Systematic review and meta-analysis of treatments and outcomes in primary localized cutaneous amyloidosis.

Background: Primary localized cutaneous amyloidosis (PLCA) is a skin-limited disorder characterized histologically by amyloid deposition in the papillary dermis.

Objectives: To review current treatment strategies and provide an updated perspective on the treatment of PLCA.

Methods: We searched the PubMed, EMBASE and Cochrane Library databases for eligible studies. Studies were divided into those that described nodular amyloidosis (NA) and those that described non-NA. Cohort studies were meta-analysed using a random effects model to evaluate the outcomes of different treatments, while case reports and case series were evaluated using the Mann-Whitney U-test.

Results: Overall, 116 studies involving 534 patients were included. Surgery was the most effective treatment option in patients with NA, with statistically significantly better outcomes compared with other treatments. For the non-NA group, 62 case-level studies (79 patients) and 20 cohort studies (418 patients) were analysed separately. Although there were no statistically significant differences between treatments in the case-level studies, biologic agents and Janus kinase (JAK) inhibitors may be promising treatments for refractory lesions. Among the cohort studies, partial response rates of 100.0%, 100.0%, 97.5%, 96.9% and 94.4% were achieved for transcutaneous electrical nerve stimulation, microneedling, laser therapies, topical therapies and systemic immunosuppressants, respectively; complete response rates of 22.2% and 2.5% were achieved for surgical interventions and laser therapies, respectively.

Conclusions: This study suggests that surgery is the most effective treatment option for NA, and laser therapy is recommended for patients with non-NA. Biologic agents and JAK inhibitors may be promising treatment options for lesions that do not respond to conventional therapies.