Dermatology: Skin Infections

Question 1

What are the 3 layers of the skin from top to bottom

Answer 1

epidermis
dermis
hypodermis

Question 2

What is the function of the skin?

Answer 2

Provides an anatomical barrier
Main method of Heat Regulation
Sensory input from the body
Storage for lipids and water
Drug absorption
waste excretion

Question 3

What is commensal flora

Answer 3

• normal colonisation that inhabits pathogens in healthy hosts
• mainly bacteria and fungi (staphylocci and candida)

Question 4

What is oily skin?

Answer 4

• more secretion from sebaceous glands (sebum)
• more bacterial colonisation
• skin becomes heavier and thicker
• more risk of pore blockage = more spots and pimples
• less likely to wrinkle and age

Question 5

What are comedones?

Answer 5

• blackheads
• feature of acne vulgaris
• build up of keratin and sebum
• block pores and oxidise giving ‘black’ appearance

Question 6

give 4 examples of bacterial infections of the skin

Answer 6

• furuncles and carbuncles
• acne
• erysipelas
• impetigo

Question 7

What is furuncles

Answer 7

infection of the skin- pockets with pus

• caused by staphylococcus aureus
• red, painful and swollen
• drain pus- antibiotics not always necessary

Question 8

what are carbuncles

Answer 8

furuncles grouped together

Question 9

what is folliculitis

Answer 9

furuncle in a hair follicle

Question 10

Acne is a term used for lesions arising from…

Answer 10

• comedones
• papules
• pustules
• nodules
• inflammatory cysts

Question 11

What age does acne usually affect ?

Answer 11

13-18

• 80% of teenagers

25-40

• 5% women and 1% men continue to be troubled

Question 12

What are some causes of acne?

Answer 12

• follicular sensitivity to testosterone (increase during puberty)
• propionibacterium acnes overgrows and leads to infection and cysts
• scars can form if cysts rupture

Question 13

What can acne be made worse by?

Answer 13

• some contraceptive pills (progestogen)
• greasy skin cleansers
• systemic steroid treatment
• some anticonvulsant drugs

SQUEEZING the spots

Question 14

How can acne be managed locally?

Answer 14

• reduce excess skin oil (cleaners- gentle soap)
• antibacterial agents

benzoyl peroxide
retinoids
antibiotic lotions

Question 15

How can acne be treated if local treatments fail?

Answer 15

• antibiotics (tetracycline based) minocyclin
• retinoids - isotretinoin
• hormone manipulation (anti-androgens) cyproterone

Question 16

What causes erysipelas?

Answer 16

streptoccus pyogenes

Question 17

Describe how erysipelas may present?

Answer 17

defined sharp raised border
may blister and peel
usually systemic symptoms (fever and rigors)

Question 18

How is erysipelas managed?

Answer 18

systemic antibiotics

• oral or sometimes IV

Question 19

What can erysipelas sometimes progress to>

Answer 19

necrotising fasciitis

septic shock

Question 20

What is impetigo? (causes, appearance, treatment ?)

Answer 20

• highly infectious skin disease
• staphylococcal or streptococcal
• crusty red blister appearance (often associated with eczema)
• treatment with topical antibiotics

Question 21

What are some examples of viral skin infections?

Answer 21

• herpes simplex
• shingles
• molluscum contagiosum
• warts
• measles
• rubella
• fifth disease
• roseola
• hand, foot and mouth
• HIV
• Kaposi’s Sarcoma

Question 22

What are the different types of herpes virus infections?

Answer 22

• herpes simplex (perioral or genital)
• shingles (herpes zoster)
• roseola (HHV6)
• kaposi’s sarcoma (HHV8)

Question 23

What do herpes simplex infections affect?

Answer 23

single dermatome or adjacent dermatomes

Question 24

How can herpes simplex infections be activated?

Answer 24

Trauma

• physical
• chemical
• UV light
• ’ run down’

Question 25

How can herpes simplex infections be treated?

Answer 25

Aciclovir

Question 26

What is shingles (herpes zoster)

Answer 26

- caused by herpes zoster (can be recurrent) - affects single dermatome - causes significant pain (neural inflammation from virus in the nerve) - pain may persist after rash has gone (post herpetic neuralgia)

Question 27

How is shingles treated>

Answer 27

HIGH dose aciclovir

Question 28

What causes Molluscum COntagiosum?

Answer 28

caused by MCV - a pox virus

Question 29

When does Molluscum Contagiosum usually resolve?

Answer 29

spontaneously in 1-2 years

Question 30

Who is usually affected by Molluscum Contagiosum?

Answer 30

usually infants and small children more troublesome in children with atopic eczema extensive in adults if HIV infection

Question 31

How does Molluscum Contagiosum present?

Answer 31

clusters of small papules -warm, moist areas - 1-6mm size

Question 32

What are warts?

Answer 32

Caused by human papilloma virus (HPV) - types 1-3 - spread by contact - if immune competent then most resolve spontaneously

Question 33

How do you treat warts?

Answer 33

- keratolysis - cryosurgery - excision

Question 34

Name 5 types of fungal skin infections

Answer 34

- athletes foot - nail infections - ringworm - intertrigo - pityriasis versicolor

Question 35

What is athletes foot?

Answer 35

- between toes (sometimes groin involvement) - mixed fungal and bacterial infection - scaling/ sogginess of skin

Question 36

How do you prevent athletes foot

Answer 36

keeping skin clean dry and damage free

Question 37

How do you treat athletes foot?

Answer 37

antifungal/antibacterial cream - miconazole

Question 38

What is onycholysis?

Answer 38

nail bed fungal infection usually tinea unguium infection nail becomes malformed, thick and crumbly may be seen with athletes foot

Question 39

What areas of the body can ringworm affect ?

Answer 39

- groin - tinea cruris (often spread from feet) - body - tinea corporis (can be caught from infected animals) - scalp- tinea capitis (inflammation of scalp leading to hair loss, mainly in young children)

Question 40

What causes intertrigo?

Answer 40

fungal infection due to chafing in moist body folds

Question 41

where is intertrigo most common?

Answer 41

- under breasts - armpits - inner thighs

Question 42

How do you treat intertrigo>

Answer 42

treat with topical antifungal cream - clotrimazole - miconazole

Question 43

What is pityriasis versicolor?

Answer 43

- caused by pityrosporum orbiculare (usually harmless commensal, involved in cradle cap) - presents with patchy skin pigmentation (pale red or brown)

Question 44

how do you treat pityriasis versicolor?

Answer 44

- with topical or systemic antifungal topical ketoconazole (in wash or shampoo) - systemic itraconazole

Question 45

Name 2 skin infestations?

Answer 45

- scabies - lice

Question 46

What are scabies?

Answer 46

- infection by the scabies mite - contracted by skin-to-skin contact - mites borrow into skin between fingers and on wrists -presents with red “burrows” on skin, itch and rash that can appear on trunk and legs -can develop into secondary impetigo

Question 47

How do you treat scabies>

Answer 47

- use chemical insecticides - scabicides benzyl benzoate permethrin malathion - apply to whole body from the chin down including under the nails

Question 48

Name three types of lice

Answer 48

head pubic body

Question 49

How is lice transmitted

Answer 49

close contact with an infected individual shared items (clothing combs, bedding, brushed and toilet seats)

Question 50

How is lice treated?

Answer 50

looks for 'nits' - eggs cemented to the hair near the scalp - need to go through hair with a find toothed comb NOT hygiene related -body lice treated by personal and clothing hygiene (hot water washing and drying) - chemical insecticides (permethrin, malathion, phenothrin)