Hair Loss: Common Causes and Treatment

T. Grant Phillips, MD; W. Paul Slomiany, MD; Robert Allison, DO

Am Fam Physician. 2017;96(6):371-378.

Physiology of Hair Growth

Hair grows in three phases: anagen (active growing, about 90 % of hairs), catagen (degeneration, less than 10% of hairs) and telogen (resting, 5% to 10% of hairs). Hair is shed during the telogen phase.

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Abstract and Introduction
Physiology of Hair Growth
Approach to the Patient with Nonscarring Alopecia
Specific Disorders
References
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Table 1. Summary of Nonscarring Alopecia
Type	Significant features	Treatment and comments
Alopecia areata	Acute, patchy hair loss; examination shows short, vellus hairs, yellow or black dots, and broken hair shafts	Intralesional triamcinolone acetonide injected intradermally High rate of spontaneous remission
Anagen effluvium	Diffuse hair loss days to weeks after exposure to a chemotherapeutic agent; incidence after chemotherapy is estimated at 65%	No pharmacologic intervention has been proven effective; scalp cooling not recommended Minoxidil may help during regrowth period
Androgenetic alopecia	Family history of hair loss; gradually progressive course Men: bitemporal thinning of the frontal and vertex scalp, complete hair loss with some hair at the occiput and temporal fringes Women: diffuse hair thinning of the vertex with sparing of the frontal hairline	Men: topical minoxidil (2% or 5% solution) Women: topical minoxidil (2% solution) Treatment should continue indefinitely because hair loss reoccurs when treatment is discontinued Adverse effects include hypertrichosis (excessive hair growth for age, sex, and race) and irritant or contact dermatitis
Telogen effluvium	Clumps of hair come out in the shower or in hairbrush; associated with physiologic or emotional stress	Treatment involves removing the underlying cause and providing reassurance Condition is usually self-limited and resolves within two to six months
Tinea capitis	Dermatophyte infection of the hair shaft and follicles; patients present with patchy alopecia with or without scaling	Requires systemic treatment because topical antifungals do not penetrate hair follicles Trichophyton species: oral terbinafine (Lamisil), itraconazole (Sporanox), fluconazole (Diflucan), or griseofulvin Microsporum species: griseofulvin
Trichorrhexis nodosa	Hairs break secondary to trauma or because of fragile hair (congenital or genetic); causative traumas include excessive brushing, heat application, hairstyles that pull on hairs, and conditions that cause excessive scalp scratching	Stop offending actions
Trichotillomania	Patches of alopecia, typically frontoparietal, that progress backward and may include the eyelashes and eyebrows	Optimal treatment is unknown; strong evidence is lacking for selective serotonin reuptake inhibitors; cognitive behavior therapy with habit reversal and medications may be more effective than either approach alone Psychiatric referral may be indicated

Table 2. Common Findings, Related Diagnoses, and Workup for Hair Loss
Common findings	Related diagnosis	Diagnostic workup and comments
Abrupt onset of hair loss	Telogen effluvium related to a specific event	Inquire about inciting event
Gradual onset of hair loss	Alopecia areata	History and physical examination findings are diagnostic
		Pull test: increased telogen-to-anagen ratio (greater than the normal ratio of 1:10)
	Androgenetic alopecia	Family history and specific patterns are important
	Scarring alopecias	Refer if scarring is suspected
Diffuse hair loss	Alopecia totalis if more than scalp is involved	Consider referral
	Systemic disease (e.g., hypothyroidism, iron deficiency, other nutritional disorder)	Laboratory testing depends on history and physical examination findings: complete blood count, thyroid-stimulating hormone level
	Telogen effluvium	History and physical examination findings are diagnostic
Patchy hair loss	Alopecia areata, trichotillomania	History and physical examination findings are diagnostic
Patchy hair loss	Tinea capitis	Obtain fungal cultures; itching, scaling, pustules, and lymphadenopathy may be present
Male or female pattern	Androgenetic alopecia	History and physical examination findings are diagnostic; scalp appears normal
History of anxiety or psychiatric diseases	Trichotillomania	Obtain psychiatric history; patient may not be forthcoming about pulling hair; pattern and appearance of hair are diagnostic
History of extensive use of hair products or tight hairstyles	Trichorrhexis nodosa	History and physical examination findings are diagnostic; broken hairs seen on slight magnification
Medication use	Several types of hair loss, especially telogen effluvium	If a particular medicine is suspected, a discontinuation trial is reasonable
Recent physical or emotional trauma	Telogen effluvium	History and physical examination findings are diagnostic; scalp appears normal; hair loss may not be obvious
Skin condition	Scarring alopecia, tinea capitis; most nonscarring alopecias are associated with a relatively normal scalp	History and physical examination findings are diagnostic
Systemic symptoms	Related to systemic disease	Laboratory testing depends on history and physical examination findings

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Sort: Key Recommendations for Practice

Clinical recommendation	Evidence rating	References
Topical minoxidil is safe and effective for the treatment of androgenetic alopecia in women.	B	⁵
Alopecia areata can be treated with intralesional corticosteroids.	B	¹¹
Oral terbinafine (Lamisil), itraconazole (Sporanox), fluconazole (Diflucan), or griseofulvin is recommended for treatment of children with tinea capitis caused by Trichophyton infections.	B	²
Cognitive behavior therapy is effective for the treatment of trichotillomania, and medical therapy may be more effective when combined with cognitive behavior therapy.	B	¹⁹

A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to http://www.aafp.org/afpsort.