugs were tested for their ability, after topical application, to inhibit these dermatitides. Nonsteroidal antiinflammatory drugs weakly inhibited croton oil dermatitis but were without effect on cantharidin dermatitis. Beta-adrenergic agonists and antagonists inhibited both dermatitides. It is suggested that the use of these simple models of dermatitis is appropriate for identifying new, topically effective antiinflammatory drugs.