Alopecia areata can strike anyone, and it can appear as early as childhood for both men and women. It’s characterized by patchy, sudden hair loss on your scalp, face, and possibly other areas of your body.
斑秃进行期诊断标准：有以下任何一项即可判定，1. 脱发时间半年以内。2. 秃发区日渐扩大或增多。3. 毛发松动，拉发试验阳性。4. 脱发区部分毛囊口有断发和“!” 样头发。
Diagnosis: Positive result determined based on any of below conditions. 1. Hair loss lasts over 6 months. 2. Hair loss areas enlarging or increasing. 3. Hairs become loosen. The pull test is positive. 4. There’re broken hair or “!”symbol hair in hair follicle.
Diffuse alopecia: it affects the scalp in a general distribution. This is in contrast to localised or focal alopecia, which is characterised by patchy hair loss.
Ophiasis alopecia areata: it causes hair loss in a band shape around the sides and back of your head. Occurs from hairline and spreads to centre. Usually, hair loss together with hair growth. Or hair grows very slowly. Even no new hairs grow for quite a while.
Pseudo alopecia areata is also known as Pseudopelade of Brocq (PBB) or Brocq Pseudopelade: The patches of hair loss present in PBB may be single or multiple. They are usually small, discrete, round or oval, and asymmetrical. The underlying skin is typically smooth, soft, and flesh-colored or white, with little, if any, inflammation.
Black dot ringworm of the scalp: Often occurs in children. Hairs don’t fall completely. Most hairs are broken. Left hair roots accompany with scale. And fungi could be detected easily.
Trichotillomania (TTM), also known as hair pulling disorder or compulsive hair pulling, is a mental disorder characterized by a long-term urge that results in the pulling out of one’s hair.This occurs to such a degree that hair loss can be seen. A brief positive feeling may occur as hair is removed Efforts to stop pulling hair typically fail. Hair removal may occur anywhere; however, the head and around the eyes are most common. The hair pulling is to such a degree that it results in distress.
The disorder may run in families. It occurs more commonly in those with obsessive compulsive disorder. Episodes of pulling may be triggered by anxiety. People usually acknowledge that they pull their hair. On examination broken hairs may be seen. Other conditions that may present similarly include body dysmorphic disorder, however in that condition people remove hair to try to improve what they see as a problem in how they look.
斑秃合并白癜风 ：约4-16%的斑秃可伴发白癜风 。
There’s about 4~16% alopecia areata associated with Vitiligo.