Overview
Definition:
Tinea capitis is a superficial fungal infection of the scalp, hair follicles, and surrounding skin caused by dermatophytes
Alopecia areata is a non-scarring, autoimmune disorder characterized by patchy hair loss on the scalp and/or other hair-bearing areas.
Epidemiology:
Tinea capitis is common in school-aged children, with peak incidence between ages 3 and 7 years
it is less common in adults
It is more prevalent in socioeconomically disadvantaged populations and can spread through direct contact, fomites, or animal reservoirs
Alopecia areata affects approximately 0.1% to 0.2% of the general population, with onset often in childhood or adolescence
There is a bimodal age distribution with peaks in early childhood and adulthood
Family history of autoimmune diseases is common.
Clinical Significance:
Both conditions can cause significant psychosocial distress in children due to visible hair loss
Accurate differentiation is crucial as their etiologies, diagnostic approaches, and management strategies are entirely different
Misdiagnosis can lead to ineffective or harmful treatments, delayed appropriate therapy, and prolonged distress for the child and family.
Clinical Presentation
Tinea Capitis Symptoms:
Itchy scalp
Scaly patches or plaques on the scalp
Broken hairs at the scalp surface (black dots)
Patches of hair loss
May present with pustules or a boggy, inflamed mass (kerion).
Alopecia Areata Symptoms:
Sudden onset of one or more smooth, round or oval patches of hair loss on the scalp
Patches may enlarge over time
No pain or significant itching typically
Nail changes (pitting, ridging) may be present in some cases.
Tinea Capitis Signs:
Erythematous, scaly patches or plaques on the scalp
Hair breakage at the follicular opening (black dots) or shafts
Diffuse scaling resembling dandruff
A boggy, inflamed, tender mass (kerion) with pustules and discharge may indicate a severe inflammatory response
Lymphadenopathy may be present.
Alopecia Areata Signs:
Well-demarcated, smooth, non-scarring patches of alopecia
Exclamation mark hairs (short, broken hairs tapering towards the scalp surface) at the periphery of lesions
Ophiasis pattern (band-like hair loss along the temporal and occipital scalp)
Nail pitting, onycholysis, or transverse ridging.
Diagnostic Criteria:
No formal diagnostic criteria exist for either condition, diagnosis relies on clinical presentation and investigations
Wood's lamp examination can sometimes reveal fluorescence in certain dermatophyte species (e.g., Microsporum audouinii), but is not always reliable
Definitive diagnosis for tinea capitis is made by microscopy and fungal culture
For alopecia areata, diagnosis is primarily clinical, supported by characteristic findings on scalp examination and trichoscopy.
Diagnostic Approach
History Taking:
Ask about exposure to pets (especially cats and dogs)
Inquire about recent contact with individuals with similar scalp lesions or hair loss
Note any history of scaling, itching, or pustules
Explore family history of alopecia or autoimmune diseases
Ask about previous treatments for scalp conditions.
Physical Examination:
Systematically examine the entire scalp for distribution, type of lesions (scaly patches, pustules, broken hairs, smooth bald areas)
Note the presence of inflammation, lymphadenopathy
Examine nails for changes suggestive of alopecia areata
Assess for other hair-bearing areas (eyebrows, eyelashes, beard).
Investigations:
For suspected Tinea Capitis: Direct microscopy of plucked hairs and skin scrapings with 10-20% potassium hydroxide (KOH) to identify fungal hyphae
Fungal culture on Sabouraud agar with antibiotics and cycloheximide for species identification and sensitivity testing
For suspected Alopecia Areata: Usually no investigations are needed for diagnosis
Trichoscopy may show characteristic findings (black dots, yellow dots, exclamation mark hairs, tapered hairs)
Skin biopsy is rarely indicated but can show a perifollicular lymphocytic infiltrate.
Differential Diagnosis:
Tinea Capitis: Seborrheic dermatitis, psoriasis, bacterial folliculitis, atopic dermatitis, lichen simplex chronicus, discoid lupus erythematosus
Alopecia Areata: Tinea capitis, telogen effluvium, anagen effluvium, traction alopecia, trichotillomania, scarring alopecias (e.g., lichen planopilaris, frontal fibrosing alopecia).
Management
Tinea Capitis Treatment:
Systemic antifungal therapy is essential for tinea capitis due to involvement of the hair follicle
First-line agents: Griseofulvin (20-25 mg/kg/day divided BID, usual duration 6-8 weeks) or Terbinafine (5-8 mg/kg/day QD, usual duration 4-6 weeks)
Alternative agents: Itraconazole, Fluconazole (often less effective for T
tonsurans)
Topical antifungals alone are not sufficient but can be used as adjuncts or for prophylaxis
Kerions may require oral corticosteroids to reduce inflammation and prevent scarring.
Alopecia Areata Treatment:
Management depends on the extent of hair loss
Mild patches: Intralesional corticosteroid injections (e.g., triamcinolone acetonide 3-5 mg/mL diluted with saline, monthly injections)
Topical corticosteroids (potent or very potent)
Topical immunotherapy (e.g., diphencyprone, squaric acid dibutylester) for more extensive disease
Severe or widespread alopecia: Systemic corticosteroids (short courses), topical minoxidil (limited efficacy), or JAK inhibitors (emerging therapies).
Supportive Care Tinea:
Antifungal shampoos (e.g., selenium sulfide, ketoconazole) can reduce spore shedding and prevent transmission
Educate family on hygiene and avoiding sharing personal items
Monitor for side effects of systemic antifungals (e.g., GI upset, hepatotoxicity with griseofulvin
liver function tests may be needed).
Supportive Care Alopecia:
Counseling for the child and family regarding the autoimmune nature and potential for spontaneous regrowth
Wigs or scalp coverings can be considered for cosmetic reasons
Patient support groups can be beneficial.
Complications
Tinea Capitis Complications:
Permanent scarring alopecia (especially with inflammatory kerion or delayed treatment)
Spread of infection to other body sites or individuals
Development of secondary bacterial infections in lesions
Onychomycosis and tinea corporis can co-exist.
Alopecia Areata Complications:
Emotional distress, depression, and anxiety
Social withdrawal
Permanent hair loss in some cases (especially if extensive or long-standing)
Associated autoimmune disorders (e.g., thyroid disease, vitiligo, type 1 diabetes).
Prevention Strategies:
Tinea Capitis: Early diagnosis and prompt treatment
Public health education on hygiene and avoiding sharing hats, combs, towels
Screening of contacts and household pets
Alopecia Areata: Early intervention may improve prognosis
Managing psychological impact
Regular follow-up to monitor disease activity and potential co-morbidities.
Prognosis
Tinea Capitis Prognosis:
Generally good with appropriate systemic antifungal therapy
Most cases resolve within 6-8 weeks of treatment
Recurrence is possible, especially with continued exposure
Inflammatory kerions have a higher risk of scarring.
Alopecia Areata Prognosis:
Variable
Spontaneous remission occurs in up to 80% of patients with limited disease within one year
However, recurrence is common
Extensive disease and early onset (<10 years) are associated with a poorer prognosis for complete regrowth
Nail involvement is also a poor prognostic indicator.
Follow Up:
Tinea Capitis: Follow-up to ensure completion of treatment and monitor for recurrence
Repeat KOH/culture if symptoms persist or recur
Alopecia Areata: Regular follow-up (e.g., every 3-6 months) to assess hair regrowth, monitor for new lesions, and manage psychosocial impact
Consider screening for associated autoimmune conditions if indicated.
Key Points
Exam Focus:
Distinguish tinea capitis (fungal infection, requires systemic antifungals) from alopecia areata (autoimmune, non-scarring, requires different management)
Remember Griseofulvin and Terbinafine as first-line for tinea capitis
Recognize 'black dot' sign for tinea capitis and 'exclamation mark hairs' for alopecia areata
Kerion is a severe inflammatory presentation of tinea capitis.
Clinical Pearls:
Always consider tinea capitis in a child with scalp scaling and hair loss, especially if there are pustules or inflammation
A high index of suspicion is needed for tinea capitis, as clinical presentation can be subtle
For alopecia areata, look for nail changes as a clue
Be patient with alopecia areata treatment
regrowth can take time.
Common Mistakes:
Treating tinea capitis with topical antifungals alone, which is ineffective
Misdiagnosing alopecia areata as a fungal infection and using inappropriate antifungals
Delaying systemic therapy for tinea capitis, increasing the risk of kerion formation and permanent hair loss
Over-treating mild alopecia areata with systemic agents.