Adnexal Structures and Associated Disorders

Question 1

Layers of pilosebaceous unit:

Answer 1

1. Infundibulum (skin surface –> sebaceous gland)
2. Isthmus (sebaceous gland –> arrector pili muscle)
3. Inferior segment (EPM –> pilosebaceous gland)

Question 2

3 types of pilosebaceous unit:

Answer 2

1. Lanugo (fetal)
2. Vellus (fine)
3. Terminal (coarse)

Question 3

Conditions which may be heralded by abnormal presence of hair types:

Answer 3

1. Anorexia (lanugo)
2. Hirsutism (terminal; females with terminal hairs in a male pattern distribution may indicate androgen excess/polycystic ovarian syndrome (PCOS))

Question 4

Sebum:

Answer 4

• Triglycerides, FFA, squalene, wax, sterol esters, free sterols.
• Secretion stimulated by androgen production in puberty.

Question 5

Hair cycle:

Answer 5

1. Anagen (growth phase)
2. Catagen (transition phase)
3. Telogen (resting phase; hair shed during this phase)

Question 6

Telogen effluvium:

Answer 6

• Stressor results in greater production of hair follicles entering telogen phase.
• Diffuse: no patches as in alopecia areata.
• Diagnostic test: look at hair under a scope to look for telogen bulb.

Question 7

Alopecia areata:

Answer 7

• Autoimmune condition.
• Smooth PATCHES of alopecia develop. Tend to be focal.
• May see nail pits.
• Topical corticosteroids are the mainstay of treatment.

Question 8

2 types of sweat glands:

Answer 8

1. Eccrine: palms and soles. Innervated by sympathetic fibers via ACh.
2. Apocrine: axillae, anogenital, periumbilical, areolae, vermilion border of lips.

Question 9

Hyperhidrosis:

Answer 9

Excessive sweating. Annoying, but not life-threatening.

Question 10

Anhidrosis/hypohidrosis:

Answer 10

Occurs when sweat glands are absent/reduced, as in ectodermal dysplasia.

Problems with thermoregulation.

Question 11

Androgens play a role in what two components of acne production:

Answer 11

1. Secretion of sebum via sebaceous cells.

2. Proliferation of follicular keratinocytes.

Question 12

Bacterium responsible for acne:

Answer 12

Propionibacterium acnes; dependent on glycerol.

Produce: porphyrins, proinflammatory mediators, lipases.

Question 13

Retinoids:

Answer 13

Normalize follicular keratinocytes and a little anti-inflammatory.

Question 14

Benzoyl peroxide:

Answer 14

Help with killing P acnes, help a little with sebum production.

Question 15

Antibiotics:

Answer 15

Only help minimize P acnes.

Tetracyclines, erythromycin, bactrim, penicillins.

Downside: SEs. Minocycline has drug hypersensitivity syndrome. Doxy has pill esophagitis and photosensitivity.

Question 16

Oral contraceptives in the treatment of acne:

Answer 16

• Block production of androgens.
• Only works in certain kinds of acne: inflammatory papules/pustules, peri-menstrual flare.
• SEs: Hormonal stuff, nausea, vomiting, thromboembolisms.

Question 17

Isotretinoin:

Answer 17

• Used for severe acne recalcitrant to systemic antibiotic therapy and topicals.