adnexal structures and disorders

Question 1

Pilosebaceous unit

Answer 1

from inner to outer:

Bulb, isthmus, infundibulum, shaft

Question 2

Types of pilosebaceous units\

Answer 2

3 types
Lanugo (fetal)
Vellus (fine)
Terminal (Coarse)

Abnormal hair type for age or location may herald an underlying condition: Anorexia (lanugo), Hirsutism (Terminal, beard due to PCOS)

Question 3

Sebaceous glands

Answer 3

Greates density on face and scalp, but everywhere

Produce sebum (oils- Triglycerides, free fatty acids, squalene, wax and sterol esters, and free sterols)

Occurs thru holocrine secretion (aka bursting cells)

Active at birth but decreases during infancy (Sebum production stimulated by androgen production 5-aDHT in puberty

Question 4

Hair Cycle

Answer 4

Ana’s Cat Tells us meow

Growth phase: Anagen (majority of scalp is in anagen, duration dictates hair length)

Transition phase: catagen

Resting phase: telogen (hair sheds during this process)

Question 5

Telogen effluvium

Answer 5

” telogen forever”

Stressor results in greater proportion of hair follicles entering Telogen phase

Results in increase amount of hair being shed, occurs approximately 3 months after event slowly returns to normal

Question 6

Alopecia areata

Answer 6

autoimmune condition
Smooth patches of complete allopecia develop, nail pits may be seen, topical corticosteroids are the mainstay of treatment

Question 7

Innervation of eccrine glands

Answer 7

post ganglionic sympathetic fibers with acetylcholine as the principal neurotransmitter

Question 8

Sweat glands

Answer 8

eccrine (sweaty): palms and soles, innervated by sympathetic fibers via acetylcholine-by itself

apocrine (Sweaty and stinky): axillae, anogenital, periumbilical, areolae, vermilion border, eyelid (Molls)- in the hair follicle

Question 9

Acne

Answer 9

Propionibacterium acnes

anaerobic gram positive rod
Dependent on glycerol (hydrolysis of sebum triglycerides)
Produce: Porphyrins, proinflammatory mediators, lipases

Question 10

Systemic treatments of acne

Answer 10

antibiotics, oral contraceptives, spironolactone, isotretinoin

Question 11

Antibiotics

Answer 11

first line choice : tetracyclines (doxycycline)

others:erythromycin, TMP-SMX, penicillins

MOA: inhibits p acnes, antiinflammatory

SE: Doxy: pill esophagitis, photosensitivity
Mino:drug hypersensitivity syndrome, drug induced lupus, hepatitis

Question 12

Oral contraceptives

Answer 12

MOA: block production of androgens (adrenal and ovarian), increased sex hormone binding globulin=decreased free testosterone

Type of acne: inflammatory papules/pustules, perimenstrual flare

SE: Nausea, vomiting, abnral menses, wt gain, breast tenderness, thrombophlebitis, HTN

Question 13

Spironolactone

Answer 13

Potassium sparig diuretic
Used for HTN and HF

can be used for hormonal acne(anti androgen effects) inflammatory papules and pustules, perimenstrual flares

SE: Breast tenderness, menstrual cramping, spotting

Best result when combineed with OCP

Question 14

Isotretinoin

Answer 14

indicated for severe nodulocystic acne, scarring, sever acne recalcitrant to systemic antibiotic therapy and topicals

dose: cumulative: 120-150 mg/kg

1mg/kg/day divided BID x 5 months

Question 15

Tinea versicolor

Answer 15

Malassezia spp (globosa and furfur)
Oval to round scaly patchers with fine overlying scale

Hyperpigmented or hypopigmented