Alopecia: Difference between revisions
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=== Appearance of the Patient === | === Appearance of the Patient === | ||
== Laboratory Findings == | == Laboratory Findings == | ||
Revision as of 12:11, 29 August 2012
| Alopecia | |
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| Alopecia as male pattern baldness at age 40 | |
| ICD-10 | L65.9 |
| ICD-9 | 704.09 |
| DiseasesDB | 14765 |
| MedlinePlus | 003246 |
| MeSH | D000505 |
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Alopecia Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Alopecia On the Web |
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American Roentgen Ray Society Images of Alopecia |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Atrichia; hair loss
Overview
Alopecia is the resulting condition from the loss of hair, which is termed effluvium. It should be distinguished from baldness, which is the lack of hair, including contexts where that absence is intentional. (In some cases the terms are used interchangeably, and in some conditions such as trichotillomania, where the loss of the hair is due to intentional acts, but the motive for that act is defined as a medical condition, it can be difficult to determine whether the label "alopecia" is appropriate.)
Alopecia is characterized by scarring or non-scarring. Scarring alopecia is caused by numerous dermatologic factors, including glabrous skin (non-hairy), and is very difficult to diagnose and manage. Non-scarring alopecia is characterized by the absence of visible inflammation of the skin involved.
Vocabulary
- Anagen:growth phase, lasts 2-3 years (80-90% of follicles at any given time)
- Catagen:involutional phase, lasts 2-3 weeks (1-3% of follicles)
- Telogen:resting phase, lasts 3-4 months (5-10% of follicles)
- hair released from shaft and shed at end of telogen new cycle begins
- mature root sheath of telogen hair = “club” at proximal end
- Terminal hairs: large shaft diameters, bulbs extend into subcutaneous fat
- Vellus hairs:smaller in caliber and length, less pigmented
- Indeterminate hairs:size/length between that of terminal and vellus hairs
Risk Factors
Pathophysiology & Etiology
Non Scarring
Diffuse
- most common (30-40% of men and women)
- Genetically determined: polygenic with variable penetrance
- Shortening of anagen phase follicular miniaturization
- Men: M-shaped pattern along frontal hairline (temporal loss progresses to midscalp)
- Women: more diffuse, can be difficult to distinguish from telogen effluvium
- Reversible loss of mature, terminal hairs (few hundred per day)
- Stressful event (or medication) triggers transition of more anagen hairs into telogen phase
- Childbirth, fever, severe infection, severe psychologic stress, major surgery, crash diet
- Drugs: heparin, antithyroid agents, anticonvulsants, hormones
- Diffuse hair loss peaks 3-4 months after inciting event
- Up to 30% of hairs must be lost before cosmetically apparent
- Anagen effluvium
- Acute loss of anagen hair = 80-90% of hair
- Occurs 10-14 days after treatment with antimitotic agents (chemo)
Focal
- Alopecia areata: incidence 1/1000
- Smooth, discrete, circular areas of complete hair loss occurring over a few weeks
- Exclamation point hairs: hair root narrower than normal with less pigment
- Can occur on any hair-bearing area; nails may also have proximal pitting
- Usually reversible: regrowth occurs over several months; 90% regrow within 2 years
- Relapse occurs in up to 1/3
- Decreased chance of regrowth/increased risk relapse if:
- Prepubertal onset
- Widespread involvement (alopecia totalis or universalis)
- Duration > 5 years
- History of atopy
- Possible autoimmune mechanism: bx shows T-cell infiltrates around hair follicles
- Positive family history in 20%
- Moth-eaten, patchy pattern of loss (may be diffuse)
- May be associated with skin lesions of secondary syphilis, or may occur in latent stage
- Full hairgrowth occurs after treatment of infection
- Traction alopecia: due to hairstyles that impose chronic tension on hair (braids)
- Hair loss most prominent in areas of greatest tension (margins)
- Fine, vellus hairs present in areas of absent terminal hairs
- Regrowth can occur in early disease (few months-yrs), but not in late disease (years)
- Chemical trauma: repeated use of lye-containing straightening agents or hot oils for styling
- Trichotillomania: bizarre, asymmetric pattern of broken hairs of varying length
Scarring
- uncommon; hair loss is permanent
- erythematous papules, pustules, or scaling centered around follicles
- polytrichia = multiple hair shafts exiting a single enlarged orifice
- eventual obliteration of follicular orifices
- Tinea capitis
- Scaling and inflammation in patchy areas of hair loss, +/- lymphadenopathy
- Usually in children
- KOH prep positive
- Central, centrifugal scarring alopecia (a.k.a. follicular degeneration syndrome, pseudopelade)
- Symmetric involvement of central portion of scalp with outward expansion over months/yrs
- May be associated with pustules (folliculitis decalvans)
- Cause unknown-> emipiric Rx with steroids, antibiotics
- Inflammation with plugged follicles, scale, abnormal scalp pigmentation
- May have discoid lesions elsewhere on body
Diagnosis
- Pull test: firm pull on 20-40 hairs should yield fallout of no more than 1 in 10 hairs
- Increased # telogen hairs with depigmented proximal bulb: telogen effluvium
- Increased # hairs with no bulb: breakage (hair fragility due to exogenous injury)
- Anagen hairs with pigmented root: likely excessive force
- Follicular units: number of hairs produced per follicular orifice
- Threes = normal for ages 20-40
- Twos = normal for ages 40-60
- Ones = normal for ages >60
- Voids = follicular orifices w/o hairs suggests advanced androgenetic alopecia if no scarring
- Testing:minimal
- Medical illness suspected: CBC, TSH, possibly ferritin
- RPR if patchy or unexplained loss
- KOH prep if patchy alopecia with scaling or inflammation
Complete Differential Diagnosis for Alopecia
Non-Scarring Alopecia
- Adrenocortical insufficiency (primary or secondary)
- Anagen effluvium (anagen=growing hair)
- Cushing's syndrome
- Diffuse hair thinning due to metabolic causes
- Hyperthyroidism
- Hypoparathyroidism
- Hypothyroidism
- Pituitary insufficiency
- Secondary syphilis
- Sheehan's syndrome
- Temporary hair loss
- Telogen effluvium (telogen=resting hair)
- Thyroiditis
- Trichotillomania
Scarring Alopecia
- Amyloidosis
- Chronic disciform lupus erythematosis
- Congenital defects
- Discoid Lupus Erythematosus
- Dissecting cellulitis
- Herpes zoster infection
- Infection
- Inflammatory dermatoses
- Lichen planopilaris
- Lymphoma
- Morphea
- Mycosis fungoides
- Neoplasm
- Neurodermatitis
- Physical or chemical agents:
- ACE inhibitors
- Allopurinol
- Androgens
- Anticoagulants
- Anticonvulsants
- Antimycotic agents
- Arsenic
- Azathioprine
- Beta blockers
- Borates
- Cadmium
- Chemotherapeutics
- Chlorambucil
- Cisplatin
- Clofibrate
- Cyclophosphamide
- Cytarabine
- Estrogens
- Fluororacil
- Gentamycin
- Gold compounds
- Heparins
- Indomethacin
- Levodopa
- Linolic acid
- Mercury and derivatives
- Methotrexate
- Niacin
- Oral contraceptives
- Propranolol
- Retinoids
- Salicylates
- Selenium
- Squalenes
- Steroids
- Thallium
- Undecylenic acid
- Vitamin A overdose
- Warfarin
- Pseudofolliculitis barbae
- Psoriasis
- Sarcoidosis
- Scleroderma
- Systemic Lupus Erythematosus
Miscellaneous
- Addison's Disease
- Anemia
- Cancer
- Diabetes Mellitus
- Pneumonia
- Scarlet Fever
- Schmidt's Syndrome
- Stress
- Testicular feminization syndrome
- Turner's Syndrome
- Typhoid fever
- Mechanical effects
- Traction alopecia
- Pressure alopecia
- Alopecia after extended bed rest
- Trichotillomania (compulsion to pull out one’s own hair)
History and Symptoms
- Age
- Childhood: only 2 common diagnoses tinea capitis, alopecia areata
- Adulthood: tinea capitis rare; all the rest possible
- Duration
- <1 year: suggests telogen effluvium if diffuse loss
- >1 year: suggests androgenetic alopecia if diffuse loss
- Pattern of loss
- Shedding: “lots of hair coming out,” may be due to hair breakage or loss by the root
- Thinning: scalp more visible without noticeable hair fallout, suggests androgenetic alopecia
- Family history: may be positive in androgenetic alopecia, alopecia areata
- Grooming practices: can cause hair fragility/breakage
- Chemical treatments (relaxers, perms, bleaching) most damaging; hair dye less so
Traction styling
Physical Examination
Appearance of the Patient
Laboratory Findings
- Viral and bacterial cultures
- Prolactin
- Thyroid function tests
- Iron studies
- Dehydroepiandrosterone-sulfate (DHEA-S)
- Testosterone
- Rapid plasma reagin (RPR)
- Erythrocyte sedimentation rate (ESR)
- Antinuclear antibodies (ANA)
Treatment
- Goal of treatment is to avoid future hair loss.
- Scarring hair loss prevents hair from going back.
- Wigs and hair transplants
- Anagen effluvium
- Telogen effluvium
- Stress the recovery is normal
- Treat underlying cause of alopecia
Acknowledgements
The content on this page was first contributed by: Steven Wiviott, M.D.
References
Alopecia Types - More information about alopecia and the various different types