Section 31- Hair Follicles Flashcards
Growth phase of hair follicle
Determines ultimate length of hair at site
Anagen
Degenerative phase of hair follicle
Apoptosis driven
1% of hair in this phase
Catagen
Period of relative quiescence stage in hair follicle
Telogen
Active process of hair shaft shedding
Exogen
Fine, non pigmented hair
Growth not affected by hormones
Vellus hair
Thick pigmented hair
Growth affected by hormones
Terminal hair
Lab exam for hair that determines the number of anagen and telogen hairs
Trichogram
Most common type of progressive balding
Pattern Hair Loss
Androgenetic alopecia
This hormone causes growth of prostate, terminal hair, AGA and acne
Dihydrotestosterone
This hormone causes growth of axillary hair and lower pubic hair
Sex drive, spermatogenesis, growth of scrotum and phallus
Testosterone
Testosterone is converted to DHT by this enzyme
5a- reductase
Men usually exhibit pattern hair loss in these sites:
Frontotemporal
Vertex
Hormone studies in women with hair loss and evidence of increased androgens
Testosterone- free and total
DHEAS
Prolactin
Others: TSH FT4 serum iron CBC ANA
Management for pattern hair loss
Oral finasteride 1mg/ day
Topical minoxidil 2% and 5%
Antiandrogens - spironolactone cimetidine flutamide
Topical latanoprost 0.1%
A localized loss of hair in round or oval areas with no apparent inflammation of the skin
Alopecia areata
Associated conditions in alopecia areata
Autoimmune thyroiditis
Down syndrome
Type of alopecia areata where there is total loss of terminal scalp hair
Alopecia areata totalis
Type of alopecia areata where there is total loss of terminal scalp and body hair
Alopecia areata universalis
Type of alopecia areata where there is bandlike pattern of hair loss over periphery of scalp
Ophiasis
Transient increased shedding of normal club hair (telogen) from resting scalp follicles
Accelerated shift of anagen into catagen and telogen
Telogen effluvium
Second most common cause of alopecia after AGA
Telogen effluvium
Individuals with telogen effluvium may also affect the growth of nails and can result to this nail condition
Beau lines
Nail findings in alopecia areata
Fine pitting (“hammered brass”) of dorsal nail plate
Lab exams to rule out other causes of hair loss
Serum iron Iron binding capacity TSH, FT4 ANA (rule out SLE) RPR (rule out secondary syphilis)
Anagen cycle disrupted
Scalp hair loss diffuse and extensive
Due to radiation therapy, chemotherapy with alkylating agents, mercury thallium boric acid intoxications or severe protein malnutrition
Regrows after discontinuation
Anagen effluvium
Results from damage or destruction of hair follicle stem cells by inflammatory, infection and other pathologic processes
Cicatricial or scarring alopecia
Effacement of follicular orifices in a patchy or focal distribution
Replacement of the follicular structure by fibrous tissue
Cicatricial or scarring alopecia
[scarring alopecia]
Perifollicular erythema +/- hyperkeratosis
Violaceous discoloration of the scalp
Results in permanent hair loss, most common in parietal scalp
May or may not be associated with lichen planus of skin/mucosa
Lichen planopilaris
Variant of lichen planopilaris where there is LP like lesions with follicular spines in areas of alopecia on scalp, eyebrows, axilla and pubic areas
Graham-Little Syndrome
Variant of lichen planopilaris where there is frontotemporal hairline recession and eyebrow loss in postmenopausal women with perifollicular erythema
Frontal fibrosing alopecia
End stage of all non inflammatory scarring alopecias
Early moth-eaten pattern with eventual coalescence into larger patches of hair loss( footprints in the snow)
Pseudopelade of Brocq
Type of alopecia in relation to chemical processing, heat or chronic tension on the hair
Most common in black women
Begins in crown/midvertex and advances centrifugally
Central centrifugal scarring alopecia
Hot comb alopecia
Type of scarring alopecia that may be a symptom of cutaneous T cell lymphoma
Alopecia mucinosa
[scarring alopecia]
Pustular folliculitis
Surviving hairs clustered (tufted folliculitis)
Bogginess or induration with pustules, erosions or crusts
S.aureus infection common
Folliculitis Decalvans
[scarring alopecia]
Most common in black men
Initial deep inflammatory nodules over the occciput
Sinus tracts may form
S aureus secondary infection common
Dissecting folliculitis
[scarring alopecia] Most commonly in black men Occurs in occipital scalp and nape Chronic papular or pustular eruption Keloidal scar may occur
Folliculitis keloidalis nuchae
[scarring alopecia]
Commonly called razor bumps
Related to curved hair follicles that retract beneath skin surface, grow and cause a foreign body reaction
S aureus secondary infection common
Pseudofolliculitis barbae
[scarring alopecia]
Painful or pruritic erythematous follicular based papule with central necrosis, crusting and healing with depressed scar
Acne necrotica
Treatment for scarring alopecia
Topical high potency and intralesional glucocorticoids-mainstay of treatment
Antibiotics- for S.aureus infection
Excessive hair growth secondary to increased androgenic activity
Hirsutism
Hair density or length beyond accepted limits of normal age, race and sex
Hypertrichosis
Hormonal stimulus for hair growth
Dihydrotestosterone
In evaluating hirsutism, if serum testosterone is more than ___ ng/ml, exclude androgen secreting tumor
> 200ng/ml
If serum testosterone and DHEA are more than ___ug/d, it is suggestive of adrenal tumor
> 800 ug/d
Raised levels of this hormone suggests CAH
17-hydroxyprogesterone
Drugs that can cause hypertrichosis
Minoxidil Phenytoin Cyclosporine Glucocorticoids Streptomycin PUVA
