A child with patchy scalp hair loss and a parent who is afraid, looking for answers, presents a specific clinical challenge. The differential is different than it would be in an adult. The history is harder to obtain. The presentations overlap in ways that can send a workup in the wrong direction. And the consequences of delay, particularly with tinea capitis, can mean permanent scarring before anyone realizes the diagnosis was wrong.
Pediatric hair loss is a distinct subspecialty of trichology, not an afterthought. The most common conditions affecting children's hair, tinea capitis, alopecia areata, and telogen effluvium, each have mechanisms, trichoscopic signatures, and treatment considerations that differ meaningfully from their adult counterparts, or that simply don't have adult counterparts at all. Understanding those differences is part of practicing competently in this space.
The 2024 and 2025 literature has added clarity to how we diagnose, what we use to do it, and what treatments are now available for the most treatment-resistant pediatric cases. This post breaks down what practitioners need to know.
The Pediatric Differential Is Different
In adults, the most common causes of hair loss are androgenetic alopecia, telogen effluvium, and alopecia areata, in roughly that order. In children, that hierarchy shifts substantially. Tinea capitis is the most common cause of patchy hair loss in prepubertal children, particularly those under age 10. Androgenetic alopecia, while it does exist in adolescents, is rarely the explanation for hair loss in a 6-year-old. Assuming otherwise can delay the correct diagnosis by months.
A 2025 review published in the Australasian Journal of Dermatology proposed a structured clinical algorithm specifically for pediatric hypotrichosis (hair loss or sparse hair in children), designed to guide clinicians through a diagnostic pathway using the forced hair pull test and trichoscopy to differentiate the major categories: infectious alopecia, immune-mediated alopecia, hair shaft structural disorders, non-scarring acquired alopecia, and congenital conditions. The framework is significant because it formalizes what experienced trichologists have known practically — that the diagnostic logic for a child is not simply adult logic applied to a smaller patient.
The algorithm the authors propose starts with a core question that guides the entire workup: is this scarring or non-scarring? That determination, made through careful scalp examination, shapes everything that follows. In a child with patchy hair loss, failure to rule out an active fungal infection before treating for alopecia areata can allow tinea capitis to progress toward kerion formation and permanent follicular damage, something that is entirely preventable with the right diagnosis.
Tinea Capitis: The Diagnosis That Gets Missed
Tinea capitis is a dermatophyte infection of the scalp and hair follicle. In the United States, roughly 90–95% of cases are caused by Trichophyton tonsurans, an anthropophilic organism that spreads person-to-person through direct contact, fomites, and household transmission. The organism is particularly prevalent among school-age children between 3 and 10 years, with higher incidence documented in Black and Latino children, and in the Southern United States. Pediatric cases are a pediatric disease; tinea capitis in adults is relatively uncommon, which is part of why it sometimes escapes consideration in practitioners who haven't worked extensively with children.
The clinical presentations of tinea capitis are not uniform, and that variability is where diagnoses get missed. The classic presentation is patchy alopecia with scaling, but the "black dot" pattern, where hairs break off at the scalp surface leaving dark stubs visible in the follicle openings, is characteristic of T. tonsurans endothrix infection and should be recognized immediately. A "grey patch" pattern can mimic seborrheic dermatitis so closely that practitioners treat the wrong condition for months. Vesiculopustular presentations can be confused with bacterial folliculitis. And kerions, the boggy, inflammatory, sometimes purulent plaques that develop from intense host immune response to the fungus, are often misidentified as bacterial abscesses and managed with antibiotics alone, delaying antifungal treatment and allowing scarring to progress.
A kerion is not a bacterial infection. It is an intense inflammatory response to dermatophyte antigen, and it requires systemic antifungal therapy, not antibiotics. Incision and drainage is contraindicated. Short-course corticosteroids may be added to reduce inflammation, but the antifungal is the primary treatment. Left untreated or inadequately treated, kerions cause permanent scarring alopecia in children — a completely avoidable outcome. If you encounter a child with a boggy, tender scalp mass and hair loss, culture it before treating it as anything else.
Treatment requires systemic antifungals. Topical agents do not penetrate the follicle sufficiently to eradicate tinea capitis. For T. tonsurans specifically, terbinafine has demonstrated superior cure rates to griseofulvin in multiple head-to-head trials, with a shorter treatment duration of 2–4 weeks versus 6–8 weeks for griseofulvin. The AAP currently recommends terbinafine as the first-line treatment for Trichophyton species infections. Household contacts and pets should be evaluated concurrently, as reinfection from untreated sources is common.
Distinguishing Tinea Capitis from Alopecia Areata: The Trichoscopy Problem
Here is where pediatric diagnosis gets genuinely complicated. Tinea capitis and alopecia areata can look nearly identical to the naked eye. Both present with patchy, circumscribed areas of hair loss. Both can show hair loss without obvious scarring on surface examination. Both can occur at the same age range. A missed tinea capitis treated as alopecia areata gets immunosuppressants and no antifungal; the infection spreads and scars. A missed alopecia areata treated as tinea capitis gets antifungals that do nothing while the immune attack on the follicle continues unchecked.
A 2025 study in Pediatric Dermatology presented a novel diagnostic supplement to standard trichoscopy: ultraviolet-induced fluorescence dermoscopy (UVFD). Standard polarized dermoscopy can reveal characteristic features of both conditions, but UVFD adds another dimension by exploiting the different fluorescence signatures of dermatophyte-infected hair versus follicles in immune-mediated alopecia. The study demonstrated that UVFD produced distinct trichoscopic features for each condition in cases where polarized dermoscopy alone was ambiguous, enabling faster and more accurate differential diagnosis without any invasive procedures.
This matters in practice because getting a culture takes days, and starting the wrong treatment while you wait can cause harm. Trichoscopy, including UVFD where available, gives you actionable information in the room.
The trichoscopic signatures to know: alopecia areata in children shows exclamation mark hairs (hairs that taper toward the scalp end), cadaverized (black dot) hairs from hair breaking at the skin surface, yellow dots from empty follicle infundibula, and perifollicular pigmentation. Tinea capitis shows comma hairs, corkscrew hairs, black dots with a different distribution pattern, and scaling at the follicular openings. The presence of perifollicular scaling and comma hairs is strongly suggestive of fungal infection; exclamation mark hairs and yellow dots favor alopecia areata.
Alopecia Areata in Children: The Immune Mechanism
Alopecia areata is the second most common cause of hair loss in children, and understanding why it develops requires understanding what makes the hair follicle uniquely vulnerable to immune attack in the first place.
The healthy hair follicle is an immunologically privileged site. The proximal region of the follicle suppresses MHC class I expression and limits immune cell infiltration, essentially hiding from immune surveillance during the anagen phase. This privilege is actively maintained through local production of immunosuppressive factors including TGF-β, α-MSH, and ACTH. When that privilege collapses, whether triggered by stress, infection, genetics, or mechanisms still not fully understood, the follicle becomes visible to the immune system.
What follows is an NKG2D+ CD8+ T cell-mediated attack on the follicular epithelium. These cells release interferon-gamma (IFN-γ), which activates follicular dermal sheath cells to produce IL-15. IL-15 further amplifies the CD8+ T cell response, creating a self-sustaining inflammatory loop that drives the follicle out of anagen and into a dystrophic or catagen-like state. The follicle doesn't die in alopecia areata. It's suppressed. That's the distinction that makes it non-scarring, and that's the distinction that makes it potentially treatable — if you can interrupt the loop.
In children, the presentation of alopecia areata is similar to adults: smooth, non-scarring patches, often round or oval, typically on the scalp. The clinical course, however, is more variable. Children are more likely to experience extensive disease, including alopecia totalis (complete scalp hair loss) and alopecia universalis (total body hair loss), than adults presenting with their first episode. The presence of nail involvement, specifically nail pitting, ridging, or trachyonychia, in roughly 25% of affected children, is a useful diagnostic clue and also correlates with more severe and persistent disease. Ophiasis pattern (loss tracking the scalp margins) is associated with poorer prognosis at any age.
Parents often arrive having read that alopecia areata is an autoimmune condition and they want to know why their child's immune system is "attacking" them. The honest answer is that we don't fully know what triggers immune privilege collapse in the follicle for any given individual, and that the research is still active on that question. What we do know is that the follicle itself is intact and capable of recovering — and that the goal of treatment is to dampen the immune response long enough to allow that to happen. That framing is accurate, hopeful without overclaiming, and gives parents something useful to work with.
JAK Inhibitors: The First Real Treatment Shift for Severe Pediatric AA
For most of the history of alopecia areata treatment, the options for children with severe, extensive disease were limited: intralesional or systemic corticosteroids (with significant side effect profiles and poor tolerability in younger children), topical sensitizers like DPCP, or watchful waiting. None of those options had strong evidence in pediatric populations, and none reliably produced sustained regrowth in alopecia totalis or universalis.
JAK inhibitors changed that calculus, first in adults and now in adolescents. The mechanism is direct: JAK1/JAK3 inhibition blocks the cytokine signaling cascade that drives the CD8+ T cell attack on the follicle. Without that signal amplification, the inflammatory loop that suppresses the follicle breaks down, and the follicle can re-enter anagen.
Ritlecitinib, an oral selective JAK3/TEC family kinase inhibitor, became the first JAK inhibitor FDA-approved for patients aged 12 and older when it received approval in June 2023. The adolescent subgroup from the ALLEGRO phase 2b/3 trial enrolled 105 patients between 12 and 17 years of age with at least 50% scalp hair loss. At 24 weeks, 17–28% of adolescents in the ritlecitinib 30 mg and higher dose groups achieved a SALT score ≤20 (meaning 80% or more scalp coverage) compared to 0% in the placebo group. That response rate is meaningful in a population with severe disease that previously had no approved treatment option.
Tofacitinib, a broader JAK1/2/3 inhibitor, has the largest pediatric evidence base even though it doesn't carry formal FDA approval for alopecia areata in children. A 2025 retrospective study by Mahajan and colleagues examined 36 pediatric patients on oral tofacitinib for moderate-to-severe alopecia areata, adding to a growing body of observational and small trial data. A meta-analysis published prior to these studies, examining 10 pediatric studies across 69 patients, reported that 68.5% achieved a good response and 7.7% a partial response to JAK inhibitor therapy overall. Oral administration was significantly more efficacious than topical formulations.
All JAK inhibitors carry the FDA-required black-box warning for serious infections, cardiovascular events, malignancy risk, and thrombosis. These risks are real and must be part of any informed consent discussion. In pediatric patients, the risk-benefit calculation is shaped by disease severity: a child with alopecia universalis who has no other effective options faces meaningful quality-of-life consequences from untreated disease, and that context matters when weighing treatment decisions alongside a physician.
Telogen Effluvium in Children: What's Different
Telogen effluvium occurs in children when a physiological or systemic stressor shifts an abnormal proportion of follicles into the telogen (resting) phase, resulting in diffuse shedding two to four months later. In children, common triggers include high fever, hospitalization, severe illness, rapid weight loss, major surgery, and psychological stress. The COVID-19 pandemic produced an observable increase in pediatric telogen effluvium cases, a fairly direct illustration of how significant systemic stress translates to follicle cycle disruption.
The presentation in children is diffuse shedding rather than patchy loss, and the history almost always reveals a triggering event if you ask specifically for what happened two to four months before shedding began. Trichoscopy shows predominantly telogen hairs with short regrowing vellus-to-terminal hairs at the temples and frontal hairline, without the trichoscopic markers of alopecia areata or tinea capitis.
Acute telogen effluvium in children is self-limiting. Once the triggering stressor is removed or resolved, regrowth typically follows over 6 to 12 months at a rate of approximately 1 cm per month. Topical minoxidil, which has modest evidence in adult telogen effluvium, has not been adequately studied in children, and its use in pediatric patients outside of specialist supervision is not established. The most important clinical intervention is reassurance that the follicle is intact, that regrowth will occur, and that there is a specific and identifiable cause.
What's Still Hard: The Diagnostic Challenges That Persist
The pediatric hair loss diagnostic challenges that the 2025 literature highlights are not simply about having the right tools. They're about having the right index of suspicion in every category simultaneously.
A 2023 study analyzing 3.9 million children with hair loss diagnoses in the United States found that a substantial proportion of tinea capitis cases were managed with inadequate diagnostic testing and subtherapeutic antifungal prescribing. Children received topical antifungals that cannot cure tinea capitis, antibiotics for presentations that were fungal, or no antifungal at all in cases where the diagnosis was uncertain and empirical treatment defaulted to something less specific. The downstream consequences of those diagnostic misses are avoidable scarring and prolonged disease.
The diagnostic framework that consistently produces the best outcomes in pediatric hair loss involves four elements: a careful scalp examination using dermoscopy (and UVFD where available), a fungal culture whenever tinea capitis cannot be confidently excluded, a focused history that specifically asks about timeline and potential triggers, and nail examination in every case of patchy hair loss to identify the marker of systemic immune involvement that points toward alopecia areata. None of those steps require advanced equipment or extensive time. They require attention to the specific ways pediatric presentations differ from adult ones.
Trichologists working with pediatric patients are operating in a space where diagnosis matters acutely. Tinea capitis requires systemic antifungal prescribing, which is physician territory. JAK inhibitor prescribing for alopecia areata requires medical oversight with appropriate screening and monitoring. Your role in pediatric cases is assessment, trichoscopic evaluation, documentation, and referral — not independent management of conditions that require physician-level diagnosis and prescribing. Building referral relationships with pediatric dermatologists is not optional for practitioners who see children regularly. It's a clinical responsibility.
What This Means for Practitioners
Children with hair loss present a different diagnostic problem than adults, and treating them as if they don't is where clinical errors originate. The conditions that dominate pediatric alopecia — tinea capitis, alopecia areata, telogen effluvium — each have distinct mechanisms, trichoscopic signatures, and treatment pathways. The overlap between them is real and requires structured diagnostic thinking to navigate.
The 2024 and 2025 literature has added two significant developments: a structured algorithmic approach to the pediatric workup that formalizes best practices, and FDA approval of ritlecitinib for adolescents aged 12 and older with severe alopecia areata — the first approved treatment for this population in the history of the disease. Neither development changes the fundamental importance of getting the diagnosis right first. A JAK inhibitor prescribed for what is actually tinea capitis is not a treatment. It's a complication.
Know the trichoscopic features. Know when to culture. Know which conditions require physician prescribing to manage, and build the referral relationships that let you serve these patients well. The science supports doing this well. The patients need you to.
The Bottom Line
Pediatric hair loss is not adult alopecia at a smaller scale. The most common causes in children — tinea capitis (fungal, requires systemic antifungal), alopecia areata (immune-mediated, now with FDA-approved JAK inhibitor therapy for adolescents ≥12), and telogen effluvium (self-limiting after stressor resolves) — each require distinct diagnostic and clinical approaches. Trichoscopy, including ultraviolet-induced fluorescence dermoscopy, enables differentiation of tinea capitis from alopecia areata at the chair without waiting for culture results. A 2025 algorithmic framework from the Australasian Journal of Dermatology formalizes the workup logic for pediatric hypotrichosis. The diagnostic mistakes that produce preventable outcomes — missed tinea, kerion managed as bacterial abscess, tinea treated as alopecia areata — are avoidable with the right index of suspicion and the right tools.