Alopecia: Difference between revisions

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== History and Symptoms ==
== 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<br>


== Physical Examination ==
== Physical Examination ==

Revision as of 13:07, 29 August 2012

Alopecia
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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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
  • Diffuse hair loss peaks 3-4 months after inciting event
  • Up to 30% of hairs must be lost before cosmetically apparent
  • Anagen effluvium

Focal

  • 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:
  • 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
  • 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

Complete Differential Diagnosis for Alopecia

History and Symptoms

Physical Examination

Appearance of the Patient

Laboratory Findings

Treatment

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


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