Facial and extrafacial eosinophilic pustular folliculitis: a clinical and histopathological comparative study

Abstract

Although more than 300 cases of eosinophilic pustular folliculitis (EPF) have been reported to date, differences in clinicohistopathological findings among affected sites have not yet been evaluated. To evaluate differences in the clinical and histopathological features of facial and extrafacial EPF. Forty-six patients diagnosed with EPF were classified into those with facial and extrafacial disease according to the affected site. Clinical and histopathological characteristics were retrospectively compared, using all data available in the patient medical records. There were no significant between-group differences in subject ages at presentation, but a male predominance was observed in the extrafacial group. In addition, immunosuppression-associated type EPF was more common in the extrafacial group. Eruptions of plaques with an annular appearance were more common in the facial group. Histologically, perifollicular infiltration of eosinophils occurred more frequently in the facial group, whereas perivascular patterns occurred more frequently in the extrafacial group. Follicular mucinosis and exocytosis of inflammatory cells in the hair follicles were strongly associated with facial EPF. The clinical and histopathological characteristics of patients with facial and extrafacial EPF differ, suggesting the involvement of different pathogenic processes in the development of EPF at different sites.