Wolf's isotopic response: rosacea appearing at the site of healed herpes zoster

A 40-year-old man developed an erythematous rash on the right side of his face 3 weeks after a herpes zoster infection at the same location. Examination revealed an erythematous papular eruption and telangiectasias along the ophthalmic and maxillary divisions of the right trigeminal nerve, exactly at the site of the consistent with previous herpes zoster infection, Wolf's isotopic response. Histological examination showed vascular ectatic dilatation and perivascular and perifollicular infiltration of lymphocytes and histiocytes consistent with rosacea. The rash was resistant to oral doxycycline and topical metronidazole 1% cream and resolved with oral isotretinoin therapy.