Lecture 4: Skin Infections and Infestations

Question 1

which organsims live on our skin?

Answer 1

• aerobic cocci: staph epidermis and staph aureus
• other aerobic and anaerobic bacteria: corynebacterium, propionbacterium
• yeasts: Malassezia furfur

Question 2

what are the signs of a skin infection?

Answer 2

• erythema
• hot
• tender
• pus
• exudate
• fever

Question 3

skin infection investigations

Answer 3

• skin swab for microscopy, culture and sensitivities (M,C&S)
• if clinically indicated: FBC, ESR, U&Es, LFTs, calcium, CRP, skin biopsy

Question 4

what is the most common bacterial skin infection in children?

Answer 4

impetigo - superficial skin infection

Question 5

what is the treatment for localised and widespread impetigo?

Answer 5

If localised:
- Fusidic acid 2% cream 3-4x daily for 5 days.
- Mupirocin 2% cream up to 3x dailu for 5 days (if MRSA)

If widespread, severe, bullous:
- flucloxacillin 500mg oral 4x daily for 7 days
- erythromycin 500mg oral 4x daily for 7 days (if penicillin allergy)

Question 6

what are the first choice antibiotics to treat cellulitis/erysipelas (if severe)?

Answer 6

• flucloxacillin 1g IV every 6 hours
• plus Benzylpenicillin 1.8g IV every 6 hours

Question 7

what is the treatment for lipodermatosclerosis?

Answer 7

• treat underlying venous disease
• topical steroids

Question 8

what is tinea on the body called?

Answer 8

ringworm or tinea corporis

Question 9

what is tinea on the head called?

Answer 9

tinea capitis

Question 10

what is tinea on the foot called?

Answer 10

tinea pedis (athlete’s foot)

Question 11

what is tinea on the groin called?

Answer 11

tinea cruris

Question 12

what is tinea on the nails called?

Answer 12

onychomycosis (fungal nail)

Question 13

what is the treatment of tinea infection of feet, body, hands or groin?

Answer 13

usually responds to topical treatment such as Terbinafine or Clotrimazole cream

Question 14

what is the treatment of tinea infection of scalp or nails?

Answer 14

oral antifungals

Question 15

what is the treatment for candida infection?

Answer 15

• nystatin
• miconazole
• ketoconazole cream

Question 16

hand/finger warts are caused by which organism?

Answer 16

human papilloma virus

Question 17

what is the treatment for hand/finger warts?

Answer 17

• normally not necessary or very effective
• give patient a leaflet on viral warts
• wart paints and cryotherapy can stimulate immune system
• warts will go away when patients develop immunity against wart virus

Question 18

what causes molluscum contagiosum?

Answer 18

DNA pox virus

Question 19

molluscum contagiosum treatment

Answer 19

• will resolve when patient develops immunity
• can use 5% potassium hydroxide topical treatment

Question 20

what conditions can herpes simplex 1 and 2 virus cause?

Answer 20

• cold sore
• eczema herpeticum

Question 21

how are herpes simplex virus infections treated?

Answer 21

aciclovir

Question 22

what is the mite that causes Scabies called?

Answer 22

Sarcoptes scabiei

Question 23

which areas of the body does scabies usually affect?

Answer 23

• inter-web spaces
• flexures of the wrist
• axillae
• abdomen
• groin

Question 24

describe Norweigan (or crusted) scabies

Answer 24

• Norweigan (or crusted) scabies is where an individual is affected by millions of mites causing a generalised scaly rash.
• It is seen in immunocompromised patients e.g. those with HIV

Question 25

scabies investigations

Answer 25

• clinical exam
• skin scraping
• skin biopsy

Question 26

what is the treatment for scabies?

Answer 26

• permethrin cream top to toe for 8 hours, two apllications, 30g, 1 week apart
• treat all in household and close contacts
• explain itch may take 1-4 weeks to settle: treat symptomatically with steroid