Causes of Excessive Body Hair, or Hypertrichosis
May be Congenital or Acquired Due to Injury, Illness or Drugs
Jul 23, 2009
‘Hypertrichosis’ is the medical term for excessive growth of hair on any part of the body in both men and women. It is not to be confused with ‘hirsutism’, which is the growth of facial hair in women.
Generalized Hypertrichosis – Excessive Hair Growth All Over the Body
In the most extreme types of hypertrichosis, the entire body is covered with hair; only the palms of the hands and the soles of the feet are spared. These disorders have a genetic origin and are very rare.
- During development in the womb, all human fetuses grow a coat of soft, fine hair called ‘lanugo’. This is normally shed before birth, but a mutation in the genes can cause it to be retained. These babies are unusually hairy at birth, and the lanugo continues to grow until the body is covered with long, silky silvery or grey hair. In most cases, the lanugo falls out as the child grows and only isolated patches are left by adulthood.
- In Ambras syndrome, in contrast, the thickness and extent of excessive body hair tends to increase with age. In some cases, the hair can reach a length of several tens of centimetres. People with Ambras syndrome may also have problems with their teeth and the shape of the bones of the face.
Patchy Excessive Body Hair
In other types of hypertrichosis, excessive body hair grows in patches. It can be congenital, or may be a consequence of damage to the skin, underlying health problems or treatment with certain medications. There are many causes, a few of which are listed here.
- Pigmented naevi (birthmarks or moles) often produce clumps of thick, dark hairs.
- Becker’s naevus is a larger area of pigmentation and coarse hairs on the shoulders and back, or occasionally the face, arms or legs. It usually first appears around the time of puberty, in boys more often than girls, and can increase in size over time. Although called a ‘naevus’, it is not a birthmark; the cause is unclear, though sunburn may be a factor.
- Children born with certain forms of spina bifida or other defects in the spine may have a hairy tuft on the lower back (a ‘faun tail’).
- Temporary hypertrichosis can occur on an arm or leg that has been in enclosed in a plaster of Paris cast.
- Occupational hypertrichosis is sometimes seen in workers such as porters whose job requires them to carry heavy loads on their shoulders. It results from repeated friction and pressure on the skin, which leads to inflammation; the resulting increased blood flow to the area may account for the excessive hair growth.
- Increased hair growth may occur on the hands or fingers following the removal of a wart, around burns on the skin, at the site of a vaccination, or surrounding an insect bite that has been scratched excessively. Again, the hypertrichosis may be due to localized inflammation.
- Increased body hair can be associated with a wide range of health problems, including porphyria, anorexia nervosa, hypothyroidism, malnutrition and cancer.
- Drugs that have been reported to cause hypertrichosis as a side-effect include prolonged courses of corticosteroids, psoralen (used in the treatment of psoriasis) and ciclosporin (an immunosuppressant given to transplant patients).
Excessive Body Hair Has Many Possible Causes
Some people are naturally more hairy than others. The term 'hypertrichosis' is used when the thickness and/or length of the body hair is excessive for the affected person’s age, ethnicity or gender. There are many possible causes; a doctor can advise on the diagnosis and possible treatments. For unwanted hair without any underlying medical cause, various methods of removal are available, some temporary and others permanent.
References
Fenton DA. Hair and Scalp Disorders. Medicine 2004; 32(12): 26–31.
Hypertrichosis.com. Accessed 23-07-09
Disclaimer
The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice.
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