Temporal Triangular Alopecia vs Alopecia Areata

Temporal triangular alopecia vs alopecia areata is one of the most useful scalp comparisons because the two can look similar at first: a localized patch of reduced hair density. But the pattern, timeline, and trichoscopy clues are different. Temporal triangular alopecia (TTA) is usually a stable, non-scarring, frontotemporal patch with vellus hairs throughout. Alopecia areata (AA) is an autoimmune patchy hair-loss disorder that more often shows active loss clues such as exclamation-mark hairs, black dots, and yellow dots.

Medical note: This article is for general education and does not provide personal medical advice. Do not assume every temple patch is alopecia areata, and do not start random treatment without a clear diagnosis. If the scalp is inflamed, painful, crusted, rapidly changing, or the diagnosis is unclear, start here: When to See a Doctor. For the broader rare-pattern roadmap first, start here: Rare & Congenital Hair Loss: Clues & Diagnosis.

Temporal triangular alopecia vs alopecia areata, stable temple patch, vellus hairs, exclamation-mark hairs, trichoscopy clues, and diagnosis. — TTA and AA can both look patchy at first, but the key difference is stable frontotemporal vellus-hair pattern in TTA versus active autoimmune patch clues in AA.

Key takeaways

Both conditions can look patchy: that is why they are commonly confused.
TTA is usually stable: it is a benign, non-scarring, non-progressive frontotemporal patch.
AA is usually an active autoimmune process: the patch may evolve and can show classic active-loss clues.
Trichoscopy is the practical separator: vellus hairs throughout the lesion with normal follicular openings favors TTA, while exclamation-mark hairs, black dots, and yellow dots support AA.
Location matters: TTA most often affects the frontotemporal scalp, usually on one side.
Treatment implications matter: mislabeling TTA as AA can lead to unnecessary treatment chasing.
Related on this site: Temporal Triangular Alopecia: A Stable Hairless Patch • Alopecia Areata: Patchy Hair Loss Signs & Treatment • Rare & Congenital Hair Loss: Clues & Diagnosis • Non-Scarring Alopecia • How Hair Loss Is Diagnosed.

Why these two get confused

At first glance, both can present as a localized patch of reduced hair. That is why the diagnosis cannot rest on “a patch” alone. The real question is whether the patch is a stable developmental/non-inflammatory pattern or an active autoimmune patch.

The core difference

Temporal triangular alopecia is usually a stable frontotemporal patch with vellus hairs preserved within the lesion. The scalp looks normal and there is no scarring or heavy inflammation.

Alopecia areata is an autoimmune patchy alopecia. The scalp is also usually non-scarring, but the patch is not a stable developmental pattern; it is an active hair-loss process and may show characteristic autoimmune clues on exam and trichoscopy.

Temporal triangular alopecia clues

Frontotemporal location, often unilateral
Triangular, oval, or spear-shaped patch
Normal-looking scalp skin
Stable course over time
Vellus hairs throughout the patch
Often noticed in infancy or childhood, though recognition may be later

Alopecia areata clues

Smooth patchy hair loss
Patch may appear on many scalp sites, not only the temple
May show exclamation-mark hairs, black dots, or yellow dots
The course may be more active or changing than classic TTA
Other autoimmune-pattern clues or nail findings may coexist in some patients

Trichoscopy: the practical separator

This is the most useful practical section. In TTA, trichoscopy usually shows normal follicular openings and vellus hairs throughout the lesion, sometimes with terminal hairs at the edge. In AA, the classic supportive clues are exclamation-mark hairs, yellow dots, black dots, and broken hairs rather than a stable field of vellus hairs.

How doctors check TTA vs AA

The workup usually begins with history + examination.

Where is the patch? frontotemporal only, or anywhere on the scalp
Has it been stable? or is it actively changing
Is the scalp skin normal? or are there other clues
Are vellus hairs present throughout?
Are AA markers present? exclamation-mark hairs, black dots, yellow dots

The practical goal is not to memorize every rare detail. It is to avoid mistaking a stable rare-pattern patch for an active autoimmune patch.

What to do now (practical plan)

Write down the location: temple/frontotemporal vs anywhere else.
Ask whether the patch is stable: long-term stability strongly favors TTA.
Check the scalp skin: TTA usually has normal-looking skin.
Use trichoscopy early: this is often the simplest way to separate the two.
Look for AA clues: exclamation-mark hairs, black dots, yellow dots, or active change.
Do not assume every patch needs AA treatment: classification matters first.

When to see a doctor

Rapidly changing patch rather than a stable long-term pattern
Scale, redness, pustules, pain, or inflammation
Multiple patches or broader scalp involvement
Unclear diagnosis between TTA, AA, and other patchy alopecias
Child with patchy loss and uncertain scalp findings

Start here: When to See a Doctor.

FAQ

What is the simplest difference between TTA and AA?

TTA is usually a stable frontotemporal patch with vellus hairs throughout. AA is an active autoimmune patch that more often shows classic AA trichoscopy clues.

Does TTA usually get bigger or move around?

Classic TTA is usually described as stable and non-progressive once established.

Why is trichoscopy so useful here?

Because it can show the vellus-hair pattern of TTA and the classic autoimmune clues of AA without jumping straight to unnecessary treatment.

Can TTA be present from early childhood?

Yes. It is often noticed in infancy or childhood, even if recognition comes later.

Does every temple patch mean TTA?

No. AA and other patchy alopecias still remain in the differential, which is why pattern and trichoscopy matter.

References (trusted sources)

Last updated: March 19, 2026.