Amyloidosis is a medical term that can refer to a number of conditions. These conditions all result from an abnormal collection of amyloid proteins in one place. In the case of lichen amyloidosis, the deposits collect in the skin and form itchy, raised bumps. Lichen amyloidosis is associated with certain diseases.
When amyloid proteins collect in someone with lichen amyloidosis, they generally form on the front of the legs and feet but may also be found on the back, thighs, and arms. The initial symptom is a rash that is extremely itchy. The rash is made up of lots of flat red or brown bumps that are raised and flaky. These lesions can join together to form larger plaques on the skin.
The most common time of life to develop lichen amyloidosis is between 50 and 60 years of age. People with Chinese ancestors are most likely to have the condition, although it is also more common in Southeast Asia and South America than in other areas of the world. Men suffer from it more often than women. The condition may affect patients who suffer from atopic dermatitis or other skin conditions like lichen planus or mycosis fungoides.
An inherited syndrome called Sipple syndrome is also associated with lichen amyloidosis. People with this syndrome may suffer from thyroid problems and adrenal and thyroid cancers. Usually, these people only have rashes on the back between the shoulder blades.
Doctors diagnose the condition through visual examination of the lesions and also from a microscopic examination of the affected tissue. Treatment of lichen amyloidosis patients usually aims to control the itching. Antihistamines can help, as can skin creams with steroids and steroid injections into the lesions. Phototherapy with ultraviolet light may have a beneficial effect, as can application of dimethyl sulfoxide.
Removal of the plaques through surgery is another possible treatment. Laser surgery, dermabrasion, and simple excision of the lesions can help resolve the issue temporarily. Generally, the rash returns, so surgery is not a permanent cure.
Lichen amyloidosis is part of a group of skin conditions known as primary localized cutaneous amyloidosis. These conditions only affect parts of the skin and do not spread to other parts of the body. The lichen form is the most common of the localized skin amyloidoses and is distinguishable from other types by the appearance, itchiness, and location of the rash. More serious forms of amyloidosis include systemic amyloidosis, where amyloid deposits settle around organs and can cause death within a few years.