Skin function and terminology

Question 1

Functions of the skin

Answer 1

Immunological barrier
Temperature regulation
Element/UV protection
Sensory and endocrine function

Question 2

Skin structure

Answer 2

Stratum corneum
Epidermis
Dermis
Subcutaneous layer

Question 3

Macule

Answer 3

A change in surface colour without elevation or depression (nonpalpable)
5-10mm
If there is some minor surface changes it is a ‘patch’

Question 4

Papule

Answer 4

A circumscribed, solid elevation of the skin with no visible fluid
5-10mm

Question 5

Nodule

Answer 5

A large papule >1cm, situated in the dermis or subcutaneous tissue
Differentiated from a papule by size and depth

Question 6

Plaque

Answer 6

Can be a large papule or the confluence of papules
>1cm
May produce a plateau-like lesion where diameter is greater than depth

Question 7

Vesicle

Answer 7

Bulla if large

A circumscribed, fluid containing epidermal elevation up to 5-10mm

Question 8

Lichenification

Answer 8

Epidermal thickening with visible and palpable thickening of the skin with accentuated skin markings

Question 9

Erosion

Answer 9

A discontinuity of the skin with incomplete loss of the epidermis. Generally moist and depressed

Question 10

Ulcer

Answer 10

A discontinuity of the skin with complete loss of the epidermis and maybe the dermis and deeper structures.

Question 11

Erythema

Answer 11

Redness due to hyperemia of capillaries

Question 12

Pustule

Answer 12

A small skin elevation containing cloudy or purulent material made of necrotic inflammatory cells - may be white or red

Question 13

Wheal

Answer 13

A rounded or flat topped pale red papule which is usually transient

Question 14

Scaling

Answer 14

Dry or greasy laminated masses of keratin from the thickened stratum corneum

Question 15

Desquamation

Answer 15

The collective shedding of sheets of thickened stratum corneum

Question 16

Xerosis

Answer 16

Abnormal dryness of the skin or mucus membranes

Question 17

Target Lesions

Answer 17

Typical lesion of erythema multiforme (EM)

Consists of dark, central papule/vesicle, pale intermediate zone and peripheral ring of erythema

Question 18

Factors effecting skin function

Answer 18

Genetics, Body site, Irritants and detergent use
Proteases – inflammatory cells, house dust mites, Staph A
Corticosteroid use

Question 19

Allergy testing

Answer 19

Skin prick test – Food allergies and pollen
Skin Patch test – contact dermatitis and irritants. takes 4 days
Radioallergosorbent test (RAST) – used for food allergies, inhaled allergens and wasp/bee venom. determines the amount of IgE and can be used when skin tests are not suitable (extensive eczema or anti-histamine use).

Question 20

Hirsutism

Answer 20

Androgen dependent
Most commonly PCOS, also cushings, congenital adrenal hyperplasia, androgen therapy, obesity, phenytoin
Assessed by Ferriman-Gallwey scoring system (>15 is moderate or severe). Treat with weight loss or COC. Can use topical eflornithine (except in pregnancy or breastfeeding)

Question 21

Hypertrichosis

Answer 21

Androgen independent
Minoxidil, ciclosporin and Diazoxide
Can be due to Congenital hypertrichosis lanuginosa or terminalis.
Porphyria cutanea tarda or anorexia nervosis.