MERCURY EXANTHEM

We have observed 9 male patients with a generalized rash following the topical use of an over-the-counter antiparasitic powder (MOM(R)), con taining ammoniated (11.2 g%) and metallic (4.2 g%) mercury, to treat p hthiriasis (lice infestation). Primary and intensely erythemato-exudat ive lesions of the pubic region and genitals were associated with inve rted erythema of the upper inner thighs and, in severe cases, involvem ent of the face, neck, trunk and major flexures. Eruptions included ex anthematic, papulo-vesicular, purpuric and erythema-multiforme-like cl inical pictures. 7 of the 9 cases presented with general malaise and p yrexia. A positive patch test reaction to ammoniated mercury was obser ved in all cases. There are probably 3 routes of powder exposure behin d this type of rash: (i) direct skin contact (ii) airborne skin contac t; (iii) inhalation.