Temporal Triangular Alopecia in Adulthood

You don’t need a geometry lesson to know when your hair is falling out in triangular-shaped patches. If that sounds familiar, you could be dealing with temporal triangular alopecia (TTA), also known as congenital triangular alopecia (CTA).

Temporal triangular alopecia often develops in childhood, though it can start later in life. It typically only affects one side of the scalp, but about 20 percent of people see hair loss on both sides of their hairline.

Below, we’ll discuss what TTA is exactly and the signs and symptoms you might notice if you’re affected by this type of hair loss. We’ll also explain what causes temporal triangular alopecia, along with steps you can take to treat it and restore your hairline.

Temporal triangular alopecia is an uncommon form of non-scarring alopecia (alopecia is hair loss). It’s characterized by a triangular patch of hair loss, usually around the frontotemporal scalp (the front of your scalp or hairline, above the outer end of the eyebrows).

Within this patch of the dermis, healthy hair follicles for normal terminal hair (the type of hair on your head, body or eyebrows) are replaced by vellus hair follicles. Vellus follicles are thin and miniaturized, so they’re less able to grow the terminal hairs that create a normal hair density.

Temporal triangular alopecia (sometimes called temporal balding) is most common in infants and children. But some folks also develop this form of hair loss as adolescents or during adulthood.

Unlike many other types of hair loss, temporal triangular alopecia is non-progressive, meaning it generally doesn’t get more severe over time. And unlike scarring alopecia, TTA doesn’t leave behind scars.

Temporal triangular alopecia is pretty rare. Research suggests that just 0.11 percent of the population — or around one in every 1,000 people — have the condition.

Having said that, it can sometimes be hard to detect, and some people don’t notice it. So temporal triangular alopecia may actually be under-reported, meaning more people might have it.

Experts have been aware of temporal triangular alopecia for over a century — it was first described in 1905. But more than 100 years later, the precise causes of temporal balding still aren’t completely understood.

Some researchers think this form of alopecia is congenital, meaning people have it from the time they’re born. However, many cases of temporal triangular alopecia seem to start later in life (at least in terms of noticeable symptoms).

Based on past cases, other experts have suggested that temporal triangular alopecia may be caused by abnormal or incomplete development of the outermost skin layer known as the epidermis.

Risk Factors for Temporal Triangular Alopecia

Although the precise cause of temporal triangular alopecia isn’t known, experts in trichology (hair and scalp) have identified case reports where certain disorders and syndromes often occur at the same time as this condition.

These include:

• Abnormalities affecting bones or teeth

• Certain types of birthmarks or skin pigmentation issues

• Neurological disorders, such as epilepsy or Dandy-Walker syndrome (DWS)

• Hypospadias (abnormal development of the urethral opening in boys)

• Dysaesthesia (an abnormal sense of touch) in hairless areas

• Leukonychia (white discoloration affecting the nails)

• Recurrent bronchiolitis (lung infection in young children)

• Down syndrome and other forms of intellectual disability

• Woolly hair nevus (coiled, lightened hair)

• Hydronephrosis (swelling of the kidneys)

• Congenital heart diseases and defects

• Congenital hip dislocation (CHD)

• Iris nevi (freckles on the eyes)

• Klippel-Trenaunay syndrome

• Noonan syndrome with multiple lentigines

• Pai syndrome

• Phakomatosis pigmentovascularis (PPV)

• Turner syndrome

• Spina bifida

• Aplasia cutis

Those with one or more of the above disorders or syndromes could have a higher risk of temporal triangular alopecia. If you notice signs of hair loss or a clear patch of alopecia around the frontotemporal region of your scalp, talk to a healthcare provider sooner than later. 

Temporal triangular alopecia and androgenetic alopecia (the clinical term for male pattern baldness) can both lead to a receding hairline or a similar pattern of hair loss around the temporal region. So it’s easy to mistake one type of hair loss for the other. 

But temporal triangular alopecia and male pattern hair loss aren’t the same, meaning treatments for one form of hair loss may not help with the other. 

Below are five key differences between temporal triangular alopecia and male pattern baldness.

1. DHT Doesn’t Cause Temporal Triangular Alopecia

Male pattern baldness happens when the hormone dihydrotestosterone (DHT) attaches to receptors in your scalp, causing hair follicles to shrink (known as hair miniaturization).

Currently, there’s no high-quality evidence to suggest that DHT causes temporal triangular alopecia or that men with this type of frontotemporal hair loss have higher DHT levels than average.

The point is, medications that target DHT, like our topical finasteride & minoxidil spray, probably won’t be very helpful for temporal balding. But it’s great for male pattern baldness.

2. Male Pattern Baldness Typically Causes An Even Receding Hairline

Although it’s fairly common to have some asymmetry in your hairline, most guys with male pattern hair loss notice hairline recession that’s roughly the same on the left and right sides.

On the other hand, temporal hair loss is often unilateral, meaning it might show up on one side of your hairline but not the other.

3. Temporal Triangular Alopecia Is Usually Diagnosed Early in Life

Male pattern hair loss is more common in older men, as the effects of DHT can accumulate over time and harm hair follicles. By their 40s, around half of all men are affected.

In contrast, temporal triangular alopecia is usually diagnosed early in life. Most people are diagnosed as children, typically between three and nine years of age. However, it can (and occasionally does) develop in adults.

4. Temporal Triangular Alopecia Typically Only Occurs Near the Hairline

Male pattern baldness varies in severity, from a receding hairline to a bald patch around the crown to near-total baldness. The severity of hair loss is measured using the Norwood Scale.

Meanwhile, temporal triangular alopecia almost always affects areas near the hairline, like the temples or frontal scalp.

5. Temporal Triangular Alopecia Affects Men and Women

Though pattern hair loss affects both men and women, it’s more common in men. This might be because they generally have higher levels of testosterone and other androgens (male hormones) like DHT, which affects the hair growth cycle.

Temporal triangular alopecia doesn’t favor either gender — it happens to men and women at roughly the same rate.

It can be easy to mistake temporal triangular alopecia for other types of hair loss, including male pattern baldness and the more patchy alopecia areata. But temporal balding has some unique signs and symptoms that set it apart.

Temporal triangular alopecia symptoms include:

• A distinct triangular patch. There’s a distinct triangular patch on the hairline, with the point of the triangle facing toward the middle of the head. These patches are sometimes called lesions.

• Rounded top of patch. The patch shape might also be rounded at the top or described as “lancet-shaped.” These lesions are typically on the temporal hairline, but in rare cases, they’re seen on the occipital hairline (on the back of the head).

• Vellus hairs. These areas of hair loss may feature small vellus hairs — very fine hairs sometimes called peach fuzz.

• Pain or discomfort. There’s usually no physical discomfort associated with this type of hair loss, but some patients report dysesthesia (a condition where pain or discomfort on the lesion happens in response to little or no stimuli).

Another thing to note is that the patches may be very noticeable or barely visible at all.

If you’re worried you might be developing triangular temporal alopecia as an adult, one of the first things to do is talk to a healthcare provider.

Because triangular temporal hair loss isn’t common, your provider might suggest seeing a dermatologist (a doctor who specializes in the skin, hair and nails) or a trichologist (someone specializing in the scalp). 

To diagnose triangular temporal alopecia, a dermatologist will discuss your symptoms, perform a physical exam and carefully inspect your scalp. 

A skin biopsy isn’t typically needed, but your provider may want to look at the skin under a microscope (what’s known as histopathology) with a trichoscopic or dermoscopic device.

They might use something called a polarized handheld dermatoscope, which checks hair follicles for signs of this type of hair loss. This can help with a differential diagnosis — a fancy way of saying they’ll figure out which form of hair loss you have.

When diagnosing temporal alopecia, the exam (called dermoscopy or trichoscopy) looks for normal hair follicular openings with vellus hairs on the lesion and terminal hairs on its edge.

There shouldn’t be exclamation mark hairs, yellow or black dots, scarring or inflammation, all of which point to other types of hair loss.

Since triangular temporal alopecia isn’t a result of too much DHT, hair loss medications like finasteride don’t stop this form of hair loss or produce hair regrowth in the affected areas.

There’s also only very limited evidence that topical minoxidil offers benefits for this form of localized alopecia. (We offer this over-the-counter medication as minoxidil foam and minoxidil liquid solution to treat several common types of hair loss.)

In other words, the usual medications for hair loss in men may not be helpful if you have a thin, triangular hairline due to temporal triangular alopecia.

Hair-Thickening Products

Other hair loss treatments like volumizing shampoo, volumizing conditioner or our thickening shampoo with saw palmetto won’t be a permanent fix.

Still, they can make the hair you have look temporarily thicker and more voluminous to help mask some of the sparseness.

Surgery

Sometimes, the lesion can be removed through surgical excision. 

Currently, the most effective treatment for triangular alopecia is hair transplant surgery. This procedure involves surgically removing healthy hair follicles from the back and sides of the scalp and relocating them to the hairline.

A hair transplant doesn’t regrow hair per se — it’s kind of like moving chairs to the kitchen when guests come over. You’ll have more hairs where you need them and fewer where you don’t, ultimately making your hair appear fuller.

Hair transplantation can vary in price and complexity based on the severity of your hair loss and various other factors. When it’s performed by a skilled surgeon, it can “fill in” empty areas of your hairline and give you a natural-looking pattern of hair growth. 

Our guide to hair transplants goes deeper into hair restoration surgery, including the costs, benefits and potential side effects. 

Temporal triangular alopecia can take a serious toll on your hairline, causing a triangular patch of hair loss on one or both sides of the head.

This type of hair loss is very easy to mistake for male pattern baldness or other conditions like alopecia areata or trichotillomania (hair-pulling disorder).

There are a few things you’ll want to keep in mind if you think you (or a loved one) might be developing temporal triangular alopecia:

• First, it’s important to talk to a healthcare provider. A dermatology specialist can look at your scalp and let you know if you have temporal triangular alopecia or a more common type of hair loss.

• Second, most hair loss medications aren’t effective. If you have temporal triangular hair loss, taking a DHT-blocking medication like finasteride probably won’t have any effect on your hair density — so triangular alopecia treatment can be tricky.

• Third, you aren’t to blame. Although experts aren’t yet fully sure what causes incidences of triangular hair loss, there’s no scientific evidence suggesting that the way you care for your hair has any effect.

Not sure if you have temporal triangular alopecia, male pattern baldness or another type of hair loss like alopecia areata? Do an online hair loss consultation on our telehealth platform to figure out what could be causing your hair loss and explore options for promoting healthy hair growth.

You can also find out more about dealing with hair loss in our guides to alopecia types and the best ways to treat them and medications that could make your hair fall out.