A Case of Ceftriaxone-Induced Acute Generalized Exanthematous Pustulosis/Generalized Pustular Psoriasis Overlap

Case Report

A 40-year-old man presented with pustular lesions all over the body for approximately 4 days’ duration. The onset of pustular lesions was accompanied by fever of a moderate degree and malaise. The patient admitted to unprotected extramarital contacts about a month and a half before the appearance of the pustular lesions. He stated that there was a small painless ulcer on the foreskin about 3 weeks before admission to our hospital, and the rapid plasma reagin card test was reported as reactive in a dilution of 1: 64 about 10 days before admission. He had been treated for primary syphilis with ceftriaxone for a duration of 10 days. However, the pustular lesions began appearing on the trunk on the sixth day after medical treatment and had spread to all body regions by the day of admission. Moreover, the patient mentioned that he had a history of psoriasis over a span of 20 years and had been treated with acitretin irregularly.

Physical examination revealed the presence of a generalized eruption of pustules on an erythematous base, which particularly involved the scalp, neck, trunk, and extremities (Fig. 1). The lesions were superficially loose pustules ranging from 2 to 20 mm in diameter and partial pustules dried up to form developed crusts on top of the ulcers. There were several asymptomatic erythematous lesions on both the palms and the soles of the feet. His mucous membranes, however, were not involved.

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Laboratory data disclosed the following values: white blood cell count of 13,670/mm³, hemoglobin level of 11.4 g/100 mL, neutrophil absolute value of 9,540/mm³, and lymphocyte absolute value of 1,950/mm³. Syphilis serologic studies revealed that the toluidine red unheated serum test (TRUST) was reported as reactive in a dilution of 1: 32. Multiple cultures of the blood and the cutaneous pustules were done but all were negative. The HIV status of the patient was negative. Cerebrospinal fluid examinations for lymphocytosis, the venereal diseases reference laboratory test, and TRUST showed negative results.

A biopsy specimen taken from one of the crusted lesions 6 days after admission showed parakeratosis and minimal hyperplasia in an area of the epidermis. The dermis showed an inflammatory infiltrate, comprising lymphocytes and plasma cells (Fig. 2a, b). A biopsy specimen taken from one of the plaque lesions 12 days after admission showed parakeratosis and intraepidermal neutrophilic granulocyte abscess. A biopsy of the dermis showed telangiectasia in the dermis papilla, dermal superficial perivascular lymphocytes, and neutrophil infiltration (Fig. 2c, d).

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Presumptive diagnoses of syphilis and AGEP/GPP overlap were both made. The patient was treated with acitretin (20 mg/day) after his admission. Three weeks after admission, the pustular lesions had completely healed (Fig. ​(Fig.3)3) and the TRUST titer had decreased to 1: 8.

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