Skin and soft tissue infections Flashcards
What are some routes of infection?
- Skin - pores, hair follicles
- Wounds - scratches, cuts, burns
- Bites - insects, animals
What are the three main layers of the skin?
- Epidermis
- Dermis
- Hypodermis
What should be included in the history of a patient when investigating a skin infection?
- The onset, evolution, duration and location of lesions
- Contacts with a similar rash
- Past medical history noting skin conditions such as eczema or immunosuppression
- Skin trauma or abrasions or bites
- Previous treatment including antimicrobial therapy
- Systemic features such as fever
How is cellulitis managed in primary care?
- Class I cellulitis - draw a line around the lesion, prescribe high-dose oral antibiotics according to local guidelines
- Pain relief and elevation
- Deal with concomitant skin lesions
- Provide patient information on cellulitis
- Refer patients with recurrent cellulitis
- Review in 48 hours
When is referral needed when managing cellulitis?
- Part of an outbreak
- Diagnostic uncertainty
- Resistant to maximal treatment
- Complications
What hygiene measures would you advise to aid healing and prevent spreading of a skin disease?
- Wash affected areas with soap and water
- Wash their hands regularly, in particular after touching a patch of impetigo
- Avoid scratching affected areas
- Avoid sharing towels
What skin layer do different infections affect?
- Impetigo - epidermis
- Erysipelas - epidermis and upper dermis
- Cellulitis - dermis and lower epidermis
- Necrotising fasciitis - all bar the top part of epidermis
What are some fungi that can cause skin infections?
Dermatophytes
- tinea spp
- e.g tinea pedis
- e.g tinea corporis
- e.g tine cruris
Yeasts
- candida albicans
- malassezia furfur
What are some viral infections of the skin and name some clinical signs of the infections
- Human papilloma viruses (HPV) - warts
- Herpes simplex virus 1 (HSV1) - cold sores
- Herpes simplex virus 2 (HSV2) - genital warts
- Varicella zoster virus (VZV) - chicken pox, shingles
- Coxsackie A virus - hand, foot and mouth disease
Describe the sarcoptes scabiei (scabies mite)
- Causes scabies
- Mite burrows into skin
- Female lays eggs
- Infection is asymptomatic
- Hypersensitivity may occur
- May lead to super infection
Describe the epidemiology of animal bites
- 250000 cases A&E UK/year
- Dogs make up 80-90% of bites followed by cats the humans
- More common in children than adults
- Site: children - facial/cervical (neck) Adults - extremities
What percentage of each animal’s bite causes infection?
Cat - 80%
Dog - 36%
-Human - 18%
Describe a cat bite
- Small deep wound - 2-5cm
- Usually periphery
- Pasturella spp infection - pasturella multocida
- Cellulitis possible
Describe a dog bite
- Large wound: tearing and crushing
- Usually periphery but can occur anywhere
- Secondary infections: large area damaged, high chance of contamination
- Crush damage comes with its own complication
- Surgery required if extensive superficial damage and crushing
Describe a human bite
- Wide shallow wound
- Can occur anywhere on the body
- Highly polymicrobial
- Deep infection is common, viral infection
What is the animal bite mantra?
The solution to pollution is dilution
What does the animal bite mantra mean?
Washing out the wound is the best way to prevent infection of the body