What is alopecia mucinosa?
Alopecia mucinosa is also known as follicular mucinosis, a term also used to describe the appearance of mucin around hair follicles as seen under the microscope. Mucins look like stringy clear or whitish goo and in the skin are mainly made up of hyaluronic acid (a normal component of the ground substance surrounding collagen in the dermis). Several other forms of mucinosis are described.
Alopecia mucinosa usually presents as slightly scaly bald patches in which the follicles are unusually prominent. Most common sites of involvement are the face, neck and scalp, but any part of the body may be affected.
There are basically three types of alopecia mucinosa; a primary and acute disorder occurring in children and adolescents (Pinkus type), a primary and chronic disorder occurring in people older than 40 years and a secondary disorder associated with benign or malignant skin disease. Urticaria-like follicular mucinosis is very rare.
What cause alopecia mucinosa?
Why alopecia mucinosa occurs is unknown, but it may have something to do with circulating immune complexes and cell-mediated immunity. What is known is that mucinous material deposits and accumulates in hair follicles and sebaceous glands to create an inflammatory condition that subsequently breaks down the ability of the affected follicles to produce hair.
What are the clinical features?
Early signs of the disease are the presence of grouped follicular papules (raised spots) that appear in reddened plaques or patches. These are usually 2-5 cm in diameter but can be larger. One or more lesions may be present from onset or a single lesion may develop to multiple lesions over a few weeks or months. Hair loss is common from the affected follicles. In the early stages, this is reversible i.e. the hair will grow back if the condition clears up. In more severe disease complete follicular destruction prevents normal hair growth even if the inflammatory skin disease is controlled.
|Clinical type||Differing features|
|Primary and acute||
|Primary and chronic||
|Urticaria-like follicular mucinosis||
What treatment is available?
There is no proven effective treatment for alopecia mucinosa. Usually primary and acute alopecia mucinosa occurring in children resolves spontaneously. Because there is a small chance of spontaneous resolution for other forms of the disease, the effect of treatment can be difficult to assess. Some treatments that have been tried with limited success include:
- Topical, intralesional and systemic corticosteroids
- Oral antibiotics such as minocycline
- Topical and systemic photochemotherapy (PUVA)
- UVA1 phototherapy
- Topical bexarotene 1% gel
Secondary alopecia mucinosa should be treated appropriately for the underlying skin disease, particularly if this is cutaneous T-cell lymphoma.