An 8-year-old boy was brought to the emergency department with fever, bloody and mucous diarrhea, and abdominal pain. Specimens for stool culture were sent to the laboratory, and therapy with trimethoprim/sulfamethoxazole (TMP/SMX) was initiated. Hours after the first dose was given, the child complained of itching on the lateral aspect of the right thigh. Within the next 2 days, a well-defined, erythematous lesion with a central blister developed. The patient's mother remembered that 2 years earlier, a similar lesion had developed in the same area after the child was given TMP/SMX for a urinary tract infection.

This lesion is characteristic of a fixed drug eruption--an unusual reaction in which a lesion recurs in the same area when the patient is rechallenged by the offending drug. Sulfon- amides, antibiotics, anticonvulsants, analgesics, and anti-inflammatory drugs are most commonly associated with fixed drug eruptions.

The reaction usually develops within hours of taking the drug. After the first exposure, a solitary lesion may appear. After re-exposure to the same drug, new lesions may arise and the recurrent lesion may be larger than the original.

 The most commonly affected areas are the hands, feet, and genitalia; the limbs are more frequently affected than the trunk. Perioral and periorbital lesions may occur. Patients may have mild localized pruritus; systemic symptoms, such as fever, are absent or mild.

A fixed drug eruption may worsen for a few days after the responsible agent is discontinued and then resolve slowly over 1 or more weeks. As the lesion heals, crusting and scaling develop, leaving a persistent, dusky brown discoloration. The hyperpigmentation--which may be more pronounced in persons with brown skin--usually fades over time.

Within 10 days after TMP/SMX was discontinued, this child's lesion resolved, leaving a brownish pigmentation. The child's fever, abdominal pain, and diarrhea were attributed to bacterial gastroenteritis caused by TMP/SMX-resistant 

 He responded quickly to treatment with ciprofloxacin.

(Case and photographs courtesy of Elias Milgram, MD, of Miami.)

 Daoud MS, Schanbacher CF, Dicken CH. Recognizing cutaneous drug eruptions. Reaction patterns provide clues to causes. 

 Stern RS, Wintroub BU. Cutaneous reactions to drugs. In: Freedberg IM, Eisen AZ, Wolff K, et al, eds. 

Fitzpatrick's Dermatology in General Medicine.

 6th ed. New York: McGraw-Hill; 2003:1633-1642.


 2nd ed. Philadelphia: WB Saunders; 1993:67-68.

Skin Diseases

Consultant for Pediatricians Vol 5 No 8

An 8-year-old boy was brought to the emergency department with fever, bloody and mucous diarrhea, and abdominal pain. Specimens for stool culture were sent to the laboratory, and therapy with trimethoprim/sulfamethoxazole (TMP/SMX) was initiated.