CLASSIFICATION OF ALOPECIA

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SCARRING ALOPECIA

Also known as cicatricial alopecia, is hair loss that can ocure as a result of complications from another condition. In this type of alopecia the hair follicle is completely destroyed. Conditions that can cause scarring alopecia are:

  1. Growth disorders and inherited diseases (epidermal nevi-darier disease)etc
  2. Damages from natural causes ( mechanical trauma-burns ) etc
  3. Infections microbial or viral
  4. Neoplasia
  5. Various other skin diseases of unknown etiology.

NON -SCARRING ALOPECIA

CLASSIFICATION

  • Physiologic alopecia: daily hair loss 50-150 hair(NORMAL) ,as a result of reaction of the hair follicles to seasonal environmental influences.
  • Androgenic alopecia: (male- and female-pattern baldness):Most common cause of hair loss. Localized and systemic hair loss, which usually begins with the front parietal scalp and then the vertex. Male-pattern baldness in females is indicative of androgen excess and may be accompanied by hirsutism in mild cases and virilization in more serious ones. Female-pattern baldness is similar but more diffuse, usually without complete baldness and maintaining the frontal hairline.
  • Alopecia areata:Second most common presentation of non-scaring alopecia Hair is rapidly lost in circular or oval patches or less commonly, may be diffuse involving the scalp. May include facial or body hair. May be episodic or persistent
  • Telogen effluvium: Diffuse alopecia following a triggering event, such as surgery, childbirth, emotional stress, hormonal fluctuations, or medication use. Hair loss occurs approximately 3 months after the event. Usually affects less than 50% of the scalp. Recovery is often complete once triggering factor is resolved.
  • Anagen effluvium: Diffuse hair loss that occurs as a result of exposure to certain toxins. Following toxic exposure, hair growth is abruptly interrupted and anagen hair is shed after 1 to 4 weeks. Rapidly affects 80% to 90% of the scalp. Complete recovery can be expected once triggering factor are removed
  • Traction alopecia: Hair loss that is caused by direct insult to hair. Associated with such styling techniques as using hot rollers or braiding. Pattern of hair loss may relate directly to technique used. More common in black patients. If continued, may progress to scarring alopecia
  • Trichotillomania (subtype of traction alopecia): Self-inflicted loss of hair, typically from front parietal region progressing backwards. Regrowth of up to 1.5 cm may also be visible before hair is long enough to pull again
  • Tinea capitis: Fungal infection that causes hairs to break off close to the scalp leaving a 'black dot' effect. Often a result of a secondary bacterial infection Scalp is intensely pruritic or painful. Predominantly affects children; more commonly, inner city African populations.
  • Alopecia neoplastica: Hard nodules/tumors or flat unchanged skin with loss of hair. Can be secondary to primary skin cancer of scalp or metastatic tumor
  • Alopecia mucinosa: A form of localized hair loss sometimes seen in patients with mycosis fungoides, but may occur alone.

ANDROGENIC ALOPECIA

Genetically determined ( reason:Inheritance ) 95%for men and 75% for women
  • Development is related to age and presence of androgenic hormones/receptors
  • Alopecia areata: Although exact etiology is unknown, there is a genetic predisposition, and consensus favors an autoimmune response
  • Telogen effluvium: Normal hair cycle is interrupted so that anagen (growing) hairs are abruptly converted into telogen (resting) hairs, which are subsequently shed after 2 to 4 months
  • Hypothyroidism and hyperthyroidism
  • Postpartum, post-illness
  • Surgery with general anesthesia
  • Nutritional deficiency, particularly with iron or zinc
  • Psychological stress
  • Most telogen effluvium from medications is caused by retinoids, β-blockers, calcium channel blockers, antidepressants, and nonsteroidal anti-inflammatory drugs (including ibuprofen)
  • Tinea capitis: Ringworm of the scalp in which dermatophyte fungus invades the hair shaft. The most likely dermatophytes include
  • Microsporum (from cats and dogs)

RISK FACTORS

  1. Family history of baldness
  2. Advanced age
  3. Physical stress
  4. Psychological stress
  5. Pregnancy
  6. Regular use of aggressive hair-styling techniques
  7. Poor nutrition
  8. Rapid weight loss
  9. Restrictive diets (eg, low carbohydrate, low fat)

EPIDEMIOLOGY

Incidence and prevalence:

  • About 25% of men aged 25 years have some degree of clinically apparent androgenic alopecia
  • About 42% of men develop androgenic alopecia
  • About 2% to 3% of the general population develops alopecia areata