What are the introduction, clinical features, and management of folliculitis decalvans?

Folliculitis Decalvans: Clinical Overview and Management

Definition and Introduction

Folliculitis decalvans is a rare primary neutrophilic cicatricial (scarring) alopecia characterized by chronic suppurative folliculitis that results in permanent, progressive hair loss, predominantly affecting the vertex and occipital scalp of young to middle-aged adults. 1

• This inflammatory scalp disorder occurs most commonly in patients aged 25-45 years, with a slight male predominance 2
• The pathogenesis remains incompletely understood but involves Staphylococcus aureus colonization combined with a deficient host immune response 1
• Familial cases have been documented, suggesting possible genetic susceptibility 2
• The disease follows a chronic, relapsing course that causes significant psychological distress due to its disfiguring nature 3, 1

Clinical Features

Primary Lesion Characteristics

• Follicular pustules with purulent discharge are the hallmark finding, accompanied by diffuse and perifollicular erythema that heals with centrifugal scarring 3, 1
• Follicular tufting (polytrichia) develops where multiple hair shafts emerge from a single dilated follicular opening 1
• Hemorrhagic crusts and erosions frequently cover the affected areas 3, 1
• Loss of follicular ostia (openings) occurs as scarring progresses 1

Distribution and Symptoms

• Lesions predominantly affect the vertex and occipital scalp regions 3, 1
• Patients report pain, pruritus (itching), or burning sensations (trichodynia) 3, 4
• Involvement of body sites other than the scalp is rare 3

Severity Assessment

• Severity is classified by the maximum diameter of the largest alopecic patch: slight (<2 cm), moderate (2-4.99 cm), or severe (≥5 cm) 2
• Disease onset before age 25 years and the presence of pustules are independent predictors of severe folliculitis decalvans 2
• Severe disease occurs in approximately 21% of patients 2

Diagnostic Approach

Clinical Diagnosis

• Diagnosis is established based on the characteristic clinical presentation of pustular folliculitis with progressive scarring alopecia 3
• Histopathology shows predominantly neutrophilic inflammatory infiltrate in early lesions, with lymphocytes and plasma cells appearing in advanced lesions 1

Microbiological Investigation

• Direct microscopic examination and mycological culture should be performed to exclude fungal infection 3
• Staphylococcus aureus can frequently be isolated from pustules, supporting its pathogenic role 3, 1

Management Strategy

First-Line Antimicrobial Therapy

Oral antibiotics targeting S. aureus with anti-inflammatory properties constitute first-line therapy, with tetracyclines and the combination of clindamycin plus rifampicin showing the highest efficacy. 2

Tetracyclines

• Tetracyclines improve 90% of patients with a mean response duration of 4.6 months 2
• Standard dosing regimens are used until clinical improvement occurs 2

Clindamycin-Rifampicin Combination

• The combination of clindamycin with rifampicin achieves 100% improvement rates with a mean response duration of 7.2 months, making it the most effective antibiotic regimen 2
• This combination provides both antimicrobial coverage and anti-inflammatory effects 1

Fusidic Acid

• Oral fusidic acid 500 mg three times daily represents an effective alternative with few adverse effects 3
• Treatment duration of 2-3 months has shown good clinical results with reduced erythema, suppuration, and partial hair regrowth 3
• Fusidic acid maintains low resistance rates despite years of clinical use 3
• This anti-staphylococcal agent has high oral bioavailability and a long plasma half-life 3

Adjunctive Topical Therapy

• Topical betamethasone dipropionate 0.05% with salicylic acid 3% lotion applied once daily reduces inflammation 3
• Azelaic acid 5% lotion can be added for additional anti-inflammatory benefit 3
• Topical fusidic acid is widely used as adjuvant treatment 3

Maintenance and Prevention of Relapse

• Maintenance therapy with zinc sulfate after initial antibiotic response may prevent recurrence 3
• The disease typically progresses when treatment is discontinued, necessitating long-term management strategies 1

Refractory Disease

• For cases refractory to antibiotic and anti-inflammatory therapies, intensity-modulated radiation therapy (IMRT) can eliminate hair follicles and provide lasting symptom relief 4
• Radiation dosing of 11 Gy delivered in fractionated courses (5 Gy in 5 fractions, followed by 6 Gy if needed) achieves near-complete epilation and abolishes pain and pruritus 4
• This radical approach should be reserved for chronic suppurative disease with persistent trichodynia unresponsive to conventional therapy 4

Critical Management Pitfalls

• Do not discontinue antibiotic therapy prematurely, as the disease typically relapses when treatment stops; plan for extended courses or maintenance strategies 1, 2
• Treatment must focus on both eradicating S. aureus and providing anti-inflammatory effects 1
• Regular follow-up is essential to monitor for recurrence and adjust therapy accordingly 3
• Early aggressive treatment is particularly important in patients with onset before age 25 or prominent pustulation, as these factors predict severe disease 2