A long-standing, stable patch of finer hair at one temple can be temporal triangular alopecia. It is a non-scarring form of localised hair loss that is often recognised in childhood, although it may first be noticed in adult life. It should be distinguished from alopecia areata, traction and pattern hair loss before treatment is chosen.
The useful first step is an accurate diagnosis, with an explanation of which options are realistic for that particular patch. Ask about a diagnosis-led hair assessment before PRP, especially if earlier treatments have been selected without a clear account of what the condition is.
What does temporal triangular alopecia look like?
DermNet describes a triangular or spear-shaped patch in the frontotemporal scalp, usually on one side. Some patches are oval rather than perfectly triangular. Fine vellus hairs are usually present rather than the area being entirely devoid of follicles.
The patch typically remains stable and has no clinical inflammation or scarring. That history is important. A new, rapidly enlarging patch, redness, scaling, pain or loss of follicular openings needs assessment for other diagnoses rather than being labelled triangular alopecia from a photograph.
The condition is sometimes called congenital triangular alopecia, but not everyone has an obvious patch at birth. Recognition later in life does not necessarily mean a new disease has just started.
Why can it be mistaken for another condition?
Hairline location can make traction or androgenetic hair loss seem plausible. A smooth patch can also suggest alopecia areata. However, the history, shape and magnified hair findings may point in a different direction.
A treatment shown to help one type of hair loss cannot automatically be expected to help another. If the diagnosis is wrong, a technically well-delivered procedure may still be the wrong use of your time and money.
Bring older photographs if you have them. They can help establish whether the patch has changed over years and whether there is separate thinning elsewhere. A person can have a stable temple patch and an unrelated hair disorder at the same time.
What can trichoscopy show?
Trichoscopy is magnified examination of the scalp and hair. DermNet describes normal follicular openings with fine vellus hairs and normal terminal hairs at the edge in temporal triangular alopecia. Features typical of some other hair disorders may be absent.
The diagnosis is usually clinical, and a biopsy is not routinely necessary when the picture is clear. If the history or examination is atypical, the clinician may recommend further investigation or dermatology review. A remote photograph cannot always answer the same questions as an in-person scalp examination.
Ask the clinician to explain what they see and why it supports the diagnosis. The purpose of a magnified image is to clarify the decision, not simply to make a treatment package appear more technical.
Does the patch need treatment?
Treatment is not medically necessary in every confirmed case. Understanding that the condition is non-scarring and stable may be enough for some people. For others, its visible position has a meaningful cosmetic impact and deserves a thoughtful discussion.
DermNet notes that treatment is generally ineffective, while surgical excision for a small lesion or hair transplantation has been used in selected cases. Suitability depends on the diagnosis, age, patch and expectations. A description of an option is not a recommendation that everyone should have it.
If a medicine is discussed, ask about the evidence for this condition, the expected degree of change and what happens after stopping. A small change seen under magnification may not translate into the visible improvement you are hoping for.
What do we know about PRP here?
A published 2020 case report followed one person treated with five PRP sessions. Some change in fine hairs was seen, but the overall visible improvement was unsatisfactory and the response was transient. The report does not establish reliable or lasting benefit.
One case cannot tell us the chance of success, identify the best protocol or show that a treatment works better than observation. It also cannot prove that nobody could ever benefit. The honest conclusion is that this is a very small and uncertain evidence base, not a reason to sell a standard PRP course for the diagnosis.
Evidence in androgenetic alopecia should not be borrowed to promise the same response in temporal triangular alopecia. Similar-looking follicle miniaturisation does not establish that the two conditions respond identically. The diagnosis must remain central to the recommendation.
How should a treatment discussion be structured?
Start with the specific aim: reassurance, camouflage, a visible cosmetic change or management of another coexisting hair problem. Ask which part of that aim the proposed treatment is expected to address and how results would be assessed fairly.
Consistent photographs, lighting and hair positioning matter when judging a subtle change. Ask what would count as a worthwhile result, when to review it and when to stop an unhelpful course. A plan with an honest stopping point can be more valuable than an open-ended series of procedures.
Arrange an assessment that starts with the diagnosis if you would like the options explained. The appropriate clinician, appointment format, any separate investigation and complete fee should be confirmed for the individual enquiry. No treatment outcome can be guaranteed.
What should I bring?
Bring older photographs, a list of previous hair treatments and details of any new shedding, itching or scalp discomfort. Mention tight hairstyles or repeated tension, but do not assume that styling caused a patch that has been present and unchanged since childhood.
For parents, assessment should be age-appropriate and avoid unnecessary cosmetic procedures. A child's stable patch and an adult's cosmetic goals require different conversations. Specialist advice may be appropriate before considering treatment.
Your next step
A stable temple patch deserves a name before it receives an injection. Ask for a clear assessment and realistic options so that any next step matches the condition and your goals. Seek medical review for a changing, painful or inflamed patch rather than assuming the diagnosis remains the same.
Sources and evidence limits
DermNet: Temporal triangular alopecia. Clinical features, diagnosis and treatment overview.
Transient response to PRP: a 2020 case report. One patient, transient response and unsatisfactory overall cosmetic outcome. It cannot establish efficacy or an optimal protocol.
Prepared 3 November 2026. General patient information, not an individual diagnosis or treatment recommendation.