What is the pathophysiology, clinical features, diagnosis, and management of acne keloidalis in a young to middle-aged male of African descent?

Acne Keloidalis Nuchae: Comprehensive Clinical Overview

Pathophysiology

Acne keloidalis nuchae (AKN) is a primary cicatricial (scarring) alopecia, not a true keloid or variant of acne vulgaris, despite its misleading name. 1

The pathogenesis involves:

• Premature destruction of the inner root sheath at the isthmus level, leading to follicular inflammation and eventual scarring 1
• Chronic lymphocytic and plasmacytic inflammation concentrated at the isthmus and lower infundibulum 1
• Lamellar fibroplasia (concentric scarring) surrounding affected follicles 1
• Complete loss of sebaceous glands associated with destroyed follicles 1
• Thinning and eventual destruction of follicular epithelium, leaving "naked" hair fragments 1

Contributing factors include androgens, mechanical trauma (particularly from close shaving and tight collars), ingrown hairs, chronic inflammation, and genetic predisposition, though the exact trigger remains unknown 2, 3. Importantly, microorganisms do not appear to play a primary pathogenic role, distinguishing AKN from infectious folliculitis 1.

Clinical Features

AKN presents as firm follicular papules and pustules on the occipital and nuchal scalp that coalesce into hypertrophic plaques and nodules, occurring almost exclusively in post-pubertal males of African descent. 2, 4

Demographics and Epidemiology

• Prevalence ranges from 0.7% to 16.1% in affected populations 2, 5
• Occurs predominantly in males of African descent; rare in females 2, 3
• Onset typically post-pubertal, rare after age 55 years 2
• Mean age at presentation: 29 years 5

Clinical Presentation

• Initial stage: Small (1-4 mm) firm follicular papules and pustules on the lower occipital/nuchal region 4, 1
• Progressive stage: Papules coalesce into firm hypertrophic plaques and nodules, sometimes forming tumorous masses 2, 4
• Symptoms: Itching (71.1% of cases), pain (9.6%), bleeding during haircuts (1.2%) 3
• Scarring alopecia: Permanent hair loss in affected areas, though patients report greater distress from visible keloidal lesions than from alopecia 2
• Subclinical disease: Histologically abnormal follicles and true follicular scars may be present in normal-appearing scalp skin 1

Diagnosis

Diagnosis is primarily clinical, based on characteristic firm follicular papules and plaques on the occipital/nuchal scalp in a young adult male of African descent. 2, 4

Clinical Diagnosis

• Identify firm follicular papules, pustules, or coalesced plaques on the nape of the neck 4
• Document lesion size, distribution, and presence of scarring alopecia 5
• Note symptoms: pruritus, pain, bleeding with haircuts 3

Histopathology (when needed for confirmation)

• Transverse sectioning of 4-mm punch biopsies from lesional, perilesional, and normal-appearing scalp 1
• Key findings: chronic perifollicular inflammation at the isthmus level, lamellar fibroplasia, loss of sebaceous glands, follicular destruction with naked hair shafts 1
• Absence of significant microorganisms distinguishes AKN from infectious folliculitis 1

Microbiologic Testing

• Not routinely recommended, as microorganisms are not primary pathogens 1
• Consider only if secondary infection is suspected clinically 2

Differential Diagnosis

Key differentials to exclude:

• Keloid: True keloids occur at sites of trauma and have a tendency to develop in other body areas; patients with AKN do not typically form keloids elsewhere 2
• Pseudofolliculitis barbae: Occurs on the beard area (not occipital scalp), caused by ingrown hairs from shaving; no etiologic relationship to AKN 1
• Dissecting cellulitis of the scalp: Affects vertex and crown, presents with interconnecting sinus tracts and purulent discharge 1
• Folliculitis decalvans: Affects vertex, presents with tufted folliculitis and crusting 1
• Bacterial folliculitis: Acute onset, responds to antibiotics, lacks chronic scarring pattern 2

Management

Treatment depends on disease stage: early inflammatory lesions respond to medical therapy, while established keloidal plaques require surgical excision. 6, 4

Medical Management for Early/Inflammatory Lesions

First-Line Therapy

• Intralesional triamcinolone acetonide 10 mg/mL into inflammatory follicular lesions 6
• Intralesional triamcinolone acetonide 40 mg/mL into hypertrophic scars and keloids 6
• Flattens lesions within 48-72 hours 6
• Efficacious for occasional or stubborn lesions, but not effective for multiple widespread lesions 6

Topical Therapy

• Topical corticosteroids (high-potency) for inflammatory papules 2, 4
• Topical antibiotics (clindamycin, erythromycin) for pustular lesions 2, 4
• Note: These have disappointing results as monotherapy 4

Systemic Therapy

• Oral antibiotics (tetracyclines) for widespread inflammatory disease 2, 4
• Limited efficacy; often disappointing results 4

Contraindications for Intralesional Corticosteroids

• Active infections (impetigo, herpes) at injection site 6
• Previous hypersensitivity to triamcinolone 6
• Active tuberculosis or systemic fungal infection (for large injections) 6
• Uncontrolled diabetes, heart failure, or severe hypertension 6

Adverse Effects of Intralesional Corticosteroids

• Local atrophy, pigmentary changes, telangiectasias, hypertrichosis 6
• Impaired wound healing, infections 6
• Contact allergic dermatitis from benzyl alcohol preservative 6
• Hypothalamic-pituitary-adrenal axis suppression with repeated injections 6

Surgical Management for Established Keloidal Lesions

Surgical excision with secondary intention healing is the definitive treatment for established keloidal plaques and nodules, offering good cosmesis with minimal recurrence. 4

• Excision with secondary intention healing: Preferred for established lesions; results in good cosmesis with little to no recurrence 4
• Excision with primary closure or skin grafting: Alternative surgical approaches 4
• Hair-removal lasers: May be beneficial 4

Treatment Pitfalls to Avoid

Critical errors in management:

• Never use caustic substances (acids, engine oil, traditional corrosives): These create larger lesions and unsightly scars 2, 3
• Avoid Neo-medrol (topical steroid-antibiotic combination) as primary treatment; limited efficacy 3
• Do not delay treatment once lesions become keloidal; medical therapy is ineffective at this stage 4, 5
• Intralesional steroids are not effective for multiple widespread lesions 6

Patient Counseling

Disease Education

• Explain that AKN is a chronic scarring condition, not a true keloid, and does not indicate a tendency to form keloids elsewhere on the body 2
• Emphasize that the condition is a form of primary scarring alopecia with permanent hair loss in affected areas 1
• Discuss the chronic, recurrent nature of the disease; delay in seeking treatment has negligible effect on progression once inflammatory stage has passed 5

Prevention and Lifestyle Modifications

• Avoid close shaving and tight collars that cause mechanical trauma to the occipital scalp 2, 3
• Use personal shaving kits; do not share instruments at barbershops due to risk of blood-borne infection transmission from bleeding lesions 2, 3
• Seek treatment early when small papules first appear to prevent progression to large keloidal masses 2, 5

Treatment Expectations

• Early inflammatory lesions respond to intralesional corticosteroids within 48-72 hours 6
• Established keloidal plaques require surgical excision; medical therapy is ineffective 4
• Mean follow-up duration is approximately 22 weeks; lesions may spread (26.5% of cases) or resolve (14.7% of cases) during this period 5
• Recurrence is possible even after treatment; ongoing monitoring is necessary 4, 5

Psychosocial Impact

• Acknowledge that visible keloidal lesions cause significant distress, often more than the resulting alopecia 2
• Address quality of life concerns; the condition has substantial impact on self-image and social functioning 2, 5
• Encourage early treatment to prevent unsightly lesions that affect quality of life 2

Safety Counseling

• Warn against self-medication with caustic substances, engine oil, or traditional remedies, which worsen scarring 2, 3
• Educate about safe shaving practices to prevent bleeding and potential disease transmission 2, 3
• Discuss realistic expectations: no universally effective treatment exists, and the condition remains chronic and recurrent 5