Biopsy is needed for the diagnosis
Two scalp biopsies should be performed to make the diagnosis. Recommended guidelines for sampling the scalp include performance of 4-mm punch biopsies extending into the fat at 2 diff erent clinically active sites.7 One biopsy should be processed for standard horizontal sectioning, but the second biopsy should be bisected vertically, with half sent for histologic examination and the other half for tissue culture (fungal and bacterial). An additional subsequent biopsy for direct immunofluorescence may also be considered if the initial biopsies are nondiagnostic.
Bacterial and fungal cultures collected from an intact pustule on the scalp with a standard culture swab should also be undertaken with pustular disease. If scale is present, a potassium hydroxide examination can help establish the diagnosis of a fungal etiology.
Doxycycline, intralesional corticosteroids are the first line of Tx
Management of FD can be difficult, and long-term treatment is often necessary. You’ll need to explain to patients that their current hair loss is permanent and that the goal of treatment is to decrease inflammation and prevent further balding.
After initial bacterial cultures and sensitivities are obtained, primary treatment is aimed at eliminating S aureus colonization. Often, this requires oral antibiotic therapy, most commonly doxycycline 100 mg twice daily5(strength of recommendation [SOR]: C). Topical antibiotics, however, may be used in mild cases; options include 2% mupirocin, 1% clindamycin, 1.5% fusidic acid, or 2% erythromycin applied twice daily1(SOR: C). In recalcitrant cases, a common treatment regimen includes oral rifampin 300 mg and clindamycin 300 mg twice daily for 10 weeks4(SOR: C).
Adjunctive topical and intralesional corticosteroids may help reduce inflammation and provide symptomatic relief from itching, burning, and pain. Topical class I or II corticosteroids can be used twice daily, whereas intralesional triamcinolone acetonide (combined with topical and/or oral antibiotics) may be administered every 4 to 6 weeks, starting at a concentration of 10 mg/mL1(SOR: C). Oral corticosteroids should only be considered for highly active and rapidly progressive symptoms.
Dapsone may also be considered as a treatment option for FD due to its antimicrobial activity and anti-inflammatory action directed toward neutrophil metabolism. Relapse, however, is frequent after treatment withdrawal1(SOR: C).