Alopecia

Notes

## Basic introduction

  • Alopecia (baldness) is the loss of hair from part of the head or the body
  • Stages of hair growth:
  • Anagen (growing phase, longest period)
  • Catagen (transitional apoptotic phase)
  • Telogen (resting phase)
  • Exogen (hair falling at the end of the resting phase)

## Types of alopecia

  • Androgenetic-male pattern-alopecia
  • It is also known as “common baldness”
  • It is caused by genetics and male hormones
  • Female-pattern hair loss
  • The cause is not known
  • Alopecia areata or totalis
  • It is an autoimmune disease in which autoantibodies attack hair follicles
  • It is common in teenagers
  • Frontal fibrosing alopecia
  • It is scarring hair loss characterized by progressive recession of the frontotemporal hairline, with or without progressive loss of eyebrows
  • Telogen effluvium
  • It is caused by a physically or psychologically stressful event such as pregnancy
  • Anagen effluvium
  • It occurs when the growing phase of the hair (anagen) is interrupted
  • The loss can be fast and extensive
  • It is mainly associated with chemotherapeutic agents
  • Systemic disease - associated alopecia
  • Anemia and other types of malnutrition
  • HIV
  • Hypothyroidism
  • Hyperprolactinemia
  • Diabetes
  • Trauma related alopecia
  • Hair loss with scaling and/ or inflammation due to:
  • Fungal infections
  • Lichen planopilaris
  • Lupus erythematosus
  • Sarcoidosis

## Statistics

  • Pattern hair loss (male and female) by age 50 affects about 50% of males and 25% of females
  • Approximately 2% of global population develop alopecia areata in their life time
Symptoms
  • Loss of hair from part of the head or the body
  • Alopecia areata is characterized by:
  • Distinct and circular area of hair loss
  • Short and broken hairs
  • It is sometimes associated with other autoimmune conditions e.g. rheumatoid arthritis, thyroid disease, vitiligo, lupus, and ulcerative colitis
  • Hair loss due to Lichen planopilaris and Lupus erythematosus that is characterized by:
  • Erythema
  • Pruritus
  • Scaling
  • Alopecia universalis that is characterized by the loss of the hair on scalp and the rest of the body
  • Trichotillomania is characterized by:
  • Asymmetric and irregular hair loss pattern
  • Hair loss due to infections is characterized by the presence of pustules
  • Hair loss due to secondary syphilis that is characterized by:
  • Patchy hair loss
  • Hairs that appear moth-eaten
Diagnosis
  • Clinical review
  • Pull test
  • Pluck test
  • Daily hair count
  • Scalp biopsy
  • Trichoscopy
Differential
  • Trichotillomania (compulsive hair pulling)
Prevention

There is generally very little that can be done to prevent alopecia

Reference

a. C. (2015). Selected Disorders of Skin Appendages Vary,—Acne, Alopecia, Hyperhidrosis. Medical Clinics of North America, 99(6), 1195-1211.

b. Messenger, A. G., McKillop, J., Farrant, P., McDonagh, A. J., & Sladden, M. (2012). British Association of Dermatologists’ guidelines for the management of alopecia areata 2012. British journal of dermatology, 166(5), 916-926.

Management
  • Androgenetic-male pattern-alopecia[b]
  • Minoxidil [as long as it is used]
  • Anti-androgens 5α-reductase inhibitors e.g. finasteride; cyproterone
  • Alopecia areata or totalis
  • Intralesional injection of corticosteroids
  • Photochemotherapy with ultra-violet A radiation [PUVA] with systemic or topical psoralens
  • Topical minoxidil
  • Allergic sensitization with dipencyprone.
  • Up to 80% of patients with limited patchy hair loss of short duration experience spontaneous remission
  • Frontal fibrosing alopecia
  • There is no effective treatment
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