Alopecia – AMBOSS

Final up to date: November 22, 2020


Alopecia is the lack of hair from any hair-bearing space of the physique, however most frequently the scalp. It might be congenital or acquired, circumscribed or diffuse, and cicatricial or nonscarring. Androgenetic alopecia, a sort of diffuse, nonscarring, acquired alopecia, is the commonest, affecting > 70% of the overall inhabitants by 70 years of age. Alopecia areata, an acquired, circumscribed, nonscarring alopecia, is the following most typical kind. Scientific prognosis is normally potential. In ambiguous circumstances, prognosis is aided by microscopic examination of the hair, trichograms, and scalp biopsy. Therapy will depend on the kind of alopecia and consists of long-term (no less than 1 yr) use of topical minoxidil, corticosteroids (topical, intralesional, or oral), or antiandrogens. Surgical procedure (hair transplant) or camouflaging methods are used when medical remedy fails. The prognosis is variable and will depend on the etiology and severity of hair loss.



  • Alopecia: : lack of hair (baldness)
  • Effluvium : means of hair loss
  • Atrichia : inherited hair loss
  • Hypotrichosis : congenital sparse hair, which is normally related to syndromes resembling:

Phases of hair development

  • Anagen section: section of energetic development
  • Telogen section: resting section
  • Catagen section: section of follicular regression


Based on etiology (congenital/acquired) and sample (diffuse/circumscribed)

Based on the presence of scarring

  • Cicatricial (scarring) alopecia

    • Brocq pseudopelade

      • Seen in girls 30–55 years of age
      • Irregular areas of irreversible hair loss, which develop into scarred areas at a later stage
    • Lichen planopilaris
    • Frontal fibrosing alopecia (a progressive type of frontotemporal hair loss related to native scarring)
    • Central centrifugal cicatricial alopecia

      • Alopecia that begins on the crown and spreads outwards
      • Happens virtually completely in black girls > 50 years
    • Pores and skin circumstances inflicting scarring alopecia; : ichthyosis, dyskeratosis, discoid lupus erythematosus
    • Acquired scarring alopecia (e.g., through viral illnesses, mycoses, burns, chemical burns)
  • Nonscarring alopecia


The prognosis is commonly clear from the affected person historical past and bodily examination; nevertheless, there are a number of checks that enable affirmation of prognosis.

  • Hair pull take a look at: About 50 strands of hair are calmly tugged away from the scalp; if > 5 strands might be pulled out, the take a look at is constructive.
  • Dermoscopy: examination of the scalp pores and skin, follicle measurement, and hair shaft diameter by magnification
  • Microscopic examination: carried out on hair follicles and shaft to find out the section of hair development (anagen, telogen) and structural abnormalities of the shaft
  • Scalp biopsies (carried out from websites of energetic illness): to substantiate the prognosis of cicatricial alopecia
  • Trichograms: aids prognosis and prognosis of nonscarring alopecia


Diffuse alopecia

Congenital diffuse alopecia

  • Trichorrhexis nodosa: A hair shaft deformity characterised by the event of weak factors within the shaft on account of bodily/chemical trauma in genetically predisposed people.
  • Pili torti: The hair shaft is flattened and has a number of twists which result in fragile hair that breaks simply.
  • Monilethrix (beaded hair): Autosomal dominant dysfunction with beaded hair shafts which break simply, near the scalp, just a few months after beginning.
  • Genetic syndromes: Menkes illness, Netherton’s syndrome, and so forth.

Acquired diffuse alopecia

Androgenetic alopecia

  • Definition: a progressive, nonscarring alopecia that impacts the areas of the scalp with probably the most androgen-sensitive hair follicles, leading to a attribute sample of balding (bitemporal scalp in males and vertex and frontal scalp in girls).
  • Epidemiology

    • Most typical kind of alopecia
    • Prevalence: Will increase with age
    • Intercourse: ♂ > ♀ (however quite common in girls as effectively)
    • Age at onset: puberty in males; menopause in females
    • Ethnicity: extra widespread in white populations
  • Etiology
  • Pathophysiology
  • Differential prognosis
Options and therapy of androgenetic alopecia in women and men
Males (male sample baldness) Girls (feminine sample baldness)
Scientific options
  • Gradual, nonscarring hair loss

    • Bitemporal “M” sample of recession
    • Could also be adopted by hair loss on the vertex of the scalp
    • 10% of males have a feminine sample of balding.
  • Follicular miniaturization is seen within the affected elements
  • Gradual, nonscarring hair loss
  • Begins on the vertex
  • Progresses to a extra diffuse hair thinning of the whole scalp
  • First-line therapies
  • Hair transplant surgical procedure: Follicular models from the occipital scalp are extracted (both as small models or as a linear strip), divided into small models, and implanted into the bald areas.
  • Camouflage: keratin fibers, hair dyes, toupées, and so forth.
  • 2% Minoxidil: first-line therapy
  • Oral antiandrogens
  • Surgical procedure and camouflage

Telogen effluvium

  • Etiology

    • Endocrine: hypothyroidism, hypopituitarism, hypoparathyroidism, diabetes mellitus.
    • Medicine: anabolic steroids, antithyroid medicine, heparin, coumarin, antimetabolites (chemotherapy), oral contraceptives, and so forth.
    • Dietary: hypervitaminosis A, zinc deficiency, malnutrition states
    • Stress: main surgical procedure, sepsis, after childbirth (telogen gravidarum), acute or persistent sickness (e.g., systemic lupus erythematosus), extreme psychological stress
  • Mechanism: The telogen (resting) section of hair development predominates → untimely shedding of the resting hair follicles → diffuse, nonscarring hair loss
  • Scientific options

    • Hair density reduces by
    • Doesn’t progress to finish baldness.
  • Analysis

    • Scientific; scalp biopsy if unsure (hardly ever mandatory)
    • Hair-pluck take a look at: ∼ 50% of hairs are within the telogen section (regular: ).
    • Checks to find out underlying situation
  • Therapy: reassurance and handle underlying situation

Anagen effluvium

  • Etiology
  • Mechanism: Interruption of the anagen (mitotic) section → abrupt lack of ∼ 90% of hair (inside days of publicity to the causative issue)


Circumscribed alopecia

  • Temporal triangular alopecia

    • A well-defined oval/triangular patch of alopecia within the temporal a part of the scalp
    • Seen earlier than 5 years of age
    • Mimics alopecia areata and is differentiated from it by the presence of vellus hair and the absence of exclamation level hair
    • Therapy (if mandatory): hair transplant/surgical excision
  • Nevus sebaceus
  • Aplasia cutis congenita

    • Intra-uterine developmental disruption of 1/extra layers of the scalp
    • Part of the scalp is lacking at beginning, which, on therapeutic, causes scarred, hairless patch
    • Therapy
      • Small lesions: no therapy
      • Massive lesions: surgical excision + major closure/restore (with assist of tissue expanders and pores and skin flaps)

Alopecia areata

  • Definition: Hair loss in effectively demarcated patches on account of immune-mediated irritation of hair follicles
  • Epidemiology
  • Etiology
  • Scientific options

    • Abrupt onset (inside weeks)
    • Clean, round, effectively outlined patches of hair loss with out scarring
    • Exclamation level hairs
    • Numerous patterns of distribution
      • Ophiasis: hair loss localized to the again and sides of the scalp
      • Sisiapho: sparing of the perimeters and again of the scalp
      • Intensive alopecia areata: hair loss affecting > 50% of the scalp
      • Alopecia universalis : All hair-bearing websites are affected (mimics telogen effluvium).
      • Alopecia totalis: Full baldness
    • Nail involvement (as much as 40% of circumstances): nail pitting, onycholysis, Beau traces, and so forth.
    • Different autoimmune issues could also be current (e.g., vitiligo, autoimmune issues of the thryoid, and so forth.)
  • Diagnostics

    • Normally medical prognosis
    • Biopsy, histology, and trichogram could also be carried out to substantiate the prognosis
  • Differential prognosis
  • Therapy

    • Intralesional steroids (triamcinolone)
    • Topical immunotherapy (DCP (diphenylcyclopropenone) or SADBE (squaric acid dibutyl ester)
    • PUVA therapy (Psoralen + UVA)
  • Prognosis: poor for alopecia universalis and totalis

Traction alopecia

  • Definition: Hair loss on account of persistent traction/pressure on the hair follicles, largely on the frontal and temporal scalp
  • Etiology: Hairstyles involving tying the hair tightly
  • Therapy



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