Alopecia • Anoop Agrawal, M.D. • Baylor College of Medicine • Med-Peds Continuity Clinic
Objectives • Review normal hair growth physiology • Know how to evaluate a patient with alopecia • Know the causes of alopecia • Be familiar with available treatment options
Physiology of normal hair growth • A human is born with all of their terminal hair follicles. • Hair growth is a cyclical process: • Anagen - the growth phase, lasts 2 to 3 years • Catagen - the involutional phase, lasts 2 to 3 weeks • Telogen - the resting phase, lasts 3 to 4 months
Physiology continued • Hair follicle is released from the shaft at the end of the telogen phase and the cycle begins anew. • At any given time, 80 to 90% of follicles are in anagen, 5 to 10% are in telogen, 1 to 3% are in catagen. • Up to 75 hairs are shed each day.
Evaluation of Hair Loss • History: • Onset - gradual vs. rapid (‘handfuls of hair’) • History of physical, mental or emotional stressors in the past 3 to 6 months • Hair thinning vs. shedding • Pattern of hair loss - focal vs. diffuse
Evaluation continued • Physical exam: • Scarring vs. Nonscarring • Scarring alopecia refers to hair loss associated with fibrosis and permanent damage to hair follicles • Examples: bullous disease, discoid lupus, chemical alopecia, dissecting cellulitis, tumors, lichen planopilaris
Evaluation cont... • Physical: • Pattern of hair loss - classic ‘M’ or central pattern vs. diffuse vs. focal areas
Name the types of alopecia • Androgenetic alopecia • Alopecia areata • Telogen effluvium • Traumatic alopecia: traction alopecia and trichotillomania • Cicatricial Alopeica (irreversible alopecia - mostly the etiologies resulting in scarring)
Androgenetic Alopecia in men • Key to diagnosis: hair thinning in distinct pattern - ‘M’ shaped pattern in men (temporal, crown, known as male pattern baldness); gradual onset • Onset of changes begin in puberty with androgens shortening the anagen phase and promoting follicular miniaturization • Treatment: Minoxidil (topical - 5% better than 2%), or finasteride 1mg qd; both require continued use to maintain growth
Androgenetic Alopecia: Stages in Men Stage 4 Stage 5 Stage 6 Stage 7
Androgenetic Alopecia in women • In women, hair thinning occurs in central scalp • If the patient also has clinical signs of hirsutism, menstrual irregularities, acne, infertility, etc, then need to evaluate for hyperandrogenism. • Treatment options: Minoxidil 2%; also estrogens and spironolactone - these two slow hair loss, do not promote regrowth
Alopecia Areata • Incidence of 1 in 1000 people, cause is unknown though an autoimmune factor is suspected. • Rarely, other autoimmune diseases such as vitiligo, thyroiditis or pernicious anemia may be associated. • 20 % have a family history • Key features: smooth, discrete, circular areas of complete hair loss, exclamation point hairs!
Alopecia Areata • Other keys: black dots of broken off hairs found at expanding edges, multiple patches can coalesce to form bizarre shapes • Alopecia totalis - hair loss of entire scalp • Alopecia universalis - hair loss of entire scalp and body • Prognosis: 90% of the hair loss will regrow within 2 years; however, recurrence occurs in 1/3 of cases
What is the treament for Alopecia areata? • Intralesional corticosteroids - new hair growth can be seen within 4 weeks • Topical corticosteroids - better for totalis • Anthralin - an immunomodulator, nonsteroid, safe for children and those with universalis • Topical immunotherapy - for chronic severe cases
Telogen Effluvium • Keys to diagnosis: hair loss is diffuse, onset abrupt • Pt has experienced a stressful or inciting event 3-4 months prior. The event disrupts normal hair growth cycle, more hair is prematurely shifted into the telogen phase. • Consider events such as pregnancy, weight loss, illness, surgery, psychological trauma... • The pull test - grab a few dozen hair follicles and gently pull - more than 5 telogen (club) hairs is abnormal.
Telogen Effluvium • No therapy required, condition fully reversible • Other causes of diffuse hair loss to consider if an inciting event cannot be identified: medications, thyroid disease, connective tissue disease, syphilis (moth-eaten appearance), hypervitamintosis A, nutritional deficiency of zinc or biotin. • Anagen Effluvium - involves growing hair, thus results in a loss of 80 to 90% of hair; seen with chemotherapy.
12 yo male with sudden loss of hair 2 weeks ago, what is the diagnosis? • Trichotillomania - the intentional pulling of hair • characterized by hairs of varying lengths and stubble
And don’t forget Cicatricial alopecia • Results in scarring, often irreversible alopecia thought due to stem-cell failure at base of follicle, causes include: • autoimmune diseases - discoid lupus, lichen planopilaris (variant of lichen planus) • dissecting cellulitis, folliculitis decalvans • follicular degeneration syndrome in blacks
References • www.dermatology.org/hairinfo, “Practical Management of Hair Loss”, accessed February 15, 2009. • Springer K, et al. “Common Hair Loss Disorders”, American Family Physician, July 1, 2003, 68:1:93-102.