Alopecia areata

Alopecia (al-oh-PEE-shah) means hair loss. When a person has a medical condition called alopecia areata (ar-ee-AH-tah), the hair falls out in round patches. The hair can fall out on the scalp and elsewhere on the body.

Alopecia areata can cause different types of hair loss. Each of these types has a different name:

• Alopecia areata (hair loss in patches).
• Alopecia totalis (lose all hair on the scalp).
• Alopecia universalis (lose all hair on the body).

Not everyone loses all of the hair on the scalp or body. This happens to about 5 percent of people.

Hair often grows back but may fall out again. Sometimes the hair loss lasts for many years.

Alopecia is not contagious. It is not due to nerves. What happens is that the immune system attacks the hair follicles (structures that contain the roots of the hair), causing hair loss. This disease most often occurs in otherwise healthy people.

Source: https://www.aad.org

Signs, symptoms

If you have alopecia areata, you may have one or more of the following:

• Patchy hair loss: The problem often begins with 1 or more coin-sized, round, smooth, bare patches where hair once was. You may first notice the problem when you see clumps of hair on your pillow or in the shower.
  
  Hair loss occurs mostly on the scalp. But it can involve eyebrows, eyelashes, beards — any hair-bearing site. Patches vary in size.

• “Exclamation mark” hairs: Often, a few short hairs occur in or at the edges of the bare spots. These hairs get narrower at the bottom, like an exclamation mark.
  
  
• Widespread hair loss: With time, some patients go bald. Some lose all their body hair, too. This is not common. Also uncommon is a band of hair loss at the back of the scalp.

• Nail problems: Alopecia areata also can affect your fingernails and toenails. Nails can have tiny pinpoint dents (pitting). They also can have white spots or lines, be rough, lose their shine, or become thin and split. Rarely nails change shape or fall off.
  
  Sometimes nail changes are the first sign of alopecia areata.

Source: https://www.aad.org

Who get, causes

Who gets alopecia areata?

People can have this type of hair loss at any age. It often begins in childhood. Some patients with alopecia areata have a family member who also has the disease.

What causes alopecia areata?

Alopecia areata is an autoimmune disease. Autoimmune means that the body's immune system attacks the body. When alopecia areata develops, the body attacks its own hair follicles. A person's genetic makeup, combined with other factors, triggers this form of hair loss.

People with alopecia areata may have a higher risk for:

• Another autoimmune disease such as thyroid disease or vitiligo (patches of lighter skin appear)
• Asthma and allergies, mainly atopic dermatitis (more commonly called eczema) and hay fever (nasal allergies)
• Having relatives who have asthma, allergies, or an autoimmune disease such as type 1 diabetes

Source: https://www.aad.org