Cutaneous Hair Loss Disorders: Diagnosis and Treatment of DLE, Folliculitis Decalvans, Dissecting Cellulitis, and AKN

Conclusions

• Discoid lupus erythematosus is often diagnosable clinically and dermoscopically, and early recognition matters because it can progress to systemic lupus erythematosus.
• Starting hydroxychloroquine early in DLE appears to substantially reduce the risk of progression to SLE, making it a key foundational therapy.
• Smoking cessation and photoprotection are important adjuncts in DLE because they improve disease control and smoking may reduce hydroxychloroquine effectiveness.
• For DLE, high-potency topical steroids and intralesional steroids are preferred first-line local treatments, with calcineurin inhibitors and topical retinoids as useful alternatives.
• Folliculitis decalvans is a chronic relapsing inflammatory scarring alopecia with prominent pustules, crusting, tufting, and male predominance.
• Dermoscopy helps distinguish FD activity and severity by showing yellow signs and red signs, and can also be used to monitor response to treatment.
• Folliculitis decalvans may occur in women and in patients receiving EGFR inhibitors, suggesting that the condition has broader associations than traditionally appreciated.
• Treatment of FD is stepwise and often requires antibiotics, isotretinoin, steroids, or immunomodulators, but no single therapy is consistently curative.
• Dissecting cellulitis is a deeper and more destructive follicular occlusion disorder than FD, characterized by abscesses, sinus tracts, and major scalp disfigurement.
• Dissecting cellulitis overlaps clinically and biologically with hidradenitis suppurativa, acne conglobata, pilonidal disease, and sometimes spondyloarthropathy.
• Because dissecting cellulitis is often more inflammatory and refractory, management generally escalates beyond topicals to oral agents, biologics, procedures, and surgery.
• Emerging biologic and targeted therapies such as TNF-alpha inhibitors, IL-17/23 agents, JAK inhibitors, and apremilast may help refractory dissecting cellulitis, but evidence remains limited and mixed.
• Both FD and dissecting cellulitis can carry a risk of squamous cell carcinoma, so long-standing severe disease warrants vigilance.
• Acne keloidalis nuchae is a chronic follicular inflammatory condition with strong male and Black-patient predominance and is likely driven by a mix of inflammation, trauma, ingrown hairs, and androgens.
• AKN treatment should be matched to lesion morphology and extent, ranging from topical/intralesional therapy and retinoids to excision, laser-based procedures, and adjuvant strategies for recurrence prevention.
• Overall, these scarring alopecias are managed with severity-based treatment ladders, but their complexity and frequent refractoriness show that better therapies and a stronger mechanistic understanding are still needed.