What Causes Hair Loss (Alopecia)?

Alopecia, commonly known as baldness or hair loss, can be an embarrassing problem for both men and women. But what causes it?

While some causes can be unique to either men or women, there are a number of causes common to both genders. Obvious causes of hair loss in both men and women are heredity, stress and certain health conditions. Hereditary hair loss is called androgenetic alopecia, and is the most common form of hair loss. It can be passed down to you through either your mother or your father. If you grow miniaturized hair follicles in place of the lost normal ones, the cause of your hair loss is likely due to heredity and can be diagnosed via biopsy of the scalp. Usually related to stress, the second most common cause of hair loss is called telogen effluvium. This condition, in which hair follicles enter the dormant, or telogen, phase in the growing cycles earlier than normal, can be triggered by stress, after a major surgery or pregnancy, or after extreme weight loss has occurred. It can also be caused by certain medications including NSAIDs, beta-blockers and anti-depressants.

Cytostatic cancer treatment drugs, or chemotherapy, may cause a hair loss condition known as anagen effluvium. It can affect either men or women, and occurs very rapidly. Other health-related causes of alopecia include radiation therapy for cancer; anemia, which occurs when you are not producing enough red blood cells; lupus, an autoimmune disease that affects more women than men, but can develop in either gender; hypothyroidism, which occurs when your body does not produce enough parathyroid hormone and, again, affects more women than men; skin and scalp conditions like dandruff, psoriasis and fungal infection; and alopecia areata, an autoimmune disorder thought to be triggered by stress or illness. Alopecia areata results in smooth, circular bald patches and can occur on the scalp, legs or eyebrows. 

Male pattern baldness is simply a form of androgenetic alopecia. In most cases, hair on the crown of the head starts to thin after the hairline has already begun to recede. The cause is hereditary, and either your mother or father can pass on the gene which predisposes you to this condition. The cause may also include a hormonal component. 
Alopecia that occurs in women may occur after pregnancy, but is basically a form of telogen effluvium induced by pregnancy-related stress. Another type of hair loss that occurs typically, but not exclusively, in women is known as traction alopecia. The cause of traction alopecia is excessive styling of the hair, including tight corn rows, braids and pony tails. When the hair is pulled too tightly over a long period of time, the hair follicles and dermal papilla become damaged. A hair transplant is the most common treatment sought for this condition. 

Anyone suffering from hair loss should consult their physician to determine the exact cause of the alopecia and what type of treatment, if any, is necessary.