Alopecia Areata: Patchy Hair Loss Signs & Treatment

Alopecia areata is a common cause of patchy hair loss. It happens when the immune system targets hair follicles, leading to smooth, round or oval bald patches—most often on the scalp, but it can also affect eyebrows, eyelashes, and the beard area.

Medical note: This article is for general education and does not provide personal medical advice. For the full roadmap, start here: Hair Loss (Complete Guide).

Alopecia areata: smooth patchy hair loss signs and when to seek care. — Alopecia areata usually causes smooth, round patches of hair loss without heavy scale. See a clinician if loss is widespread or the scalp is painful or inflamed.

What is alopecia areata?

Alopecia areata (AA) is an autoimmune form of hair loss where the immune system attacks hair follicles. It is usually non-scarring, meaning follicles are typically preserved, so regrowth is possible in many cases.

On our site, AA belongs under: Non-Scarring Alopecia (Overview) and the big picture map: Types of Hair Loss.

What it usually looks like

Smooth, round or oval bald patches
Sudden onset over days to weeks
Often no heavy scale and no “broken hair” appearance
Can affect scalp, eyebrows, eyelashes, beard
Hairline band pattern (ophiasis) can happen in AA: Ophiasis Alopecia Areata

Note: Hair loss can also appear more widespread (many patches) or rarely involve most of the scalp/body. If you’re seeing mainly diffuse shedding without clear patches, read: Telogen Effluvium (Hair Shedding).

Why it happens (causes & triggers)

Alopecia areata is autoimmune. The exact cause is not fully understood, but genetics and immune regulation play a role. Some people notice onset after stress or illness, but many cases occur without a clear trigger.

Conditions that can look similar

Patchy hair loss has a few important “look-alikes.” The right next step depends on what the scalp looks and feels like:

Fungal infection (tinea capitis): more likely if there is scaling, black dots, broken hairs, or a child is affected.
Trichotillomania: irregular patches with hairs of different lengths (hair pulling).
Traction alopecia: hair loss along edges/temples from tight styles.
Scarring alopecia: shiny smooth skin, loss of follicle openings, pain/burning → evaluate promptly.

If your main concern is gradual patterned thinning (temples/crown or widening part), see: Androgenetic Alopecia (Pattern Hair Loss).

How it’s diagnosed

Diagnosis is usually based on history and scalp examination. Clinicians may look for typical patch patterns and characteristic short “exclamation point” hairs near the edges of patches. In uncertain cases, they may consider additional evaluation.

Treatment options (overview)

Treatment depends on the amount of hair loss, how fast it’s progressing, and whether eyebrows/beard are involved. Options may include topical therapies and in-office treatments. Your clinician can help choose a plan based on severity and risks.

For general treatment concepts and expectations, see:

Prognosis & what to expect

Many people with limited patchy alopecia areata experience regrowth, but relapses can occur. If hair loss is extensive or rapidly progressing, it’s best to seek evaluation early.

When to see a doctor (don’t wait for these)

Rapidly expanding patches or many new patches
Scalp pain, burning, pustules, thick crusting
A child with patchy loss + scale (rule out tinea capitis)
Shiny smooth areas or loss of follicle openings (possible scarring)

Read: When to See a Doctor.

FAQ

Is alopecia areata contagious?

No. Alopecia areata is autoimmune and is not contagious.

Will the hair grow back?

Regrowth is possible in many cases, especially with limited patchy disease, but relapses can occur.

How is it different from telogen effluvium?

Alopecia areata often causes patchy hair loss. Telogen effluvium usually causes diffuse shedding. See: Telogen Effluvium.

How is it different from pattern hair loss?

Pattern hair loss is typically gradual and follows a pattern (temples/crown or widening part). See: Androgenetic Alopecia.

References (trusted medical sources)

Last updated: February 26, 2026.