The cellular infiltrate in experimental allergic and toxic contact dermatitis. Effect of systemically administered corticosteroids.

The effect of systemically administered corticosteroids on allergic and toxic contact dermatitis in the guinea pig was studied. Dermatitis was provoked with dinitrochlorobenzene (DNCB). The influence of corticosteroids on the sensitization phase was also investigated. The epicutaneous test reactions were assessed with the naked eye, low-power microscopy, and a method based on the counting of infiltrating cells in the upper corium. Prednisolone injected in a dose of 5 mg/kg body weight daily for 4 days starting on the 1st day of sensitization or the 1st day of testing tended to shorten the duration of the contract allergic skin reaction as seen with the naked eye. Microscopically, a decrease in the number of infiltrating basophil granulocytes was found. Prednisolone had no convincing influence on the toxic contract eczematous reaction macroscopically or microscopically. Responses to weakly toxic doses of DNCB tended to fade earlier and to show small displacements of granulocytes in the differential count of infiltrating cells compared to controls. The results suggest that prednisolone given systemically influences only slightly the inflammatory cell infiltration in contact dermatitis in the guinea pig.