As with other autoimmune diseases, alopecia areata is linked to an increased risk of acquiring other autoimmune diseases as well, specifically systemic lupus erythematosus.

There are several ideas as to what exactly causes alopecia areata. The factor involving an individuals genetic makeup seems to be an important consideration since those who are affected by alopecia areata tend to have other family members who have been afflicted also.

Research suggests that a combination of certain genes make some people more prone to develop alopecia areata.

Alopecia areata, a common hair loss disease, is neither painful nor contagious. Although there is no specific reason for the onset and development of alopecia areata, there are factors in ones environment that may trigger the start of the disease. These factors may be biological or emotional. Some common causes and risk factors of alopecia areata are emotional stress, a family history and genetic predisposition to acquiring alopecia areata, chemicals and chromosomal disorders such as Down syndrome.

People who have thyroid diseases, asthma, allergic conditions, and other autoimmune diseases such as diabetes, vitiligo, and rheumatoid arthritis are also at risk to develop alopecia areata.

Some other causes for the development of alopecia include the following:

• Pregnancy

Pregnancy and child birth may cause excessive hair loss. During pregnancy, a womans hormone levels cause the hair to grow at a very high rate; however, upon giving birth, the hormone levels go back to normal and the hair goes into the resting phase of the hair growth cycle, causing excessive hair loss. This hair loss is natural and can be corrected in due time.

• Diseases of the thyroid glands

Thyroid diseases caused by either an overactive or underactive thyroid gland can also contribute to hair loss. A proper course of treatment may be undertaken to reverse this type of hair loss.

• Medical side effects

Medical treatments cause side effects including hair loss. Drugs that are used to treat diseases such as arthritis, depression, gout, high blood pressure, and heart problems have been known to cause hair loss in some patients.

• Birth control pills

The use of birth control pills can sometimes cause women to lose hair, specifically those women who have are more prone to hair loss (androgenic alopecia). If, upon taking birth control pills, hair thinning occurs, a woman can switch to another type of birth control pill.

• Infections

Certain scalp infections like ringworm can lead to hair loss. Once these infections are treated, the hair normally grows back.

• Stress

Stress can trigger alopecia areata. Stressful events such as major surgery or high fevers can trigger the start of genetic hair loss; and for individuals who have already started to lose hair, any stressful event can cause the hair loss to increase.

• Inadequate protein

Low protein can cause the body to shift the hair from the growth phase into the resting phase. If this happens due to low protein in the body, it is expected that hair shedding will occur after a period of two to three months. Hair loss brought about by inadequate protein may be reversed through proper diet and the intake of the prescribed amount of protein.

• Iron deficiency

A deficiency in iron can produce hair loss, and is common in women during pregnancy and menstruation.