Background: Metronidazole is utilized as a topical treatment for rosacea. Various other topical drugs have been evaluated for effective treatment of rosacea, which include: erythromycin, clarithromycin,
azithromycin, and 13-cis-retinoic acid. The activity of metronidazole includes blocking neutrophil
involvement in the development of rosacea. Antihistamine drugs can be administered orally or as
topical agents and are utilized in the treatment of allergic conjunctivitis and urticaria. This work
demonstrates the effectiveness of treating facial erythema and papules utilizing diphenhydramine
hydrochloride and zinc acetate in combination with metronidazole therapy.
Case report: An individual treating rosacea with metronidazole and a common moisturizer showed significant erythema and papules present on the forehead, cheeks, and nose. The subject was allowed to
continue the routine therapy utilizing metronidazole and moisturizer, but began the simultaneous
application of a 2% diphenhydramine hydrochloride and 0.1% zinc acetate cream (applied 3 times daily) for 44 hours. The subject followed routine work and eating schedules. After 44 hours of treatment the subject was again evaluated utilizing the physicians visual analog scale(PVAS) for effectiveness of therapy.There was substantial reduction of facial located erythema and the size of papules due to the application of diphenhydramine hydrochloride and zinc
acetate cream.
Conclusions: The application of a 2% diphenhydramine hydrochloride and 0.1% zinc acetate cream combined
with metronidazole and a moisturizer induced substantial reduction of erythema and papule size.
The cream is simple to apply on a daily basis and does not interfere with the beneficial effects
of metronidazole and moisturizer. The cream is not irritating and can be applied to the same areas as the metronidazole.

Keywords: Rosacea, papules, Erythema, antihistamines, PVAS