Cutaneously applied erythromycin base reduces various types of inflammatory reactions in mouse ear.

Erythromycin base was tested by brushing a solution onto the skin in various models of non-immune and immune inflammation produced in mouse ear, namely inflammations induced by croton oil and cantharidin, primary irritation by picryl chloride, and contact hypersensitivity reactions to oxazolone and picryl chloride. On the non-immune inflammations, erythromycin displayed a greater effect than indomethacin, phenylbutazone or acetylsalicylic acid, though less than that of hydrocortisone acetate. It inhibited the hypersensitivity reactions less well. These results suggest some participation of an anti-inflammatory mechanism in the clinical effectiveness of cutaneously applied erythromycin base in some forms of acne.