Primary localized cutaneous amyloidosis (PLCA) is a condition in which clumps of abnormal proteins called amyloids build up in the skin, specifically in the wave-like projections (dermal papillae) between the top two layers of skin (the dermis and the epidermis). The primary feature of PLCA is patches of skin with abnormal texture or color. The appearance of these patches defines three forms of the condition: lichen amyloidosis, macular amyloidosis, and nodular amyloidosis.
PLCA can be caused by mutations in the OSMR or IL31RA gene. When caused by an OSMR gene mutation, the condition is classified as type 1, while an IL31RA gene mutation causes type 2. Mutations in either gene are likely involved in lichen and macular amyloidosis, which are thought to be related conditions that arise through similar disease mechanisms. The genetic basis of nodular amyloidosis is unknown.
PLCA occurs worldwide, most commonly in Southeast Asia and South America. The prevalence of the condition is unknown.
In most cases, PLCA is not inherited and occurs in people with no history of the condition in their family.
Published Date: March 01, 2017Published By: National Institutes of Health