Hair Loss
Hair loss (alopecia) from the scalp is commonin children. May be congenital or acquired, localized or diffuse.
Principal Causes of Hair Loss
- Congenitalhair loss
- Localized
- Nevussebaceous of Jadassohn
- Aplasia cutis congenita
- Congenital triangular alopecia
- Diffuse
- Ectodermal dysplasias
- Hair shaft defects
- Loose anagen hair syndrome
- Congenital hypothyroidism
- Acquired hair loss
- Localized
- Tractionalopecia
- Trichotillomania
- Tinea capitis
- Injury
- Alopecia areata
- Other
- Diffuse
- Telogen effluvium
- Anagen effluvium
- Androgenetic alopecia
Clinical Features and Diagnosis
Congenital Hair Loss
Localized
Nevus Sebaceous of Jadassohn
Appearson scalp as smooth, slightly raised, linear or oval, yellow or orange,waxy plaque, which is usually solitary.Because of possibility of developingsecondary tumors during puberty, excision is recommended beforepuberty. Aplasia Cutis Congenita
≥1 ovaldefects, 1–2 cm in diameter, appear as ulcerlike lesions,usually in midline of posterior scalp. Lesions sometimes have atrophicskin covering and generally heal in a scar without hair.Inheritance pattern is usually autosomaldominant but may be autosomal recessive. Congenital Triangular Alopecia
May go unnoticed until 2–3 yrs ofage. Triangular area of alopecia, which may be unilateral or bilateral,overlies frontotemporal suture and impinges on anterior hairline.Area remains unchanged throughout life.
Diffuse
Ectodermal Dysplasias
In X-linkedanhidrotic form of ectodermal dysplasia, affected boys have alopecia,hypotrichosis, lack of sweating due to absent sweat glands, andabnormal teeth (small pointed incisors or absence of teeth). Skinbiopsy that shows absence of sweat glands is confirmatory.Autosomal-dominant hidrotic form ischaracterized by variable focal alopecia or loss of all scalp hair,severe nail dystrophy (thick and brittle nails), normal sweating,and normal teeth. Gene locus has been mapped to chromosome 13q12.Rare type of ectodermal dysplasia iscartilage-hair hypoplasia, autosomal-recessive disorder of incompletepenetrance, in which individuals have fine, sparse hair; metaphysealdysplasia resulting in short stature; and immunodeficiency. See Chap. 53, Recurrent Infection. Hair Shaft Defects
Trichorrhexisnodosa produces hair that breaks easily, leaving broken stubs andareas of alopecia. Microscopic exam shows hair that looks like 2paint brushes pushed together. May be associated with argininosuccinicaciduria and Menkes disease.Pili torti refers to dry, lusterless,fragile hair, which can occur as autosomal-recessive disorder ormay be associated with Menkes disease. Microscopic exam revealsflattened hair shaft twisted on its own axis.Monilethrix is autosomal-dominant disordercharacterized by scalp hair breakage. Microscopic exam shows typicallybeaded hair.Scalp and body hair appears dry, lusterless,and fragile with trichorrhexis invaginata. Microscopic exam revealsbamboolike ball and cup joints. Can occur in Netherton disease,which is characterized by ichthyosis. Loose Anagen Hair Syndrome
Autosomal-dominant disorder with variableexpression in which hair is sparse, slow growing, usually fair colored,and easily pulled from scalp. Hair shafts have reduced caliber.Electron microscopy shows slight flattening and longitudinal groovingof hair.
Congenital Hypothyroidism
Scalp hair may be sparse and brittle. See Chap. 23, Growth Deficiency: Weight and Height.
Acquired Hair Loss
Localized
Traction Alopecia
Excessivetension on hair shafts can cause hair loss, and most cases are relatedto hair care. Broken hairs of various sizes are seen in areas ofalopecia.Friction alopecia occurs from repeatedrubbing of scalp and is seen in infants who lie for prolonged timeon their backs or who repetitively rub back of their heads as dailyritual. Trichotillomania
Compulsivepulling of scalp hair, eyebrows, or eyelashes. Habitual, possiblyrelated to underlying anxiety.Irregular patches of hair loss occur,while residual hairs of varying length remain.Psychologic treatment is sometimesnecessary. Tinea Capitis
T. tonsuransis most common cause of tinea capitis in North America. M. canisacquired from kittens or puppies may also cause tinea capitis. Severalpresentations may occur:Circumscribed areas of hair loss with hairsbroken off at follicular orifice (black dot sign) and no other scalpchangeDiffuse fine scaling in dandruff-likepattern without obvious broken off hairsMultiple patches of hair loss withindistinct margins accompanied by kerion (boggy, erythematous nodulewith superficial pustules)Multiple kerions Diagnosis may be confirmed by KOH preparationor fungal culture. Injury
Physical trauma or burns severe enough tocause scarring can produce localized alopecia.
Alopecia Areata
Autosomal-dominantdisorder in which complete or almost complete hair loss occurs incircumscribed areas. Autoimmune mechanism is thought to be responsible.Loss of body hair, eyebrows, and eyelashesalso may be seen. Patches of hair loss do not have any hair exceptperhaps some loose ones at margins. In most cases of incompletehair loss, regrowth of hair usually occurs within 1 yr. With extensivehair loss, prognosis is uncertain.Diagnosis can be confirmed by biopsy. Other
Localizedscalp lesions sometimes occur with varicella, pyoderma, lichen planus,discoid lupus erythematosus, secondary syphilis, and psoriasis.See Chap. 60, Skin Lesions andRashes.Morphea is scleroderma localized toskin. Scalp lesions are linear or oval and often extend from foreheadinto frontal scalp, producing scarring hair loss. Skin is immobile,shiny, hypopigmented, and often surrounded by purplish border. Skinbiopsy is diagnostic. Diffuse
Telogen Effluvium
Characterizedby hair loss resulting from various stresses that cause cessationof hair growth. Such stresses include febrile or chronic illness,general anesthesia, severe injury, drugs (propranolol, coumadin,heparin, valproic acid), and psychologic disturbances. Time betweenstress and hair loss is 2–4 mos.Telogen hairs have absent or fragmentedexternal root sheaths, which often lack pigment. Root of hair isnarrower than shaft and is often curved.Presence of >25% oftelogen hairs in sample of plucked hairs is diagnostic. Anagen Effluvium
Temporaryarrest of follicular activity produced by a substance or physicalmodality that is toxic to hair follicle. Onset of increased sheddingand hair loss usually occurs 1–2 wks after exposure.Anagen hair has pigmented core andbulbous root, which is larger in diameter than hair shaft.Most common causes of anagen hair lossare chemotherapeutic agents that interfere with hair growth (methotrexate,5-fluorouracil, nitrogen mustard, chlorambucil, vincristine, cyclophosphamide,actinomycin D, vinblastine) and radiation that damages growing hair.History and microscopic observationthat most of the lost hairs are in anagen phase confirm diagnosis. Androgenetic Alopecia
In boys, there is thinning over vertex andbifrontal areas of scalp, whereas in girls the crown thins. Geneticallydetermined and potentiated by androgens.
Diagnostic Approach
Diagnosisof hair loss in children can often be made by history and physicalexam.About 90–95% of casesinvolve acquired localized hair loss with tinea capitis, traction alopecia,trichotillomania, or alopecia areata.Diagnosis of tinea capitis is usuallyclinical, but if diagnosis is uncertain, KOH preparation can beperformed. If results are negative, fungal culture should be performed.Most diffuse hair loss is acquired,and most common causes are anagen effluvium (usually chemotherapeuticagents) and telogen effluvium. History and microscopic exam of hairis usually diagnostic of anagen or telogen effluvium.Hair shaft defects also can cause diffusehair loss, but they are rare. Diagnosis is made by microscopic examof hair.Skin biopsy is often necessary in diagnosisof unusual lesions (e.g., aplasia cutis congenita, lichen planus,discoid lupus erythematosus, and morphea). References
- Atton AV, Tunnessen WW Jr. Alopecia inchildren: the most common causes. Pediatr Rev 1990;12:25–30.
- Datloff J, Esterly NB. A system for sorting out pediatricalopecia. Contemp Pediatr 1986;3:53–72.
- Harper J, et al., eds. Textbook of pediatric dermatology.Oxford: Blackwell Science, 2000.
- Levy ML. Disorders of the hair and scalp in children.Pediatr Clin North Am 1991;38:905–919.
- Online Mendelian Inheritance in Man (OMIM). McKusick-NathansInstitute for Genetic Medicine, Johns Hopkins University (Baltimore,MD) and National Center for Biotechnology Information, NationalLibrary of Medicine (Bethesda, MD), 2000. World Wide Web URL: http://www.ncbi.nlm.nih.gov/omim.
- Tunnessen WW Jr. Signs and symptoms in pediatrics,3rd ed. Philadelphia: Lippincott Williams & Wilkins, 1999.
- Verbov J. Hair loss in children. Arch Dis Child 1993;68:702–706.
- Weston WL, et al. Color textbook of pediatric dermatology,2nd ed. St. Louis: Mosby-Year Book, 1996.
Book Source Details
- Book Title: The Diagnostic Approach to Symptoms and Signs in Pediatrics
- Author(s): Paul S. Bellet
- Year of Publication: 2006
- Copyright Details: The Diagnostic Approach to Symptoms and Signs in Pediatrics, Copyright © 2006 Lippincott Williams & Wilkins.
Other Book Chapters Related to Hair loss
Read excerpts from these other book chapters related to Hair loss:
Medical Books Excerpts
- ALOPECIA
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
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- Alopecia
- "In A Page: Pediatric Signs and Symptoms" (2007)
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- BALDNESS
- "Differential Diagnosis in Primary Care" (2007)
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- Alopecia
- "A Pocket Manual of Differential Diagnosis" (1999)
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- Alopecia
- "Professional Guide to Diseases (Eighth Edition)" (2005)
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- Alopecia
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
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- Alopecia
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
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- Hair Loss
- "The Diagnostic Approach to Symptoms and Signs in Pediatrics" (2006)
- [ read ]
- BALDNESS
- "Differential Diagnosis in Primary Care" (2007)
- [ read ]
Copyright Details: The Diagnostic Approach to Symptoms and Signs in Pediatrics, Copyright © 2008 Williams & Wilkins.
More About Causes of Hair loss
» Next page: BALDNESS (Differential Diagnosis in Primary Care)
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