What Is Alopecia Areata?
Alopecia areata is an autoimmune disease that causes non-scarring hair loss, typically in well-defined circular áreas on the scalp. The immune system attacks the hair follicles, interrupting the hair growth cycle without permanently destroying the follicle.
The disease can affect any hair-bearing área of the body, including the beard, eyebrows, eyelashes, and body hair. Its severity ranges from small isolated patches (the most common form) to total loss of scalp hair (alopecia totalis) or of all body hair (alopecia universalis).
Alopecia areata affects roughly 2% of the population over a lifetime. It can arise at any age, but more than half of cases begin before age 30. The unpredictable clinical course — with episodes of loss and regrowth — is one of the most challenging features of the disease.
Autoimmune Disease
T lymphocytes attack the hair follicle, causing localized hair loss without permanently destroying the follicle.
Patchy Pattern
Circular or oval áreas of hair loss with smooth skin, no scarring, and "exclamation-mark" hairs at the borders.
Unpredictable Course
Episodes of loss and spontaneous regrowth. In up to 50% of cases, hair regrows spontaneously within 1 year.
Pathophysiology
The healthy hair follicle has an immune privilege — a microenvironment that protects it from immune system attack. In alopecia areata, this privilege is disrupted: cytotoxic CD8+ and helper CD4+ T lymphocytes infiltrate the follicular bulb, creating a characteristic peribulbar inflammatory infiltrate described as a "swarm of bees".
The central mechanism involves the interferon-gamma (IFN-γ) and Janus kinase (JAK) pathway. CD8+ T lymphocytes release IFN-γ, which induces expression of MHC class I and II in the follicle (normally suppressed), perpetuating the autoimmune attack. JAK-STAT signaling is critical in this process, which explains the efficacy of JAK inhibitors.
Genetic factors contribute significantly: 42-55% concordance in identical twins, association with HLA genes (especially HLA-DQB1), and genes linked to other autoimmune diseases. Environmental factors such as psychological stress, infections, and skin-microbiota shifts may act as triggers in genetically susceptible individuals.
Symptoms
The principal symptom is hair loss in well-defined áreas, generally without significant pain or itching. Loss can occur abruptly, with the patient noticing bald patches when combing or after being observed by others. Occasionally, a mild burning or tingling sensation may precede the loss.
Clinical Manifestations of Alopecia Areata
- 01
Circular/oval alopecia patches
Well-defined hair-loss áreas, with smooth skin in normal or slightly pink tones. The most common pattern is one or a few scalp patches.
- 02
"Exclamation-mark" hairs
Short hairs (3-4 mm) that taper at the base, found along active-patch borders. They are a pathognomonic sign of alopecia areata.
- 03
Nail changes
Pinpoint depressions (pitting), longitudinal striations, roughness, and nail fragility. Present in 10-40% of cases.
- 04
Beard alopecia
Hair-loss patches in the beard. May be the only manifestation or coexist with scalp patches.
- 05
Regrowth with white hairs
When hair regrows, it may initially be white or depigmented, regaining its normal color over weeks to months.
- 06
Significant psychological impact
Anxiety, depression, reduced self-esteem, and social isolation are common. The psychological impact is often disproportionate to the affected área.
CLINICAL FORMS OF ALOPECIA AREATA
| FORM | DESCRIPTION | FREQUENCY |
|---|---|---|
| Patchy alopecia areata | One or more circular patches on the scalp | 75-80% of cases |
| Ophiasis alopecia areata | Band of alopecia along the occipital and temporal margin | 5% of cases; worse prognosis |
| Alopecia totalis | Total loss of scalp hair | 5-10% of cases |
| Alopecia universalis | Loss of all body hair | ~1% of cases |
| Diffuse alopecia areata | Diffuse thinning without defined patches (difficult diagnosis) | Uncommon |
Diagnosis
The diagnosis is primarily clinical, based on the typical pattern of patchy hair loss with normal-appearing skin. Dermoscopy (trichoscopy) is the main complementary tool, identifying characteristic findings such as yellow dots, black dots, and "exclamation-mark" hairs.
Scalp biopsy is rarely needed but can be useful in atypical presentations. It shows the characteristic peribulbar lymphocytic infiltrate. Laboratory workup should include screening for associated autoimmune diseases, especially thyroid disorders.
🏥Diagnostic Evaluation
Fonte: AAD and BAD Guidelines
Typical Clinical Findings
- 1.Circular/oval alopecia patches with smooth skin
- 2."Exclamation-mark" hairs at active borders
- 3.Positive pull test at patch margins
- 4.Skin without atrophy, fibrosis, or scarring
- 5.Possible nail changes (pitting)
Dermoscopy (Trichoscopy)
- 1.Yellow dots: follicular ostia filled with keratin/sebum
- 2.Black dots: hair shafts fractured at skin level
- 3."Exclamation-mark" hairs: proximal tapering
- 4.Short vellus hairs: sign of regrowth
Laboratory Tests
- 1.TSH and antithyroid antibodies (TPO)
- 2.Complete blood count
- 3.Vitamin D, ferritin, zinc
- 4.ANA (if systemic autoimmune disease is suspected)
Differential Diagnosis
Alopecia areata must be distinguished from other causes of hair loss. The pattern of circular patches with intact skin, along with trichoscopy, are essential tools for clinical distinction.
DIFFERENTIAL DIAGNOSIS
Differential Diagnosis
Androgenetic Alopecia
- M-shaped pattern in men
- Gradual loss
- No fully bald circular áreas
Tinea Capitis
- Children
- Scaling and inflammation
- Fungal
- Tinea in a child = treat urgently
Diagnostic Tests
- KOH
- Fungal culture
Discoid Lupus Erythematosus
- Atrophic scarring
- Erythema
- Positive ANA
Diagnostic Tests
- ANA
- Biopsy
Traction Alopecia
- Related to tight hairstyles
- Frontal margin
- No autoimmunity
Telogen Effluvium
- Diffuse loss after physical/emotional stress
- No patches
- Spontaneous recovery
Tinea Capitis and Discoid Lupus: Diagnoses That Cannot Be Missed
Tinea capitis occurs predominantly in children and presents, alongside hair loss, with inflammatory scaling, erythema, and occipital adenopathy. Wood's lamp examination (green fluorescence with M. canis) and KOH of scrapings are rapid and confirmatory. Early treatment with oral griseofulvin or terbinafine prevents progression and intra-family transmission.
Discoid lupus erythematosus causes irreversible scarring alopecia if not treated early. Atrophic scars with peripheral hyperpigmentation and central hypopigmentation, along with erythema and follicular plugs, distinguish it from alopecia areata. Biopsy confirms the diagnosis, and treatment with antimalarials and corticosteroids should be started promptly.
Androgenetic vs. Areata Alopecia: Pattern and Distribution
Androgenetic alopecia (common baldness) follows a predictable pattern — Hamilton-Norwood in men (frontal hairline recession and vertex balding) and Ludwig in women (diffuse thinning at the top) — without circumscribed bald patches. The gradual transition contrasts with the often abrupt onset of alopecia areata.
On trichoscopy, androgenetic alopecia shows progressive follicular miniaturization with variable hair diameter, without the yellow dots and black dots characteristic of alopecia areata. The medical acupuncturist evaluates both conditions in an integrated way, recognizing that they may coexist in the same patient.
Telogen Effluvium: Diffuse Loss After Stress
Telogen effluvium manifests as intense diffuse hair loss, generally 2 to 4 months after a triggering event (surgery, childbirth, severe illness, intense emotional stress). It does not form well-defined patches and usually recovers spontaneously in 6 to 12 months. The pull test is diffusely positive, unlike alopecia areata, which is positive only along active-patch borders.
Investigating nutritional deficiencies (ferritin, zinc, vitamin D) and thyroid disorders is essential in telogen effluvium. Acupuncture may have a complementary role in stress management as part of treatment, while the underlying cause is identified and corrected.
Treatment
Alopecia areata treatment depends on disease extent, the patient's age, and the impact on quality of life. The arrival of JAK inhibitors (baricitinib, FDA-approved 2022) represented a significant advance for extensive forms of the disease.
Limited Disease (<50% of the scalp)
First lineHigh-potency topical corticosteroids (clobetasol) or intralesional injections (triamcinolone acetonide 5-10 mg/mL every 4-6 weeks). Topical 5% minoxidil as adjuvant. Response in 4-8 weeks after intralesional corticosteroid.
Extensive Disease (>50% of the scalp)
Systemic treatmentJAK inhibitors: baricitinib 2-4 mg/day (JAK1/JAK2). Response in 3-6 months. Ruxolitinib and tofacitinib as alternatives. Pulsed oral corticosteroids for rapid rescue.
Topical Immunotherapy
Option for extensive diseaseDiphencyprone (DPCP): a sensitizer that induces controlled contact dermatitis, redirecting the immune response. Applied weekly at increasing concentrations. Response in 3-6 months in 40-60% of patients.
Psychological Support
OngoingPsychotherapy (CBT) to manage emotional impact. Support groups. Hair prostheses and cosmetic camouflage. Anxiety and depression assessment.
Acupuncture as Treatment
Acupuncture is used as a complementary therapy in alopecia areata, focused on two main mechanisms: immunomodulation and improvement of local microcirculation in the scalp. Experimental studies show that acupuncture can modulate the Th1/Th2 immune response, reduce pro-inflammatory cytokines, and increase local blood perfusion.
Specific techniques include local acupuncture (needling around and within alopecia patches), which stimulates microcirculation and may promote growth factors. Electroacupuncture can modulate the neuroendocrine stress response, a recognized triggering factor for alopecia areata.
In clinical practice, acupuncture can be combined with conventional dermatologic treatment. It is considered especially useful when stress is identified as a trigger, and for patients who seek approaches that complement immunologic treatment.
Prognosis
Alopecia areata has a variable prognosis. In limited forms (a few small patches), spontaneous regrowth occurs in up to 50% of patients within 1 year. With appropriate treatment, response rates are even higher.
Factors associated with worse prognosis include: onset before puberty, prolonged duration, extension above 50% of the scalp, ophiasis pattern, atopy, and extensive nail changes. Alopecia totalis/universalis has the lowest rates of sustained complete regrowth, although JAK inhibitors have significantly improved these prospects.
Myths and Facts
Myth vs. Fact
Alopecia areata is caused by emotional stress.
Stress can act as a trigger in genetically susceptible individuals, but it is not the cause of the disease. Alopecia areata is fundamentally an autoimmune disease with a strong genetic component.
Myth vs. Fact
The follicles are dead and the hair will never grow back.
In alopecia areata, follicles are attacked but not destroyed — it is a non-scarring alopecia. The follicles retain the capacity to generate new hairs, which explains why regrowth remains possible even after years.
Myth vs. Fact
Hair products or special shampoos can cure alopecia areata.
No cosmetic product or shampoo treats alopecia areata, which requires immunomodulatory medical treatment. Hair products may help camouflage it, but they do not influence disease course.
When to Seek Care
Frequently Asked Questions
Frequently Asked Questions
Alopecia areata has no definitive cure, but spontaneous remission is frequent. In limited forms, up to 50% of patients regrow hair spontaneously within 1 year. Modern treatments — especially JAK inhibitors (baricitinib) — allow significant hair recovery even in extensive forms such as alopecia totalis.
Yes. Because hair follicles are attacked but not destroyed, hair growth can resume at any time. Hair may regrow white at first, regaining its natural color over weeks to months. Even after years of alopecia totalis, regrowth can occur — especially with newer treatments.
Stress is a recognized trigger in genetically susceptible individuals, but it is not the cause of the disease. Alopecia areata is fundamentally autoimmune. Reducing stress can help cut recurrence frequency, but it does not treat the underlying cause. Stress management — including techniques such as acupuncture — is a valid complementary component of treatment.
No. Alopecia areata is an autoimmune disease, with no infectious or contagious component. It is not transmitted by contact, shared objects, or any other route. Family members of patients carry a slightly higher risk because they share susceptibility genes, not through contagion.
Acupuncture can be used as a complementary therapy, focused on immunomodulation and improving local scalp microcirculation. Clinical studies show additional benefit when combined with conventional treatment, especially in patients with a relevant emotional component. The medical acupuncturist evaluates each case individually to recommend the most appropriate protocol.
Alopecia areata is associated with a higher prevalence of other autoimmune diseases — especially autoimmune thyroid disorders (Hashimoto's thyroiditis), vitiligo, type 1 diabetes, and inflammatory bowel diseases. Thyroid screening with TSH and anti-TPO antibodies is recommended in all patients.
JAK inhibitors (baricitinib, ruxolitinib, tofacitinib) block the JAK-STAT pathway, interrupting IFN-γ signaling that perpetuates the immune attack on the follicle. They are indicated for extensive forms (more than 50% of the scalp) or refractory cases. The main limitation is recurrence after drug discontinuation, which makes long-term treatment necessary in many cases.
Yes. Pediatric treatment is adapted to age: high-potency topical corticosteroids and intralesional injections are first-line options. Topical minoxidil is used as an adjuvant. JAK inhibitors may be considered in adolescents with extensive refractory disease. Psychological support is especially important in this age group, given the impact on self-esteem.
Yes, in 10 to 40% of cases. Nail changes include pitting (pinpoint depressions), longitudinal striations, roughness (trachyonychia), and leukonychia. Extensive nail changes are considered a worse prognostic factor for hair. Nails may improve with systemic alopecia treatment.
Duration varies with disease extent and treatment response. Limited forms treated with intralesional corticosteroid can achieve regrowth in 4 to 12 weeks. Extensive forms on JAK inhibitors require continuous treatment — often indefinite — because recurrence after discontinuation is frequent. Regular dermatologist follow-up is essential to adjust treatment.
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