OFFICIAL ABP TOPIC:

Understand the differential diagnosis, evaluation, and management of hair loss

BACKGROUND

Hair loss, also known as alopecia, is a common chief complaint in pediatrics. While often benign and self-limited, it may cause significant emotional distress for children and families. Alopecia can also be a symptom of an underlying systemic illness or genetic condition that is important for the pediatrician to identify.

DIFFERENTIAL DIAGNOSIS OF HAIR LOSS

The most common causes of hair loss in children include:

Tinea Capitis

• Dermatophyte infection of the scalp
• Patchy hair loss with erythema, scaling, and broken hairs/black dots
• Cervical lymphadenopathy often present

Alopecia Areata

• Autoimmune-mediated, non-scarring hair loss
• Well-circumscribed patches of complete hair loss, usually without erythema or scale

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• Exclamation point hairs at edges of patches: short, broken hairs that are narrower closer to the scalp
• May progress to total scalp (alopecia totalis) or full body (alopecia universalis) involvement

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• May progress to total scalp (alopecia totalis) or full body (alopecia universalis) involvement
• Associated with other autoimmune conditions like thyroid disease and vitiligo

Telogen Effluvium

• Temporary shedding of hair 2-4 months after an inciting event like illness, surgery, or new medication
• Presents with diffuse thinning but no discrete patches
• Positive hair pull test (>10% of hairs are easily pulled out when 20-60 hairs are grasped and gently pulled)
• Self-resolving once trigger is removed

Traction Alopecia

• Hair loss due to persistent or repetitive tension on hair follicles
• Common in patients who wear tight hairstyles like braids or ponytails
• Presents with patchy loss or thinning at sites of traction, especially the frontotemporal scalp

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• Scarring and permanent loss can occur if traction continues

Trichotillomania

• Impulse control disorder causing patients to compulsively pull out their own hair
• Irregular patches of broken hairs of varying lengths

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• Most common in adolescents and may be associated with other psychiatric conditions

Congenital Causes

• Aplasia Cutis Congenita: Focal absence of skin, subcutaneous tissue, and hair, usually on the scalp vertex at birth. Can be isolated or associated with other congenital anomalies.
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• Congenital Triangular Alopecia: Triangular or lancet-shaped patch of hair loss, often unilateral and temporal. Non-progressive and present since birth.
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• Congenital Atrichia/Hypotrichosis: Rare disorders of total absence or marked reduction in hair density from birth/infancy. Linked to mutations in hair development genes.
• Hair Shaft Abnormalities: Structural defects in the hair fiber (e.g., monilethrix, trichorrhexis nodosa) causing sparse, fragile hair. Can be acquired from damage or congenital.

Other Causes

• Discoid Lupus Erythematosus: Scarring alopecia with erythematous, scaly patches. In children, there is an increased risk of progression to systemic lupus erythematosus (SLE) compared to adults.
• Heavy Metal Poisoning: Diffuse thinning or alopecia reported with chronic exposure to thallium, mercury, and other metals. Exposure history is key.

EVALUATION OF HAIR LOSS

Diagnosis of pediatric alopecia starts with a thorough history and physical exam:

• Age of onset (congenital or acquired)
• Associated symptoms like pruritus or tenderness
• Ability to easily extract hairs
• Progression of loss – transient or chronic
• History of hair care practices
• Medication and family history
• Appearance and distribution of hair loss on scalp and body (focal or diffuse pattern)
• Presence of scarring, erythema, scaling, or skin lesions

Fungal studies (KOH prep, culture) should be obtained if tinea capitis is suspected.

If alopecia areata or an underlying systemic illness is suspected, consider lab tests:

• For possible alopecia areata, check thyroid function tests (TSH, free T4) and vitamin D levels.
• If signs of systemic disease are present (e.g., fatigue, pallor, failure to thrive), obtain CBC, iron studies, and zinc levels to screen for anemia and nutritional deficiencies.

Trichoscopy (dermoscopy of the scalp) can help differentiate between scarring and nonscarring alopecia and reveal diagnostic clues like exclamation point hairs.

• Scarring alopecia: Permanent destruction of follicles. Loss of follicular ostia and shiny, indurated scalp on exam.
• Non-scarring alopecia: Follicles preserved, potential for regrowth. Ostia visible on exam.

Refer to dermatology if the diagnosis is unclear. Scalp biopsy is rarely needed but can distinguish between conditions.

MANAGEMENT OF HAIR LOSS

Tinea Capitis

• Oral antifungals (griseofulvin, terbinafine) for 4-8 weeks
• Selenium sulfide or ketoconazole shampoos to limit spread
• Screen and treat household contacts

Alopecia Areata

• Topical steroids are first-line, especially for limited disease
• Intralesional steroid injections for older children with discrete patches
• Topical minoxidil may help promote regrowth
• Topical immunotherapy for extensive, refractory cases

Telogen Effluvium

• Resolve underlying trigger – no specific treatment needed
• Reassurance – regrowth occurs in 3-6 months

Traction Alopecia

• Discontinue tight hairstyles, avoid heat and chemicals
• Anti-inflammatory agents (steroids, antibiotics) if folliculitis is present
• Scarring and permanent loss may occur if traction persists

Trichotillomania

• Cognitive behavioral therapy is the mainstay of treatment
• N-acetylcysteine and olanzapine may help in some cases
• Rule out comorbid anxiety, depression, or OCD

Congenital Alopecias

• Mainly supportive – no effective treatments available
• Gentle hair care and avoidance of trauma
• Consider genetic testing for associated syndromes

Preventive Guidance

• Traction Alopecia: Educate patients/parents to avoid tight hairstyles, excessive heat, or harsh chemicals. Recommend low-tension styles and gentle hair care.
• Trichotillomania: Teach habit reversal techniques (e.g., competing responses when the urge to pull strikes). Advise parents to provide positive reinforcement for resisting pulling.

Psychosocial support is a key aspect of managing pediatric alopecia of any cause. Counseling patients and families about the likely course and setting realistic expectations is important. Dermatology referral may be helpful for refractory or diagnostically challenging cases.

REFERENCES

https://publications.aap.org/pediatricsinreview/article/41/11/570/35358/Hair-Loss