Acquired hypertrichosis lanuginosa is also referred to as ‘hypertrichosis lanuginosa acquisita’, 'paraneoplastic hypertrichosis lanuginosa' and ‘malignant down’.
What is acquired hypertrichosis lanuginosa?
Lanugo hairs are normally present from the third month of fetal life through to the end of gestation and are shed almost completely before birth. Acquired hypertrichosis lanuginosa is a very rare condition characterised by the rapid growth of long, fine, lanugo-type hair particularly around the eyebrows, forehead, ears and nose in adulthood. It is similar to congenital hypertrichosis lanuginosa (see hypertrichosis) except that it appears later on in life, and in most cases is associated with an underlying cancer.
Although the face is the most common area affected by acquired hypertrichosis lanuginosa, some patients have extensive involvement that includes the trunk, axillae and extremities. Palms, soles, scalp and pubic regions tend to be spared. The hair is fine, thin and unpigmented.
Other associated symptoms include glossitis, a bumpy enlarged tongue, disturbances of taste and smell, and, less frequently, diarrhoea, weight loss, and enlarged lymph glands. Other paraneoplastic skin conditions that may also occur with acquired hypertrichosis lanuginosa include acquired ichthyosis, acanthosis nigricans, and tripe palms.
What is the cause of acquired hypertrichosis lanuginosa?
The cause of hypertrichosis lanuginosa acquisita is unknown but it is thought to be in response to hormones or substances released by the tumour. Most cases of acquired hypertrichosis lanuginosa are associated with an internal malignancy. The most frequently associated cancers include lung, breast and uterine cancers, colorectal cancer, lymphoma, and bladder cancer. The hypertrichosis most often occurs late in the course of the cancer, however in some cases it may be the presenting sign of a tumour and can appear up to 2 years prior to diagnosis of cancer.
Less commonly, acquired hypertrichosis lanuginosa is associated with non-malignant disease such as malnutrition associated with anorexia nervosa, hyperthyroidism, and acquired immune deficiency syndrome (AIDS) associated with human immunodeficiency virus infection (HIV). It may also be a side effect of drugs such as ciclosporin, phenytoin, interferon, spironolactone, and corticosteroids.
Malignant forms of acquired hypertrichosis lanuginosa look exactly the same as when associated with non-malignant diseases or drugs. Hence it is important that when non-malignant causes have been ruled out, patients undergo comprehensive screening and careful monitoring to detect any associated cancer.
What is the treatment for acquired hypertrichosis lanuginosa?
The main goal of treatment is to treat the underlying cancer. Because acquired hypertrichosis lanuginosa typically occurs late in the course of the malignancy, the overall prognosis is poor. However, regression of hair growth is known to occur if the tumour is treated or removed.
There is no specific treatment for acquired hypertrichosis lanuginosa. To improve the cosmetic appearance the following hair removal techniques may be used: