alopecia
ALOPECIA

Alopecia is an involuntary loss of hair usually in the scalp that may occur anywhere over the body.
Scarring alopecia is severe inflammation of the hair follicle result in irreversible damage.
Non-scarring alopecias are reversible.
Alopecia may  be abrupt or gradual in onset.
Most common causes include androgenic alopecia (male & female pattern baldness) & alopecia areata.
History should be reviewed for medications, severe diet restriction, vitamin A supplementation, thyroid symptoms, concomitant illness & stress factor.

Alopecia Diagnosis

History

Androgenic alopecia in men/women
  • Some do not have a family history
  • An androgen-dependent trait
Alopecia areata
  • Family history of alopecia
  • Patients often give a history of emotional trauma/stress prior to its onset
  • Usually rapid hair loss in a well-defined, typically round area
  • Patients complain of 1-4 cm2 of hair loss on the scalp
    • Patch is usually clean-looking without scaling
  • May be asymptomatic, but some patients experience paresthesias with pruritus, burning sensation, pain or tenderness prior to loss of hair

Laboratory Tests

Androgenic alopecia in males/females

  • Rarely indicated for MPHL and females with normal menstrual cycle
  • Include pull test and examination of facial and body hair and nails
    • Pull test must be performed in the right and left parietal areas, frontal and occipital areas and in visibly affected areas
      • Hair pull test is positive in active early hair loss but negative in long standing hair loss
  • If with evidence of androgen excess in FPHL, consider total testosterone, free testosterone, dehydroepiandrosterone sulfate (DHEAS), prolactin levels
  • If without evidence of androgen excess: Rule out thyroid disease, syphilis, iron deficiency and systematic lupus erythematosus (SLE) as cause of hair loss
  • Biopsy is sometimes necessary for FPHL to exclude chronic telogen effluvium, diffuse alopecia areata or cicatricial hair loss
  • Trichoscopy (also known as dermoscopy) should be considered in doubtful cases
    • Features typical for androgenic alopecia include vellus hairs >10%, increased percentage of follicular units with only 1 hair shaft, hair shaft thickness heterogeneity of ≥20%, yellow dots, perifollicular discoloration, empty follicles, circle hair and honey comb pigment pattern

Alopecia areata

  • Diagnosis is usually clinical
  • Hair pull test may be positive at the margins which is indicative of active disease
  • Trichoscopy (dermoscopy) may be helpful for visualizing findings consistent with alopecia areata
    • Features typical of alopecia areata include short vellus hairs, black dots, yellow dots, tapering hairs and broken hairs
  • Patch biopsy of the scalp in rare difficult cases
  • Thyroid stimulating hormone (TSH) level determination is routinely performed by many physicians to rule out any related thyroid abnormality

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