Alopecia areata
Alopecia areata (pronunciation: al-oh-PEE-shah air-ee-AH-tah) is a condition that causes hair to fall out in small patches, which can be unnoticeable. These patches may connect, however, and then become noticeable. The condition develops when the immune system attacks the hair follicles, resulting in hair loss. Sudden hair loss may occur on the scalp and other parts of the body. The condition can result in total hair loss, known as Alopecia totalis, and it can prevent hair from growing back. When hair does grow back, it's possible for the hair to fall out again. The extent of hair loss and regrowth varies greatly from person-to-person.
Etymology
The term "alopecia" comes from the Greek word "alopex" which means fox. Foxes are known to shed their fur twice a year. "Areata" is a Latin word that means occurring in patches or limited areas.
Symptoms
The main symptom of alopecia areata is hair loss. Hair usually falls out in small patches on the scalp. These patches are often several centimeters or less. Hair loss might also occur on other parts of the face, like the eyebrows, eyelashes, and beard, as well as other parts of the body. Some people lose hair in a few places. Others lose it in a lot of spots.
Causes
Alopecia areata is an autoimmune disease. An autoimmune disease develops when the immune system mistakes healthy cells for foreign substances. Normally, the immune system defends your body against foreign invaders, such as viruses and bacteria. If you have alopecia areata, however, your immune system mistakenly attacks your hair follicles. Hair follicles are the structures from which hairs grow. The follicles become smaller and stop producing hair, leading to hair loss.
Related Terms
- Alopecia totalis: Complete loss of hair on the scalp.
- Alopecia universalis: Complete loss of hair on the entire body.
- Autoimmune disease: A disease in which the body's immune system attacks healthy cells.
- Hair follicle: The part of the skin which grows hair by packing old cells together.
External links
- Medical encyclopedia article on Alopecia areata
- Wikipedia's article - Alopecia areata
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