Alopecia




(1)
Department of Dermatology, University of Pennsylvania, Penn Presbyterian Medical Center Medical Arts Building, Philadelphia, PA, USA

 



9.1 Scarring Alopecia

9.1.1 Inflammatory Scarring Alopecia

9.1.2 Non-Inflammatory Scarring Alopecia

9.2 Non-Scarring Alopecia

9.2.1 Non-Inflammatory Non-Scarring Alopecia

9.2.2 Inflammatory Non-Scarring Alopecia

9.3 Genodermatoses Associated with Alopecia

9.4 Hair Shaft Abnormalities

9.4.1 Structural Abnormalities with Increased Hair Fragility

9.4.2 Structural Abnormalities Without Hair Fragility

9.5 Excess Hair Growth


Abstract

This section focuses on diseases that cause hair loss or hair abnormalities. Clinically, scarring alopecia is suggested by loss of hair follicle ostia and smooth, shiny patches of skin between tufts of hair (like doll’s hairs). Non-scarring alopecias typically retain hair follicles despite loss of hair. With time, however, even non-scarring alopecias may show loss of follicular ostia. On pathology, scarring alopecias may show changes from minimal inflammation to perifollicular fibrosis and ultimately true follicular scars.

The hair cycle consists of: anagen/growth phase (~2–6 years), catagen/transition phase (~3 weeks), telogen/release phase (~3 months); mnemonic: rule of 3s, 3 years (anagen), 3 weeks (catagen), 3 months (telogen)


Keywords
AlopeciaScarring alopeciaNon-scarring alopecia



9.1 Scarring Alopecia



9.1.1 Inflammatory Scarring Alopecia




(a)

Lymphoid scarring alopecia

I.

Discoid lupus (DLE)



  • Classically hyperkeratotic plaques with follicular plugging and scarring alopecia; typically on face, scalp, conchal bowls of ears


  • “Carpet tack sign” = horny plugs on undersurface when scale removed (non-specific)


  • “Lupus hairs” = short, fragile frontal hairs


  • See also Connective Tissue Diseases:Lupus

 

II.

Lichen planopilaris (LPP)



  • Classically scarring alopecia with perifollicular scaling


  • Frontal fibrosing alopecia = appears to be a pattern of LPP, mostly in postmenopausal women


  • Graham-Little-Piccardi-Lasseur Syndrome = LPP, KP, axillary/genital non-scarring alopecia


  • Recent interest in treating LPP with pioglitazone (a TZD medication) that is a PPAR-γ agonist. PPAR- γ’s activation may help prevent scarring alopecia


  • See also Papulosquamous:Lichenoid:Lichen Planus

 

III.

Central centrifugal cicatricial alopecia (CCCA)



  • Aka follicular degeneration syndrome


  • Aka “Hot comb” alopecia


  • Classically associated with history of chemical treatments, relaxing, perms, hot combs, although no strong evidence to support these associations

 

 

(b)

Neutrophilic scarring alopecia

I.

Folliculitis decalvans



  • Flat and boggy plaques of alopecia, can become pseudopelade


  • Usually treat with antibiotics, steroids


  • Some may use term almost interchangeably with dissecting cellulitis

 

II.

Dissecting cellulitis



  • Aka perifolliculitis capitis abscedens et suffodiens


  • Terrible name: not dissecting, not a cellulitis


  • Part of the follicular occlusion tetrad, see also Acneiform Diseases


  • Clinically more separate nodules/cysts in scalp with associated alopecia, can become pseudopelade


  • Some may use term almost interchangeably with folliculitis decalvans


  • May treat with tetracyclines, isotretinoin

 

 

(c)

Mixed infiltrate scarring alopecia

I.

Acne keloidalis nuchae



  • Exact etiology unclear, but may represent a scarring reaction to ingrown hairs (pseudofolliculitis), see also Acneiform Diseases


  • Name is at least partially a misnomer – it is not caused by acne and lesions are not keloidal (on pathology), though it does classically appear on the posterior neck


  • Commonly seen in African-American patients with short curly hairs and short haircuts (which all predisposes to pseudofolliculitis)

 

 

(d)

Pseudopelade of BrocqEnd stage of scarring alopecia, tufted doll’s hairs, “footprints in the snow”

 


9.1.2 Non-Inflammatory Scarring Alopecia




(a)

Trauma

 

(b)

Traction alopecia



  • Sometimes non-inflammatory, sometimes inflammatory


  • Typically non-scarring initially, but may become scarring

 

(c)

Aplasia cutis congenita (ACC)



  • A focal congenital loss of skin/hair in newborns, may evaluate with imaging/MRI (do not want to risk biopsy)


  • “Hair collar sign” = a collar of hair seen around the skin defect


  • Ddx nevus sebaceus

    I.

    Adams-Oliver syndrome = ACC with cutis marmorata telangiectatica congenita

     

    II.

    Bart’s syndrome = ACC with epidermolysis bullosa

     

 


9.2 Non-Scarring Alopecia



9.2.1 Non-Inflammatory Non-Scarring Alopecia




(a)

Androgenic/androgenetic alopecia

Tags:
Oct 6, 2016 | Posted by in Dermatology | Comments Off on Alopecia

Full access? Get Clinical Tree
Get Clinical Tree app for offline access