Skin Infections Flashcards
What is furunculosis?
Deep infection of the hair follicle
What is a boil?
Single hair follicle infected
What is a carbuncle?
Multiple hair follicles infection –> a collection of boils
What are the two most common causes of bacterial skin infection?
Staph aureus Strep pyogenes (group A strep)
What is necrotising fasciitis?
Bacterial infection spreading along the fascial planes beneath the skin surface –> massive tissue destruction
What are the type most common types of bacteria causing necrotising fasciitis?
Mixed anaerobes/coliforms –> post abdominal surgery
Strep pyogenes
What is the treatment for necrotising fasciitis?
Urgent surgical debridement + antibiotics
When is it appropriate to swab a leg ulcer for culture?
Only if signs of infection e.g. cellulitis
Which organisms would be worth treating if cultured from a leg ulcer?
Strep pyogenes
Staph aureus
Other beta-haemolytic strep
Anaerobes
What is the pathology of staph scalded skin syndrome?
Exotoxin produced by staph aureus –> splitting between desmosomes in granular layer
What are the clinical features of staph scalded skin syndrome?
Usually in children
Looked like they’ve been scalded
Widespread erythematous peeling of skin
What is bullous impetigo?
Localised form of staph scalded skin syndrome
What is the treatment for a local bacterial skin infection?
Topical fusidic acid or mupirocin
What does tinea mean?
Fungal infection –> ringworm
Where are the following tinea infections?
- capitis
- unguium
- barbae
- cruris
- corporis
- pedis
- manuum
Scalp Nail Beard Groin Body Foot (athletes foot) Hand
What does ringworm look like?
Scaling, erythematous ring
How is a tinea infection diagnosed?
Clinical
Woods lamp
Send scrapings/hair/nail clippings to lab in Dermapak for microscopy and culture
What is the treatment for tinea infection?
Small area of skin/nail:
- clotrimazole (canestan) cream or similar
- amorolfine nail paint
Extensive skin/nail or scalp infection:
- terbinafine or intraconazole orally
What is intertrigo?
Candida infection in skin folds (warm and moist)
–> under breasts, groin, abdominal folds, nappy area
How is intertrigo treated?
Clotrimazole cream or oral fluconazole
What is chicken pox caused by?
Varicella zoster virus
What are the clinical features of chicken pox?
Macules –> papules –> vesicles –> scabs
Fever and itch
What are some complications of chicken pox?
Secondary bacterial infection Pneumonitis Haemorrhagic rash Scarring Encephalitis
How is at risk of chicken pox complications?
Immunocompromised
Extremely of age e.g. neonates + elderly
What should be done is a pregnant woman gets chicken pox late in pregnancy?
Give VZ Ig or aciclovir to mother to prevent neonatal VZV
What is shingles?
Reactivation of VZV in dermatomal distribution
What are the clinical features of shingles?
Tingling/pain –> erythema –> vesicles –> crusts
What is post herpetic neuralgia and who gets it?
Neuralgic pain for > 4 weeks after shingles
More common if elderly or shingles in a trigeminal distribution
Which pattern of shingles would you be most worried about?
Ophthalamic zoster –> V1 distribution
–> urgent ophthalmologist review
Who gets the shingles vaccine in the UK?
70 year olds
What is otic (ear) herpes zoster also known as?
Ramsay Hunt Syndrome
What are the clinical features of Ramsay Hunt syndrome?
Vesicles and pain in auditory canal and throat
Facial palsy
8th nerve irritation –> deafness, vertigo, tinnitus
Which virus + typecauses cold sores/primary gingivostomatitis?
Herpes simplex virus (HSV) type 1
What is it called when HSV spreads to a finger?
Herpetic whitlow
How are VZV and HSV diagnosed?
Clinically
Viral swab +/- antibody test can be done
What are HSV and VZV treated with?
Aciclovir
What are the clinical features of molluscum contagiosum?
Fleshy, firm, umbilicated, pearlescent nodules, 1-2mm
Self limiting but can last months
Which virus + subtypes cause warts?
HPV 1-4
How can warts be treated?
Topical salicylic acid
Cryotherapy
What is herpangina and what is it caused by?
Blistering rash at back of mouth
–> enteroviruses e.g. coxsackie or echovirus
What causes hand foot and mouth disease?
Enteroviruses especially coxsackie
What are some rare complications of hand foot and mouth disease?
Encephalitis and pulmonary oedema
What is erythema infectiosum and what is it caused by?
Slapped cheek –> parvovirus B19
What are the clinical features of slapped cheek/erythema infectiosum?
Rash of face first, then fades –>
lacy macular rash on body + acute arthritis e.g. wrists
How is slapped cheek diagnosed?
Parovirus B19 IgM test
What is rubella also known as, and what are the clinical features?
German measles
Spotty rash, starts behind ears, spreads to head, neck and body
Lymphadenopathy, aching joints and fever
What is the management of rubella and when can it be dangerous?
Usually resolves without treatment
Dangerous if pregnant
What are the features of measles?
Red blotchy rash
Fever, cough, runny nose, inflamed eyes
What is Orf and what are the clinical features?
Virus from sheep –> ‘scabby mouth’
Firm fleshy nodule on the hands of farmers
Self limiting
What is syphilis caused by?
Treponema pallidum –> STI
What are the features of primary syphilis infection?
Chancre –> painful ulcer at site of entry
What are the features of secondary syphilis?
Red rash all over body –> prominent on soles and palms
Mucous membrane ‘snail track’ ulcers
How is syphilis diagnosed?
Blood test or swab of ulcer for PCR
What is the treatment for syphilis?
IM penicillin
What are the features of tertiary syphilis?
Can affect any system e.g. CNS, cardiovascular, gummatous
