• Sebaceous nevus
• Epidermal nevus
• Hair follicle hamartomas
• Aplasia cutis congenita
• Conradi disease
• Incontinentia pigmenti
• Triangular alopecia of the frontal scalp
• Goltz syndrome (poikiloderma with focal dermal hypoplasia, syndactyly, localized areas of scalp and pubic alopecia, dystrophic nails, dental abnormalities)
• Hair shaft defects such as trichorrhexis nodosa (broomstick fractures), pili torti (twisted hair), monilethrix (beaded hair), trichorrhexis invaginata (bamboo hair)
• Ectodermal dysplasias

• Tinea capitis, including untreated kerion
• Varicella

• Chemotherapeutic agents (anagen effluvium)
• Thallium poisoning
• Heparin
• Coumadin
• Antimetabolites
• Hypervitaminosis A
• Radiation injury (anagen effluvium)
• Chemical or thermal burns

• Traction alopecia
• Trichotillomania
• Friction
• Scarring from pyoderma

• Congenital or acquired hypothyroidism
• Hypopituitarism
• Hypoparathyroidism
• Diabetes mellitus
• Progeria
• Marasmus
• Zinc deficiency (acrodermatitis)

• Alopecia areata: thought to be due to dysregulation of the immune system, with all patients having hair antigen autoantibodies
• Lichen planus
• Systemic lupus erythematosis (SLE)
• Darier disease (keratosis follicularis—greasy, crusted papules on scalp, face, neck, trunk, and extremities)
• Porokeratosis of Mibelli (hyperkeratotic plaques with raised border and central atrophy)

• Telogen effluvium

• Recognize that most cases of acquired, circumscribed alopecia are due to three major causes: tinea capitis, alopecia areata, or trauma.
• Always culture acquired circumscribed alopecia for dermatophytes, regardless of clinical presentation, because tinea capitis is by far the most common etiology.

Question: Is the hair loss congenital or acquired? Circumscribed or diffuse?
Significance: Most cases of acquired circumscribed alopecia will be tinea capitis, alopecia areata, or traumatic alopecia.

Question: Does the child have any chronic medical conditions?
Significance: Increased incidence of alopecia areata in patients with Down syndrome, thyroiditis, and vitiligo. SLE and endocrinopathies.

Question: Is the child taking any medications?
Significance: Anticoagulants, antimetabolites, and high-dose vitamin A may result in alopecia.

Question: Has the child been exposed to anyone with ringworm or any animals such as dogs, cats, or cattle?
Significance: Tinea capitis may be spread from person-to-person and animal-to-person, depending on the type of fungus involved. More than 90% of cases in North America are caused by Trichophyton tonsurans, affecting largely prepubertal children. Other infectious agents are Microsporum canis, which also affects cats and dogs, and Trichophyton errucosum, which affects cattle and humans. With infections caused by M. canis, there is no human-to-human transmission, as humans are terminal hosts.

Question: Does the child twist or pull at her hair?
Significance: Trichotillomania is a condition where the person pulls out her own hair. It is more common in girls, with a mean age of onset of 12 years. It is fairly common, with 1 in every 100 children engaging in this activity at some time or another. It may be associated with obsessive-compulsive disorder, an underlying psychiatric disturbance, or a response to a recent traumatic event.

Question: Is there a familial history of alopecia areata?
Significance: There is a familial history of alopecia areata in 10% to 20% of cases.

Question: Has there been a stressful event in the past several months?
Significance: Telogen effluvium is when hairs rapidly convert from growing, or anagen state, to the resting, or telogen, state. It is often precipitated by acute stressful events such as major accidents, fevers, fractures, psychiatric events, crash diets, or major surgery; after 2 to 4 months, the hairs in the telogen state are shed over a period of 3 to 4 months. Trichotillomania sometimes occurs in response to a stressful event.

Question: Does the child have an unusual diet?
Significance: Hypervitaminosis A and zinc deficiency can result in alopecia.

Question: What are the hair care practices of the child (frequency of shampooing, brushing, curling, braiding, or ponytails)?
Significance: Traction alopecia may occur with tight braids or corn rows, tightly pulled pony tails, excessive brushing, tight hair curlers, or frequent shampooing.

Finding: Is there a circumscribed bald spot that has been present since birth?
Significance: Consider aplasia cutis congenita, sebaceous nevus, or epidermal nevus in the differential diagnosis.

Finding: Are there abnormalities of nails, hair, and teeth?
Significance: Ectodermal dysplasia: hidrotic ectodermal dysplasia consists of hyperkeratosis of the palms and soles, dystrophic nails, and diffuse scalp and body alopecia (more prominent after puberty). Hypohidrotic ectodermal dysplasia includes abnormal dentition and defective or absent sweating.

Finding: In the area of alopecia, are small dark hairs visible, giving the appearance of “black dot” alopecia?
Significance: In tinea capitis, hairs break off at the follicular orifice. This occurs during the non-inflammatory stage of infection.

Finding: Are there scaly, bald patches in scalp?
Significance: These may be seen in tinea capitis, and with atopic dermatitis or seborrhea. The bald patches are traumatic alopecia due to rubbing/scratching.

Finding: Are pustules seen in the scalp?
Significance: These may be seen with pyogenic infections, chronic follicular trauma (e.g., traction), and tinea capitis (inflammatory stage).

Finding: Are pits visible in the nails?
Significance: Nail pits may precede the hair loss seen with alopecia areata.

Finding: Are hairs easily plucked and have tapered proximal shafts (“exclamation point” hairs)?
Significance: This phenomenon may be seen in alopecia areata.

Finding: Are there patches of non-scarring alopecia with irregular, ill-defined borders?
Significance: These are suggestive of trichotillomania or other forms of trauma.

Finding: Are there broken hairs of variable lengths?
Significance: This occurs in trichotillomania.

Finding: Are there perifollicular petechiae or excoriations?
Significance: These may occur in trichotillomania.

Test: Fungal culture
Significance: This is the gold standard for detecting dermatophytes.

Test: Microscopic examination of hair scrapings dissolved in KOH.
Significance: This is an alternative test for dermatophytes infections. This test requires considerable skill and experience.

Test: Microscopic examination of lost hairs.
Significance: In telogen effluvium, the root is non-pigmented and bulb shaped.

Test: Wood light examination
Significance: This is useful only with Microsporum canis and M. audouinii infections, with the hairs fluorescing bright yellow-green, and Trichophyton schoenleinii, fluorescing pale green. Trichophyton tonsurans does not cause fluorescence.

Test: Thyroid function tests
Significance: Should be performed when there is diffuse alopecia to rule out hypothyroidism.

Q: Will the child’s hair regrow after tinea capitis?
A: Yes. Hair regrowth may begin in 2 weeks, but full regrowth takes 3 to 6 months. Uncommonly, kerions may result in scarring and permanent hair loss.

Q: Will the child with alopecia areata regrow hair?
A: Yes. In 95% of initial cases, hair will regrow completely within 1 year from the onset of symptoms.

Q: What routine blood work-up should be done in evaluating alopecia?
A: None. With diffuse alopecia, history and physical examination should guide the ordering of additional laboratory studies.

Q: What is the first-line therapy for tinea capitis infections?
A: Griseofulvin (20 mg/kg/day) for a minimum of 8 weeks. Addition of selenium sulfide 2.5% shampoo twice weekly may hasten eradication of dermatophyte and decrease spread to others. Topical antifungals have poor penetration into the hair shaft and are, therefore, ineffective in treating tinea capitis.

Q: Is therapy of kerions different than non-inflammatory tinea capitis?
A: No. Studies have shown that the addition of prednisone and/or antibiotics when treating kerions does not hasten resolution.

• All but acquired circumscribed alopecia
• Recurrent alopecia areata

• Plucking hairs for culture may cause a false-negative result because hairs long enough to be grasped are uninfected; always use scalp scrapings obtained with a soft sterile brush or curet.
• Up to 5% of children living in crowded cities carry Trichophyton tonsurans.
• In performing Wood light examinations, false-negatives may occur if the room is not dark enough, and false-positives may occur if one confuses the bluish or purple fluorescence of hair scale, lint, or petrolatum ointments with the greenish fluorescence of infected hairs.

Levy ML. Disorders of the hair and scalp in children. Pediatr Clin North Am 1991;38(4):905–919.

Suarez S, Fallon Friedlander S. Antifungal therapy in children: an update. Pediatr Ann 1998;27(3):177–184.

Vasiloudes P, Morelli JG, Weston WL. Bald spots: remember the “big three.” Contemp Pediatr 1997;14(10):76–91.