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Eosinophilic pustular folliculitis
Eosinophilic pustular folliculitis
Clinical features Eosinophilic pustular folliculitis (Ofuji disease) is a rare dermatosis seen primarily in Japanese and Chinese patients, although occasional reports from Europe and the USA are encountered.1โ5 It is a disease which particularly affects the seborrheic regions and, therefore, lesions are predominantly present on the face and back.6,7 The extensor surfaces of the upper limbs are also frequently affected. Acral involvement is uncommon.7โ10 Patients present with crops of occasionally pruritic, sterile follicular papulopustules measuring 1โ2โฏmm in diameter, grouped to form small plaques, which characteristically spread centrifugally to produce an annular or serpiginous lesion.1,6 The disease is typically recurrent, and spontaneous resolution within months to several years is characteristic.11,12 Healing is often associated with residual postinflammatory hyperpigmentation.1 The peak incidence is in the third and fourth decades, although children and infants can be affected.7,14โ17 Males have been thought to be predominantly affected (5โ:โ1), but recent studies have shown an equal sex incidence.7,13,18 Sometimes there is a past or present history of acne vulgaris.
Differential diagnosis As mentioned above, there is considerable overlap between eosinophilic folliculitis associated with HIV infection and Ofuji disease. The latter condition tends to form arcuate plaques. Histologically, well-developed large eosinophilic pustules in the pilar canals are characteristic of Ofuji disease but are less common in HIV-associated eosinophilic folliculitis.63
Identical histology may be seen in epidermal fungal infections, and special stains are essential to exclude this possibility.55,57,64โ67
It can also be difficult to differentiate eosinophilic folliculitis from mycosis fungoides. Initial lesions of mycosis fungoides can sometimes resemble eosinophilic folliculitis. Similarly, anaplastic large cell lymphoma can have lesions mimicking eosinophilic folliculitis.57 The presence of atypical lymphocytes, clonality studies, and multiple biopsies over time may help clarify the differential diagnosis.
Extensive laboratory investigations reveal leukocytosis with hypereosinophilia.18 Serum IgE levels may be increased.5,19,20
Similar cases have been reported in Caucasians in association with HIV infection.3,4,21โ28 However, based on the clinical and histologic findings, many authors regard HIV-associated eosinophilic folliculitis as a separate entity.25,27 Pruritus, which is always present in patients with HIV-associated eosinophilic folliculitis, is seen only in occasional patients with Ofuji disease.29
A small number of childhood cases of eosinophilic pustular folliculitis, including several in neonates, have also been reported.16,17,30โ36 Some authors prefer to categorize these as a separate entity, whereas others feel that this