Association of primary cutaneous amyloidosis with atopic dermatitis: a nationwide population-based study in Taiwan

Primary cutaneous amyloidosis (PCA) is a pruritic skin disorder most commonly seen in Southeast Asia and South America. Association of PCA with atopic dermatitis (AD) has been reported in the literature. However, no large-scale epidemiological study of PCA and its associations with other diseases has been conducted so far.

We aimed to provide overall demographic data and comorbidities of patients with PCA based on a nationwide database in Taiwan.

Cases of PCA were collected from records of National Health Insurance claims from 2000 to 2007. We analysed patients' gender, age when the diagnosis was first made, and the overall 8-year prevalence. We also investigated comorbidities.

The overall 8-year prevalence of PCA was 7·87 per 10,000 persons. Although there was no significant gender difference in the prevalence of PCA, men and women showed a different peak age (men, 71-80 years; women, 41-50 years) and a different age distribution at diagnosis. The mean age at diagnosis of PCA was significantly younger for women than for men. Men sought medical assistance for PCA more frequently than women. There was a higher disease activity from May to September than during other months. PCA was strongly associated with AD (odds ratio 7·18). Patients with PCA had a higher comorbidity of hyperlipidaemia and diabetes mellitus.

This is the first nationwide population-based epidemiological study of PCA. We demonstrate that PCA can be associated with other disorders, especially AD.