Skin infections Flashcards
What is cellulitis?
Bacterial infection of the skin
What is the most common causative organism of cellulitis?
Strep. pyogenes
What can predispose people to cellulitis?
Oedema/poor circulation in the legs
How does cellulitis typically present?
- infected area is red, hot & swollen
- pyrexia
- general malaise
Investigations for cellulitis?
Bacterial swab
Management of cellulitis?
Flucloxacillin 1st line
Doxycycline if pen allergic
Vancomycin if MRSA
What is necrotising faciitis?
Life threatening soft tissue infection, basically a deeper and more serious cellulitis
Explain the pathophysiology of necrotising faciitis?
extensive tissue necrosis and toxaemia
What is the most common causative organism of necrotising faciitis?
Strep. pyogenes - around wounds/post-surgery
How does necrotising faciitis typically present?
- out of proportion pain (excruciating pain under a wound that doesn’t look that impressive)
- crepitations when skin is felt (air in skin)
- signs of infection: fever, tachycardia, hypotension
How is necrotising faciitis treated?
Immediate surgical debridement and antibiotics
What is impetigo?
V contagious superficial bacterial infection that usually affects the face in children
What is the most common cause of impetigo?
Staph aureus
How does impetigo typically present?
Red lesions with a yellow/gold crust, usually on the face
Management of impetigo?
1st line = topical fusidic acid 7 days
extensive/severe = oral flucloxacillin
What is staphylococcal scalded skin syndrome?
Blistering condition due to toxins released by certain strains of staph aureus, usually in children under 5
Explain the pathophysiology of staphylococcal scalded skin syndrome?
- Toxins from certain strains of staph aureus bind to desmosomes in the skin and break them up so that keratinocytes become unstuck
- This splits the epidermis at the granular layer and creates blisters
How does staphylococcal scalded skin syndrome typically present?
- red, blistering skin (looks like burns)
- tender & painful
- superficial epidermis peels off in sheets
Management of staphylococcal scalded skin syndrome?
IV flucloxacillin
Supportive treatment - fluid & electrolyte balance & pain relief
What is ringworm?
A fungal (dermatophyte) infection of the skin
What is the most common causative organism for ringworm and what type of transmission is it passed on by?
Trichophyton rubrum
Human-human transmission
What are the 2nd and 3rd most common causative organisms for ringworm and what type of transmission are they passed on by?
2nd = trichophyton mentagraphytes (human-human) 3rd = microsporum canis (cats/dogs-human)
What is tinea capitis?
Ringworm in the scalp