Alopecia Areata: What It Is, Causes, and How It Manifests

A round bald patch appears suddenly: the skin is smooth, without scars, looks normal on the outside, and at the edge short hairs are visible, narrowed at the base. This is typically how alopecia areata begins — a condition in which hair falls out in patches. Below is what is known about its nature, typical manifestations, and the boundaries of diagnosis.

What alopecia areata (patchy alopecia) is

Alopecia areata, or patchy alopecia, is a condition in which hair falls out in individual areas or across the entire body. Most often, several bald patches roughly the size of a coin appear on the scalp. Otherwise, people are generally healthy. In some cases, all hair on the head falls out (total alopecia) or on the body (universal alopecia). Hair loss may be temporary or permanent. The disease is not contagious and usually begins in childhood; about 0.15% of people are affected by it at any given time, and 2% of the population has ever encountered this problem.

Why it occurs: the autoimmune nature of the disease

It is believed that an autoimmune mechanism underlies it: the immune system mistakenly attacks and destroys healthy hair follicles. T-cell lymphocytes cluster around the affected follicles, causing inflammation and hair loss. Normally, follicles are protected from the immune system — this is called immune privilege; its disruption is considered the cause. The role of heredity is confirmed by familial cases: in identical twins, if one is affected, the probability for the other is about 50%. There are shared genetic risk factors with rheumatoid arthritis, type 1 diabetes, and celiac disease. Psychological stress, illness, pregnancy, or trauma may precede hair loss, but in most cases there is no obvious cause.

How alopecia areata manifests on the head

The typical onset is one or several bald patches from 1 to 4 cm. The spots are usually round or oval, the skin in them does not scar and looks normal on the outside, sometimes peach-colored. The area of hair loss may tingle or be slightly painful. At the edges, exclamation-mark hairs are visible — very short, 3–4 mm, narrowed at the base. Pitting on the nails is possible. If the process leads to complete hair loss, this often happens within 6 months of the first symptoms.

Alopecia on the beard

Alopecia areata most often affects the scalp and beard. The areas of hair loss here are just as smooth and rounded; sometimes erythema — redness of the skin — is visible in the area of baldness. Different zones may simultaneously lose hair and regrow it, so the picture changes over time.

Alopecia areata in women

The disease occurs in men, women, and children, but in women — more often than in men. A psychodermatological connection with impairments of mental well-being and self-esteem is discussed as a possible factor.

Diagnosis and when to see a doctor

The diagnosis is usually made based on the clinical picture. Trichoscopy helps to see uniform yellow dots, black dots, and exclamation-mark hairs. Sometimes a scalp biopsy is performed, and blood tests — to check for autoimmune conditions and thyroid problems. The prognosis varies: in more than 50% of cases with a sudden localized process, hair regrows within a year; with one or two bald patches, recovery is possible in up to 80% within a year; of those who lose all hair on the body, fewer than 10% recover.

• A bald patch or several, the skin beneath them smooth, without scars
• Short hairs, narrowed at the base, at the edge of the spot
• Tingling or mild soreness in the area of hair loss
• Pitting on the nails
• Hair loss on the beard, eyebrows, or other areas

Hair loss by itself is not a reason to call an ambulance; 103/112 — if, against the background of hair loss, there are signs of a life-threatening condition: sudden weakness or numbness of the face, arm, leg, difficulty speaking, chest pain, severe breathing difficulty.

This material is for reference: it explains what this condition is and how it looks, but does not replace a doctor's consultation — if you have any concern about your hair, see a dermatologist.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer