To the Editor.—
We report a case in which erythema and postinflammatory pigmentation from anthralin burns of the normal skin surrounding a psoriatic plaque were noted to spare the Woronoff ring.
Report of a Case.—
A 46-year-old woman with psoriasis of four years' duration was placed on the modified Goeckerman regimen (consisting of 0.1% triamcinolone cream, anthralin, tar, and ultraviolet B). Some of the treated psoriatic plaques were noted to be surrounded by Woronoff rings. Accidentally, the patient applied anthralin to both the psoriatic plaques and the surrounding normal skin. Although the normal skin developed erythema from inflammation and subsequently postinflammatory pigmentation, the Woronoff ring remained unaffected (Figure).
A rim of blanched skin of approximately constant width surrounding treated psoriatic plaques has been called a Woronoff ring,1 which may be due to one or more inhibitors of prostaglandin synthesis diffusing outward from the plaque. The Woronoff ring does
Gupta AK, Ellis CN, Goldfarb MT, Voorhees JJ. Woronoff Ring During Anthralin Therapy for Psoriasis. Arch Dermatol. 1986;122(3):248. doi:10.1001/archderm.1986.01660150024007