Comorbidities Associated With Lichen Planopilaris: A Systematic Review and Meta-Analysis.

Area of Science:

• Dermatology
• Epidemiology
• Autoimmunology

Background:

• Lichen planopilaris (LPP) is a primary cicatricial alopecia.
• Associations between LPP and comorbid conditions like autoimmune, endocrine, and metabolic disorders are suggested but lack consistent data.
• Quantitative evaluation of these associations is needed.

Purpose of the Study:

• To quantitatively assess the prevalence and odds of comorbidities in patients diagnosed with lichen planopilaris.
• To provide a comprehensive overview of associated medical conditions based on existing literature.

Main Methods:

• A systematic review and meta-analysis was conducted using data from PubMed/MEDLINE, EMBASE, Cochrane Library, and Web of Science up to December 25, 2023.
• Included observational studies reporting comorbidities in LPP patients, adhering to PRISMA guidelines.
• Risk of bias was assessed using the Newcastle-Ottawa scale, and random-effect models were used for data analysis.

Main Results:

• The meta-analysis included 59 studies with 15,178 LPP patients and over 64 million controls.
• Significant associations were found for lichen planus, psoriasis, rosacea, melanoma, systemic lupus erythematosus, cutaneous squamous cell carcinoma, vitiligo, coronary artery disease, rheumatoid arthritis, hypothyroidism, thyroiditis, and iron deficiency anemia.
• Highest odds ratios were observed for lichen planus, psoriasis, rosacea, melanoma, and systemic lupus erythematosus.

Conclusions:

• Lichen planopilaris demonstrates significant associations with autoimmune disorders, thyroid diseases, and various skin cancers.
• Further research is warranted to understand the underlying pathogenesis of these comorbidities.
• Establishing appropriate screening criteria for associated conditions in LPP patients is recommended.