Alopecias Flashcards
Two major types of alopecia?
Scarring and non-scarring
What do you look for to see if an alopecia is inflammatory vs not?
Look to see if the ostia is present or not
Difference between male and female androgenic alopecia?
Male pattern: Starts at the temporal area and reshapes anterior hairline
Women: Diffuse thinning on crown, less temporal recession and the frontal hairline is maintained. Has a more Christmas tree shape to loss.
Histology of androgen-dependent alopecia?
Increased vellus hairs (diameter of the hair shaft < inner root sheath width), mildly increased telogen to anagen ratio (follicles will be higher in the dermis, anagen should be near subcutis).
- In final stage connective tissue can replace follicular structure (scarring)
Treatment for androgen-dependent alopecia?
- minoxidil 2 or 5%
- finasteride
- dutasteride (both 5-ɑ reductase isoforms) [some stuff suggesting this may be more effective]
- hair transplant
At what stage in the hair cycle is the bulb lowest in the dermis?
Mature anagen, most shallow during telogen
Two major types of alopecia?
Scarring and non-scarring
Major types of scarring alopecia?
DLE, Morphea, Infections/Tinea capitis, Radiation, Burn, Lichen planopilaris
Major types of non-scarring alopecia?
Alopecia areata, androgenitic alopecia, telogen effluvium, trichotillomania, traction alopecia
What are the two main divisions of alopecias within the non-inflammatory category?
Normal follicle number and decreased follicle number
What are the types of alopecia associated with non-inflammatory processes that have normal follicle numbers?
Androgenetic alopecia, telogen effluvium, trichotillomania
What are the types of alopecia associated with non-inflammatory processes that have decreased follicle numbers?
Traction alopecia
How are the inflammatory alopecias divided?
They can be divided by cell type: lymphocytic, neutrophilic, histiocytic/plasma cells, and little or no inflammation
What are the major lymphocyte driven inflammatory alopecias?
Discoid lupus erythematosus, alopecia areata, lichen planopilaris
What are the major neutrophil driven inflammatory alopecias?
Folliculitis decalvans, tinea capitis, zoster, dissecting cellulitis, burns, radiation
What are the major Histiocytes and Plasma Cells driven inflammatory alopecias?
Secondary Syphilis
What inflammatory alopecias have little or no inflammation?
alopecia areata, late lichen planopilaris, late discoid lupus, late scleroderma, late burn, radiation associated
Epidemiology of androgenetic alopecia?
M>>F (80% caucasian men affected by age 70). The incidence in women increases after menopause.
Groups with the lowest rates of androgenetic alopecia?
Native Americans and Eskimos
Genetics of androgenetic alopecia?
Both polygenic and autosomal dominant
What is the hormone that drives androgenetic alopecia?
DHT… it is an androgen-dependent process. If men are castrated before puberty no androgenetic alopecia occurs.
What is the pattern seen with male androgenetic alopecia?
Starts at the temporal area, reshapes the anterior hairline
What is the pattern seen with female androgenetic alopecia?
Diffuse thinning on the crown, less temporal recession and the frontal hairline is maintained
What is the workup for androgenetic alopecia in women?
Evidence of hirsutism/PCOS/virilization: check DHEA-S, total and free testosterone, prolactin
What is the workup for androgenetic alopecia in both men and women?
TSH, debatably ferritin, consider telogen effluvium which can lead to an accelerated rate of pattern alopecia
Histopathology of androgenetic alopecia?
- increased vellus hairs
- mildly increased telogen to anagen ratio
- in final stage, connective tissue can replace follicular structure (scarring)
Treatment for androgenetic alopecia?
- minoxidil 2 or 5%
- finasteride
- dutasteride (both 5-ɑ reductase isoforms)
- hair transplant
On histology, how can a vellous hair be distinguished?
In vellous hair, the hair shaft is smaller than the inner root sheath.
What is the usual timing of telogen effluvium?
Precipitating event usually 3 months prior to diffuse shedding
How does telogen effluvium present?
Reduced density of hair, hair growth usually returns after months to years
Most common causes of telogen effluvium?
- postfebrile
- severe infection
- severe chronic illness
- severe, prolonged psychological stress
- hypothyroidism / hyperparathyroidism
- malnutrition
- drugs (retinoids, stopping OCPs, heparin, antidepressants, lithium, amphetamines, antithyroid meds, anticonvulsants, β-blockers)
*some cases can be idiopathic
Most common drugs associated with telogen effluvium?
retinoids, stopping OCPs, heparin, antidepressants, lithium, amphetamines, antithyroid meds, anticonvulsants, β-blockers
What is alopecia areata?
Autoimmune disease with increased CD8+ T-cells in the hair matrix → surround the hair bulb in deep dermis
What type of T-cells drive alopecia areata?
CD8+ t-cells
What other conditions is alopecia areata associated with?
Atopy, Hashimoto’s thyroiditis, vitiligo, IBD
What signaling molecules are key in alopecia areata?
IL-15 and IFN-gamma
How do JAK-inhibitors work in alopecia areata?
They break the IFN-gamma signalling
What are the clinical varients of alopecia areata?
Alopecia totalis (loss of total scalp hair), or universalis (loss of all hair), or ophiasis pattern (band-like pattern of loss along temporal/occipital scalp).
What pattern of alopecia areata is resistant to treatment?
Ophiasis pattern
What types of hair can be seen at the borders of alopecia areata lesions?
Exclamation point hairs. These are wider at the top than at the bottom
What physical exam findings can be found in alopecia areata?
exclamation point hairs at borders of lesions, regular nail pitting, trachyonychia
Treatment options for alopecia areata?
intralesional kenalog (5mg/mL), topical irritants (anthralin, tazarotene), JAK inhibitors in the future For rapidly progressive disease –> oral CS pulsed over 2-3 months
What is trichotillomania?
Self-induced hair loss from twirling, pulling and or breaking the hair
*Often underlying psychological stressor or disorder
Exam findings suggestive of trichotillomania?
Hair tends to be of different length, occiput often spared, can do the clipped hair test where the hair is clipped short and the regrowth can be observed before it is long enough to pull
Treatment for trichotillomania?
Behavioral modification is the primary modality. SSRI second line and clomipramine in children and adolescents.
What is pressure-induced alopecia
Most commonly after very long surgical procedures. Most common resulting location is the occiput (solitary, oval patch)
Histopathology in trichotillomania?
Look for tracheomalacia which is deformed hair shafts
What chemo drugs are associated with anagen effluvium?
cyclophosphamide, doxorubicin, paclitaxel, etoposide
What is anagen effluvium?
You get loss of growth phase hairs… so the hairs remain short before being shed.
What pattern is seen in alopecia secondary to secondary syphilis?
Moth-eaten alopecia and telogen effluvium
Where is central centrifugal cicatricial alopecia seen most commonly?
Black women 2/2 use of chemical hair relaxers or flat iron
Presentation of central centrifugal cicatricial alopecia?
progressive scarring alopecia centered on the crown and midline. Usually asymptomatic but sometimes a secondary change of crusting or pustules can occur
Treatment of central centrifugal cicatricial alopecia?
-oral tetracyclines plus potent topical steroids -severe disease - oral rifampin plus clindamycin -if perifollicular erythema present - ILK -change or decrease the use of chemical hair products
Epidemiology of lichen planopilaris?
Affects W>>M, 50% have associated LP of the skin, mucous membranes, or nails
Clinical presentation of lichen planopilaris?
- clinically, p/w several foci of alopecia with loss of follicles and scarring centrally. Look for perifollicular erythema or scale
- m/c locations: crown/vertex or midline vs frontal hairline and eyebrows (frontal fibrosing alopecia)
- perifollicular erythema to violaceous color signify inflammation
Most common areas for lichen planopilaris?
crown/vertex or midline vs frontal hairline and eyebrows (frontal fibrosing alopecia)
What is Graham-Little syndrome?
Scarring scalp alopecia, alopecia of axillary/pubic areas that is not scarring and grouped spinous follicular papules on trunk/extremities
Treatment for lichen planopilaris?
- oral antimalarials
- topical or ILK
- oral doxycycline
- MMF for severe or recalcitrant cases
Clinical presentation of discoid lupus erythematosus?
- clinically p/w circular lesions of erythema, atrophy, dilated/plugged follicles with scale and alopecia
- later stage shows central hypopigmentation and peripheral hyperpigmentation + scarring
Treatment for discoid lupus erythematosus?
anti-malarials
Key distinguisher of discoid lupus erythematosus vs lichen planopilaris on histology?
Discoid lupus affects the acrosyringium whereas lichen planopilaris does not.
What is the occlusion tetrad?
Dissecting cellulitis, acne conglobata, HS, pilonidal cysts/sinus
How does dissecting cellulitis present?
Multiple, firm, scalp nodules over crown and occiput → boggy and fluctuant with purulent discharge with interconnections
+/- pain
Treatment for dissecting cellulitis?
- ILK
- abx based on cx
- incision and drainage
- excision
What is folliculitis decalvans?
Inflammatory scarring alopecia with perifollicular papules and pustules
Presentation for folliculitis decalvans?
Recurrent crops of epilating follicular pustules
Treatment for folliculitis decalvans?
Dapsone (neutrophil driven process), tetracyclines
What is pseudopelade?
This is the end-stage or burned out stage of different types of scarring alopecias.
Most common etiology of pseudopelade?
End-stage lichen planopilaris
What is the histology of pseudopelade?
Shrunken, deep red dermis - fibrous tract remnants - thickened elastic fibers in dermis
What is traction alopecia?
It is seen after years of hairstyling that causes excessive traction.
Essentially a scarring alopecia that can resemble trichotillomania early on but progresses usually from anterior hairline and moves towards the vertex
What are poor prognostic indicators for alopecia areata?
the severity of onset, ophiasis pattern, younger age of onset; diffuse-type has good prognosis; m/c a/w vitiligo
Most commonly associated diseases with alopecia areata?
Vitiligo
What must patients be warned of prior to starting minoxidil?
Immediate release of telogen hair… more hair will fall out initially
Important side effects of finasteride?
Change in the prostate (ejaculate volume), depression, decreased libido, erection problems, increased risk of HIGH-grade prostate cancer
What are the two primary types of 5-a reductase and where are they located?
type I mainly on the scalp, sebaceous glands, and liver type II mainly in prostate and liver
What things are related to DHT levels?
Growth of beard, prostate, acne at puberty, and temporal hair recession
What 5-a reductase subtypes does finasteride block?
Finasteride blocks just the type II 5a reductase
What 5a reductase subtypes does the dutasteride block?
Dutasteride blocks both the type I and the type II
