There are three stages of the hair cycle: the anagen phase (hair growth), the catagen phase (hair follicle death), and the telogen phase (hair shedding). If the anagen phase increases beyond what is normal, that region of the body will experience excessive hair growth. Diagnosis
Hypertrichosis is diagnosed clinically by the occurrence of hair in excess of what is expected for age, sex, and ethnicity in areas that are not androgen-sensitive. The excess can be in the form of excessive length or density and may consist of any hair type (lanugo, vellus, or terminal). Management
There is no cure for any congenital forms of hypertrichosis. The treatment for acquired hypertrichosis is based on attempting to address the underlying cause. Acquired forms of hypertrichosis have a variety of sources, and are usually treated by removing the factor causing hypertrichosis, e.g. a medication with undesired side-effects. All hypertrichosis, congenital or acquired, can be reduced through hair removal. Hair removal treatments are categorized into two principal subdivisions: temporary removal and permanent removal. Treatment may have adverse effects by causing scarring, dermatitis, or hypersensitivity.Temporary hair removal may last from several hours to several weeks, depending on the method used. These procedures are purely cosmetic. Depilation methods, such as trimming, shaving, and depilatories, remove hair to the level of the skin and produce results that last several hours to several days.
Hypertrichosis is an abnormal amount of hair growth over the body. The two distinct types of hypertrichosis are generalized hypertrichosis, which occurs over the entire body, and localized hypertrichosis, which is restricted to a certain area. Hypertrichosis can be either congenital (present at birth) or acquired later in life. The excess growth of hair occurs in areas of the skin with the exception of androgen-dependent hair of the pubic area, face, and axillary regions.Several circus sideshow performers in the 19th and early 20th centuries, such as Julia Pastrana, had hypertrichosis. Many of them worked as freaks and were promoted as having distinct human and animal traits. Classification
Two methods of classification are used for hypertrichosis. One divides them into either generalized versus localized hypertrichosis, while the other divides them into congenital versus acquired. Congenital
Congenital forms of hypertrichosis are caused by genetic mutations, and are extremely rare, unlike acquired forms. Congenital hypertrichosis is always present at birth. Hypertrichosis lanuginosa
Congenital hypertrichosis lanuginosa can be noticed at birth, with the infant completely covered in thin lanugo hair. In normal circumstances, lanugo hair is shed before birth and replaced by vellus hair; however, in a person with congenital hypertrichosis lanuginosa, the lanugo hair remains after birth. The palms of the hands, soles of the feet, and mucous membranes are not affected. As the person ages, the lanugo hair may thin, leaving only limited areas of hypertrichosis. Generalized hypertrichosis
Congenital generalized hypertrichosis causes males to exhibit excessive facial and upper body hair, whereas women exhibit less severe asymmetrical hair distribution.