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Unwanted hair remains one of the most frequent reasons for visiting a dermatologist. According to the statistics of the International Society of Aesthetic Plastic Surgery (ISAPS) for 2022, hair removal is one of the top three most popular non-surgical procedures for aesthetic correction. In 2022, unwanted hair removal procedures increased by 96% compared to 2018.

Not only healthy people but also those suffering from intense hair growth as a disease symptom may request the removal of unwanted hair. Excessive hair growth can be genetically determined due to various diseases and pathological conditions. There are two primary forms of excessive hair growth with different etiologies and clinical features: hirsutism and hypertrichosis.

In children's fairytales, you can often encounter negative heroines with hair on the chin or above the upper lip. Excessive hair growth in the male type in women is denoted by the term "hirsutism." It is often really accompanied by increased nervousness because the cause of pathological hair growth, in this case, are hormonal disorders that affect the psycho-emotional state of the patient — an increase in the level of androgens in the blood serum or increased sensitivity of the hair follicle to the action of androgens. Weakly colored down hairs transform into thick and pigmented terminal hairs on more extensive areas of the body — below the abdomen, on the inner surface of the thighs, around the nipples and sternum, above the sacrum, on the shoulders, as well as above the upper lip, on the chin and around sideburns. The most common cause of hirsutism is polycystic ovary syndrome. Other causes include late congenital adrenal hyperplasia, hyperprolactinemia, and thyroid disease [1].

In rarer cases, excessive hair growth occurs in androgen-independent areas, referred to as "hypertrichosis." Hypertrichosis can occur in both women and men and can be generalized or focal. Hereditary syndromes, somatic and oncologic diseases, and medications may cause hair growth in any area of the body more than the normal amount for people of a given age, race, and sex.

An example of a generalized congenital form of hypertrichosis is the "Werewolf syndrome," in which genetic mutations lead to dysfunction of proteins involved in hair follicle development. The entire body of such patients is covered with long vellus hair (Fig. 1), except for those areas where hair does not usually grow (palms, feet) [2].

Fig. 1. Pruthviraj Patil, an 11-year-old Indian boy who was born with hypertrichosis [2]

Focal congenital hypertrichosis in the lumbosacral region along the midline is called "Faun tail." Abnormal hair growth is a characteristic and reliable marker of spinal pathology: cutaneous manifestations occur in more than 50% of cases of spinal dysraphism — incomplete closure of the spinal canal of the spine (Fig. 2) [3, 4].

Fig. 2. (a) Clinical photograph showing faun tail (b) X-ray lateral view of lumbosacral spine of 8-year girl showing bony tail-like dorsal projection of dysplastic sacral segments (c) X-ray lumbosacral spine, AP view lateral view of 8-year girl showing absent coccygeal segments (d) magnetic resonance imaging of lumbosacral spine T2-Wi showing low lying conus with dural ectasia [4]

Generalized acquired downy hypertrichosis should also be a cause for concern. This abnormal hair growth is a paraneoplastic phenomenon and, in some cases, precedes the clinical symptoms of malignancies such as lung, colorectal and breast cancer.

The possible association of excessive hair growth with drug therapy should also be checked. Cases of hypertrichosis have been reported with antibiotics (streptomycin), anti-inflammatory drugs (benoxaprofen, corticosteroids), vasodilators (minoxidil, prostaglandin E1), diuretics (acetazolamide) and several other drugs.

With signs of hypertrichosis and hirsutism, the patient needs a medical examination and consultation with a family physician, dermatologist, endocrinologist, and oncologist. Determining the cause of abnormal hair growth will clarify the prospects for aesthetic correction of unwanted hair because, in most cases, the primary goal is to treat the underlying disease and eliminate the etiological factors that caused hirsutism or hypertrichosis.

References

1. Ansari R.T., Syed U., Riaz M., et al. Unveiling the spectrum: A cross-sectional study of hirsutism causes in women. Pak J Med Sci 2024; 40(4): 736-740.
2. Ashland Science Wiki. https://ashlandscience.shoutwiki.com/wiki/Hypertrichosis_(Werewolf_Syndrome)
3. Khurana K, Gaidhane S.A., Acharya S, Shetty N. Complex Closed Spinal Dysraphism Presenting As Cauda Equina Syndrome With Faun Tail Nevus. Cureus 2023; 15(10): e47396.
4. Satyarthee G.D., Mahapatra A.K. Faun tail associated with bony tail like projecting dysplastic sacral vertebral segments in natal cleft: Unique twin tails. J Pediatr Neurosci. 2015; 10(4): 411–412.