Localized toxic follicular pustuloderma

A 40-year-old woman with a history of duodenal ulcers consulted for an acute outbreak of multiple pustular lesions without an underlying erythematous base affecting the face, neck, an, to a lesser extent, the upper third of the trunk (Fig. 1). She had been taking amoxicillin-clavulanic acid over the past 6 days for pharyngitis and fever. Given the persistence of fever and the possible allergic reaction to the drugs administered, even though we could have been dealing with a viral pharynx infection, we replaced the amoxicillin-clavulanic acid with another antibiotic with wide range (clarithromycin) empirically, and symptomatic treatment was started with antihistamines (loratadine). At the following visit, 1 week later, the patient had no fever, and the lesions were in the desquamative phase, thus indicating resolution of the condition. The histologic findings were compatible with toxic pustuloderma (subcorneal pustules, perivascular lymphohistiocytic infiltrate, etc.) (Fig. 2), although a perifollicular inflammatory infiltrate was also observed, composed mainly of neutrophils and eosinophils that penetrated and partially destroyed the external radicular sheath of the follicle (Fig. 3). Other histologic sections showed an intense neutrophilic infiltrate constituting a subepidermal pustule. Bacterial and fungal cultures of the lesions and pharyngeal smear proved negative. Laboratory tests revealed a globular sedimentation rate of 30 mm in the first hour, slight eosinophilia (5500 leukocytes, with 5.40% eosinophils), a discretely elevated ASLO titer (235 IU/mL), and slight thrombopenia (123,000 platelets). The remaining parameters were within the normal range.