To the Editor.—
We were concerned to read the article on topical application of colchicine for psoriasis by Kaidbey et al.1 In addition to side-effects in humans reported by Malkinson and Lynfield,2 among which were diarrhea, amenorrhea, and possibly hematological changes following systemic use of colchicine and irritant effects after local use of the substance, we want to report our observations on the effects of topical application of colchicine on guinea pig skin.Application of 0.1% or 1% colchicine in emulsifying ointment to about 10% of the total body surface area of the guinea pig for five days produces almost complete necrosis in the areas treated (Fig 1) and inhibition of mitosis in untreated regions of the animal skin. It also causes suppression of formation of the stratum granulosum (Fig 2, left). The effect of emulsifying ointment (Fig 2, right) on guinea pig skin is shown for comparison
Gaylarde PM, Sarkany I. Colchicine Therapy for Psoriasis. Arch Dermatol. 1976;112(4):556–557. doi:10.1001/archderm.1976.01630280074028
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