Excessive hair growth in children
Information on hypertrichosis and hair removal treatments
Pediatric hypertrichosis refers to excess hair growth in infants and children. All types of this disorder fall under various categories of hypertrichosis.
Generalised acquired hypertrichosis
The majority of such cases are more common among children.
Cerebral damage: Hypertrichosis may be caused by traumatic shock, head injury, transient pituitary or hypothalamic disturbance. They are too sporadic and nothing definite can be said about the cause. Involvement of hypothalamic factors has been suggested.
Infections like tuberculosis can cause transient hypertrichosis in children, primarily, on the face and limbs. AIDS affected patients often have hypertrichosis of the eyebrows, ears and eyelashes.
Malnutrition and starvation can cause vellus hypertrichosis in children as seen during the Irish potato famine in the nineteenth century. However, some experts dispute this belief.
Dermatomiositis in children can cause hypertrichosis mostly on the limbs and face. It is more common among male children and among patients with Mexican ancestry. The disorder resolves with steroid treatment.
Thyroid abnormalities resulting in hypothyroidism or hyperthyroidism can cause hypertrichosis. In children general hypertrichosis is more common. It is thought to be caused by the regional increase of acid mucopolysaccharides in myxedema.
Acquired porphyries in children due to exposure to the chemical hexachlorobenzene may cause generalized secondary hair growth in them. The hypertrichosis can be severe resulting in a monkey-like appearance in the children. Discontinuation of exposure to hexachlorbenzene resolves the disorder.
Drug induced hypertrichosis among children is common. The excess hair growth usually disappears after medication is stopped.
Phenytoin used for treating brain disorders produces hypertrichosis two to three months after use. In children, hypertrichosis disappears in 70 percent of cases with stoppage of medication. Cause of hair growth is not known but it is not due to androgen.
Streptomycin, used in children with tuberculosis, has been associated with hypertrichosis. But the effect may not be causal as tuberculosis itself produces hypertrichosis in the absence of this drug. Hair growth begins on the upper limbs and spreads to the back and lower limbs, sparing the neck, elbows and knees.
Cyclosporine is a major cause of hyoertrichosis in pediatric patients undergoing organ transplantation. Switching to FK 506 often decreases the hair growth.
Vasodilators like diazoxide are a well known cause of hypertrichosis in children. Diazoxide can cause hypertrichosis in 50 percent to 100 percent of children treated with it as against 1 percent in adults. Animal studies show that increased hair growth is due to greater proportion of follicles in the anagen stage. The growth is not androgen related.
Generalised congenital hypertrichosis
Congenital hypertrichosis lanuginosai is a rare inherited disorder where the lanugo hairs, which are shed during pregnancy, are retained after birth covering the entire body, except the palm and soles. However in the absence of a microscopic examination in most cases it is not confirmed if the hairs are lanugo or vellus. Many children shed most of their hair in late childhood but retain some excess hair throughout their lives. Some cases report associated dental abnormalities. This disorder can be autosomal inherited and also sporadic.
Brachmann de Lange syndrome: The children with the severe form of this syndrome acquire a distinct and easily recognizable appearance, which includes features like upturned nose, low set ears, bushy and convergent eyebrows, long eyelashes, low hairline and low forehead. The hair growth, which is extensive on the back and neck, is vellus. The children show mental and growth retardation like short upper limbs. Studies show it is an autosomal dominant inheritance and these tend to be less severe. But not all cases are explained by this kind of transmission.
Gingival fibromatosis with hypertrichosis: This is an autosomal condition in infancy where the hair growth on the face, trunk and eyebrows is accompanied by gingival hyperplasia. Fifty percent cases report mental retardation. The transmission can also be autosomal recessive. Some cases have shown de novo mutations.
Localized congenital hypertrichosis
Congenital pigmented hairy nevi are probably the most common cause of localized hypertrichosis in infants. The nevi are not indurated, are not raised by stroking and are pigmented. Surgery is done more to prevent the development of melanoma than for cosmetic reasons.
Faun tail: Faun tail is localized hair growth on the lower back caused by a spinal defect. Such growth is most worrisome when it is an indicator of underlying occult neural abnormalities. Fun tail usually appears in early infancy and occurs more in females. The female to male ratio is estimated 4:1. There may not be any neurologic problems in infancy but will eventually show up later. Early detection is important for effective treatment.
Hypertrichosis cubiti or hairy elbows: Here excess and symmetric hair growth is often seen on the elbows in infancy, which increases in childhood and resolves fully or partially in adolescence. Some believe the growth to be a nevoid abnormality and to some it is simply an exaggerated physiologic hair distributon. Many cases involved patients with short stature but association with hypertrichosis is not confirmed. The transmission mode is not clear with cases reporting autosomal dominant and recessive transmission as well as de novo mutation.