Original article
Pityrosporum folliculitis: A retrospective review of 110 cases

https://doi.org/10.1016/j.jaad.2017.11.022Get rights and content

Background

Pityrosporum folliculitis is an under-recognized eruption of the face and upper portion of the trunk that may be confused with, or occur simultaneously with, acne vulgaris.

Objective

We sought to characterize risk factors for Pityrosporum folliculitis, its clinical presentation, and its response to treatment.

Methods

A retrospective chart review was performed on all patients age 0 to 21 years seen at our facility from 2010 to 2015 with Pityrosporum folliculitis confirmed by a potassium hydroxide preparation.

Results

Of 110 qualifying patients, more than 75% had acne that had recently been treated with antibiotics, and when recorded, 65% reported pruritus. Clinical examination demonstrated numerous 1- to 2-mm monomorphic papules and pustules that were typically on the forehead extending into the hairline and on the upper portion of the back. The most common treatment was ketoconazole shampoo, which led to improvement or resolution in most cases. Some patients required oral azole antifungals.

Limitations

This study was retrospective and relied on providers describing and interpreting the clinical findings and potassium hydroxide preparations. No standard grading system was used.

Conclusion

Unlike classic acne vulgaris, Pityrosporum folliculitis was more common after antibiotic use. It presented as fine monomorphic, pruritic papules and pustules along the hairline and on the upper portion of the back, and it improved with topical or oral azole antifungal therapy.

Section snippets

Methods

A retrospective chart review was performed of all patients age 0 to 21 years with Pityrosporum folliculitis who were seen by members of the University of Massachusetts Division of Dermatology from 2010 to 2015. Institutional review board approval was obtained before this study. Medical Informatics performed a search of qualifying patients using International Classification of Diseases, Ninth Revision codes 706.1 (acne), 704.8 (folliculitis), and/or 111.0 (infection by Pityrosporum), and

Results

In total, 110 patients with documented Pityrosporum folliculitis were identified. The average age at diagnosis was 15 years. The majority were white and female. Presence or absence of pruritus was recorded in 44% of the included charts; pruritus was present in 65% of these 48 patients. Less than 20% of patients had associated seborrheic dermatitis and/or tinea versicolor. Four patients reported antecedent topical steroid use. More than 75% described persistent acne recently treated with an

Discussion

Acne affects approximately 85% of adolescents. Patients with acne often have increased sebum production and follicular hyperkeratinization leading to occlusion.6 Given that these factors and antibiotic therapy for acne predispose to development of Pityrosporum folliculitis, the 2 conditions may occur together. It is important to identify coexisting Pityrosporum folliculitis and treat it appropriately, as continued acne treatment will not improve and may worsen this condition.

Pityrosporum

References (8)

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Funding sources: None.

Conflicts of interest: None disclosed.

A brief version of this information in this article was presented as a poster at the World Congress of Pediatric Dermatology, Chicago, IL; July 6-9, 2017.

Reprints not available from the authors.

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