Baldness is a skin condition that occurs when hair either falls out or fails to grow in places of the body where it is expected to be. There are many types of baldness, each of which has a different set of etiologies.
The most common type of baldness is called male pattern baldness. It occurs to some degree in up to 2/3 of men and is related to one’s genetic background. This generally begins with thinning at the temples and around the face, as well as the crown of the head. It generally progresses to include much of the head. This type of hair loss is related to an excess of dihydrotestosterone, which is made from testosterone through the use of the enzyme 5-alpha reductase.
Female pattern baldness is felt to be due to a general decline in estrogen with age and is seen as a diffuse hair thinning or as a widening of the part in the hair. Women with conditions such as hypothyroidism can have thinning hair. Fungal infections of the skin can result in damage to and loss of healthy hair follicles. Treating the fungal infection often improves the hair loss.
Autoimmune conditions can lead to the immune system attacking parts or all of the hair. One condition is known as alopecia areata and is seen as circular patches of hair loss, particularly on the scalp. This kind of condition can affect the whole body, resulting in a complete loss of hair in a condition called alopecia areata universalis.
The treatment of baldness depends upon the cause of the condition. Treatment of alopecia areata involves the use of agents that block the immune response. The treatment can be locally applied or given internally. In other types of baldness, such as those due to fungal infections, treating the infection can improve the status of the hair.
Medications for other types of baldness generally attack the transformation of testosterone to dihydrotestosterone, a hormone that mixes with the sebum in the hair follicles and damages the follicle, resulting in hair loss. Finasteride (Propecia) and minoxidil (Rogaine) are marketed for hair loss and work by inhibiting the 5-alpha reductase enzyme so that less dihydrotestosterone is produced. These medications seem to work better when the hair loss is not extreme.
Some men resort to treatments such as hair transplants that take plugs of hair and skin from healthy parts of the hair and transplant the plugs to the bald areas of the hair. This obviously works best in men who have considerable hair left from which to take the transplants from.