Pustular eruption in a malaria patient treated with chloroquine

A 42‐year‐old Thai woman with Plasmodium vivax malaria was treated with a total dose of 1800 mg of chloroquine phosphate over 6 h. Acetaminophen was administered to reduce fever. The patient awoke the next morning with diffuse macular erythema, studded with 1–2 mm vesicles and pustules, predominantly on the face and the extremities ( Fig. 1). Some pustules were follicular. The mucous membranes, palms, and soles were unaffected. A gram stain of the pustule contents showed only scattered neutrophils. A skin biopsy from a lesion on the upper leg showed the features of a drug‐induced pustular eruption: cell‐poor subepidermal blisters with scattered subcorneal pustules ( Fig. 2), mild spongiosis, and a sparse infiltrate of neutrophils and eosinophils in the papillary dermis. 1 A urine screen (Lignin test) for sulfonamides was negative, and high pressure liquid chromatography analysis of the serum showed no sulfadoxine. Hematolgy and biochemistry values, erythrocyte sedimentation rate, and glucose 6‐phosphate dehydrogenase levels were normal. Serologies for mycoplasma antibody, Herpes simplex immunoglobulin M (IgM) and IgG, cytomegalovirus IgM, anti‐human immunodeficiency virus, venereal disease research laboratory test, antinuclear antibody, alpha‐fetoprotein, and carcino‐embryonic antigen were negative. A hepatitis B panel, serum pregnancy test, and three sets of blood cultures were negative. A chest X‐ray was normal. The patient was in otherwise good health and had no history of skin diseases. Chloroquine was discontinued and the eruption quickly resolved with mild desquamation. 1Erythematous macules studded with small pustules (arrows) on the upper legs2Biopsy specimen from a lesion on the leg contains cell‐poor subepidermal blisters and subcorneal pustules (arrows) (hematoxylin and eosin, original magnification, ×400)