Skin Infections and Infestations Flashcards
Skin Infections: types
Bacterial
Fungal
Viral
What lives on our skin
Aerobic cocci Staphylococcus epidermidis (1)++ Staphylococcus aureus* (2)+ Other aerobic and anaerobic bacteria Corynebacterium Propionbacterium Yeasts Malassezia furfur
signs of an infection:
Erythema Hot Tender Pus Exudate Fever
Signs its not an infection:
- No systemic symptoms
- Rash is not hot, tender and there is no exudate
- Atopic eczema
Other clues:
* Patient was apyrexial, no rigors *
** Long history of a relapsing rash **
* No growth of pathogens on skin swab *
Not everything which is purulent is an infection
Skin infection Investigations - Bacterial
Skin swab for Microscopy, culture and sensitivities (M,C&S)
If clinically indicated:
Full blood count, ESR
U&Es, LFTs, Calcium, CRP
Skin biopsy
Swab – Staphylococcus aureus
blue - cocci (diplo)
Most Common Bacterial Skin infection:
Impetigo
Impetigo
Impetigo – superficial skin infection
It is the most common bacterial skin infection in children
Scabs around face/mouth
Can be bullous
Staphylococcus aureus, Streptococcus pyogenes
Impetigo Causative Agents
Staphylococcus aureus, Streptococcus pyogenes
Impetigo - treatment
IF LOCALISED
Always check local formulary
If localised:
Fusidic acid 2% cream 3-4 times daily for 5 days
Mupirocin 2% cream up to 3 times daily for 5 days (if MRSA)
Impetigo - treatment
IF WIDESPREAD, SEVERE, BULLOUS
If widespread, severe, bullous:
Flucloxacillin 500mg oral four times daily for 7 days
Erythromycin 500mg oral four times daily for 7 days
Cellulitis/Erysipelas BOTH PRESENT AS:
ERYTHEMA
Cellulitis/Erysipelas Causative organisms
Cellulitis/Erysipelas
Likely organism
Streptococcus pyogenes,
Staphylococcus aureus
Cellulitis/Erysipelas Treatment - 1st Choice
1st choice antibiotic (if severe)
Flucloxacillin 1g IV every 6 hours
plus Benzylpenicillin 1.8g IV every 6 hours
Differential diagnosis
Erythema/Bullae
Deep vein thrombosis
Venous eczema
Allergic contact dermatitis
Necrotising fasciitis
Bacterial Infection Management
Take swab Start antibiotics Review after ~48hrs check skin swab result switch according to sensitivities If not better in a week: consider alternative diagnosis
Tense Bullae, Blisters and Swelling - non-infective cause:
Oedema blisters
Oedema blisters:
Acute exacerbation of oedema
Dorsum of feet
Often erythematous
Can feel hot
Non-infective venous disease often misdiagnosed as cellulitis
Lipodermatosclerosis
Lipodermatosclerosis
If acute can be hot and tender look for signs of venous disease bilateral (often misdiagnosed as cellulitis) treatment: treat underlying venous disease topical steroids
Fungal infections
Tinea
Infection by a Dermatophyte
Candidiasis
ROUND - RED RINGS
Tinea
Name depends on site affected Ringworm or Tinea corporis if on body Tinea capitis if on head Tinea pedis (Athlete’s foot) Tinea cruris affects the groin Onychomycosis affects the nails
Tinea capitis
head
Ringworm or Tinea corporis
Body
Tinea pedis
Feet (Athlete’s foot)
