Skin infections

Question 1

Fungal infections: Overview

Answer 1

Superficial mycoses are the commonest of human fungal infections and are limited to skin, hair, nails and mucous membranes.

Spread is from:

• Human to human
• Animal to human
• Soil to human

Question 2

RINGworm infection: Definition

Answer 2

Round, scaly itchy lesion whose edge is more inflamed than it’s centre. It is called tinea followed, in latin, by the part affected.

Example: tinea pedis (foot)

Infection caused by yeasts of Candida genus (e.g. C Albicans) are common and mostly affect the mouth, vagina, glans, skin folds, toe web and nail areas.

Diagnosis: skin scrapings, microscopy + culture, skin swabs

Question 3

BACTERIAL infections of the SKIN

Answer 3

• Impetigo
• Erysipelas
• Cellulitis
• Skin TB

Question 4

Cellulitis: Definition

Answer 4

Cellulitis is an infection of the skin and the soft tissues underneath.

The skin normally acts as a very effective physical barrier between the environment and soft tissues.

When a patient presents with cellulitis look for a breach in the skin barrier and a point of entry for the bacteria. This may be due to skin trauma, eczematous skin, fungal nail infections or ulcers.

Question 5

Cellulitis: Presentation

Answer 5

The skin will demonstrate changes:

• Erythema (red discolouration)
• Warm or hot to touch
• Tense
• Thickened
• Oedematous
• Bullae (fluid filled blisters)
• A golden-yellow crust can be present and indicate a staphylococcus aureus infection

Question 6

Cellulitis: Causes

Answer 6

The most common causes are:

• Staphylococcus aureus
• Group A Streptococcus (mainly streptococcus pyogenes)
• Group C Streptococcus (mainly Streptococcus dysgalactiae)

Other causes

• MRSA

Question 7

Cellulitis: ERON classification

Answer 7

This is the classification system NICE recommends for the assessment of the severity of cellulitis:

Class 1 – no systemic toxicity or comorbidity
Class 2 – systemic toxicity or comorbidity
Class 3 – significant systemic toxicity or significant comorbidity
Class 4 – sepsis or life threatening
Admit the patient for intravenous antibiotics if they are class 3 or 4. Also consider admission for frail, very young or immunocompromised patients.

Question 8

Cellulitis: Antibiotics

Answer 8

Flucloxacillin is very effective against staph infections and also works well against other gram positive cocci. It is usually the first choice in treating cellulitis and can be given oral or intravenous.

Alternatives:

• Clarithromycin
• Clindamycin
• Co-amoxiclav

Question 9

Common VIRAL skin infections

Answer 9

• Warts
• Molluscum contagiosum
• Herpes simplex
• Herpes zoster