Eosinophilic folliculitis (EF) is a chronic, culture-negative folliculitis of unknown etiology. The term "eosinophilic pustular folliculitis" is used interchangeably.

EF is characterized histologically by eosinophilic follicular inflammation. There are several variants:

• Immunosuppression-associated EF (discussed herein)
• Ofuji disease
• Eosinophilic pustular dermatosis of infancy

Immunosuppression-associated EF is more common in males than females. It is usually seen in patients with HIV infection, but it has also been reported to occur in other immunocompromised patients, particularly those with bone marrow or heart transplants, lymphoma, leukemia, or myelodysplastic syndrome. In HIV, EF usually occurs in patients with a CD4 count of less than 300 cells/mm³. EF has also been reported in sanitation workers in Hong Kong from protective gear during the COVID-19 pandemic. 

Clinically, the disorder is characterized by recurrent, usually intensely pruritic papules and pustules in areas often affected by acne vulgaris. Occasionally, a more widespread distribution is seen. EF can be extremely symptomatic and refractory to treatment, but it may spontaneously improve as CD4 counts rise secondary to antiretroviral therapy for HIV. It can also worsen or manifest as part of an immune reconstitution phase.