Skin Infections Flashcards
Impetigo causative organism
Staph aureus Strep pyogenes (GAS)
Presentation of impetigo
Golder crusting
Inflamed plaques
Around nose and mouth
Children
Treatment of impetigo
Topical antibiotics: Fusidic acid (1st), mupirocin (MRSA) Oral antibiotics (if severe): Flucloxacillin (1st), clarithromycin
What is cellulitis?
Infection of the dermis and subcutaneous tissue
What is impetigo and how does it spread?
Superficial bacterial infection of the skin
Spread: direct contact, very contagious
What is eyrsipelas?
Superficial form of cellulitis caused by infection with group A strep/strep pyogenes
Cellulitis causative organism
Staph aureus
Beta-haemolytic strep: (GAS/GBS)
Presentation of cellulitis
Generalised swelling, pain, erythema
Treatment of cellulitis
Flucloxacillin (or doxycycline if penicillin allergic)
What is necrotising fasciitis?
Rapidly progressive infection of the deep fascia causing necrosis of subcutaneous tissue
Presentation of necrotising fasciitis
Disproportional pain to visible symptoms (similar to cellulitis)
Feels like bubble wrap
Investigation of necrotising fasciitis
Blood culture, deep tissue biopsy and Gram stain to identify causative organism
Treatment of necrotising fasciitis
Radical debridement +/- amputation IV antibiotics (flucloxacillin + clindamycin + gentamicin)
Lyme disease causative organism and vector
Borreli burgdoferi
Ticks
Lyme disease presentation
Erythema migrans (bullseye lesion)
Complications of Lyme disease
Heart block
Nerve palsies
Arthritis
Treatment of Lyme disease
Amoxicillin or doxycycline
Chickenpox spread
Air droplets
Chickenpox and shingles causative organism
Varicella zoster virus
reactivation in shingles
Chickenpox presentation
Fever
Itch
Macules –> papules –> vesicles –> scabs
Centripetal (rash is concentrated at the centre of the body)
Complications of chickenpox
Secondary bacterial infection
Pneumonitis
Haemorrhagic rash
Encephalitis
Treatment of chickenpox
Goes away itself (week)
Don’t take ibuprofen as it can cause skin infections
Presentation of shingles
Tingling/pain –> erythema –> vesicles –> crusts
Rash restricted to one dermatome
Complications of shingles
Post-herpetic neuralgia
Treatment of shingles
No definitive treatment
Aciclovir can aid recovery
Vaccine for chickenpox can be used in high titre preparations in elderly patients to reduce the impact of shingles
Other names of erythema infectiosum
Fifth disease
Slapped cheek
Erythema infectiosum causative organism
Parvovirus B19
Presentation of erythema infectiosum
Red cheeks with palpable raised edge (slapped cheek)
Complications of erythema infectiosum
Arthritis and joint pain
Aplastic crisis
Spontaneous abortion
Hand, foot and mouth disease causative organism
Enteroviruses: e.g. coxsackie virus
Presentation of hand, foot and mouth disease
Sore throat Fever Not wanting to eat Mouth ulcers Red spots that become blisters on the hands and feet
Complications of hand, foot and mouth disease
Viral meningitis
Encephalitis
HSV-1 causes…
Infections above the waist (generally)
Causes half of genital herpes
Main cause of oral lesions
Primary gingivostomatitis
HSV-2 causes…
Infections below the waist (generally)
Causes half of genital herpes
Investigations for herpes
Swab of lesion in virus transport medium:
PCR for detection or viral DNA
Antibody tests:
Where virus infected site is inaccessible
What animal can you get orf from?
Sheep infected with parapoxvirus
Presentation of orf
Firm, fleshy nodules on hands
Treatment of candida infection
Antifungals: clotrimazole (topical), nystatin (topical), fluconazole (oral)
Candida
Fungal infection in skin folds where area is warm and moist
Tinea (ringworm)
Fungal infection of the skin, scalp or nail
Investigations for tinea
Skin scrapings, nail clippings, hair: for microscopy + culture and fluorescence under Woods light
Treatment of tinea
Small areas: clotrimazole (topical), terbinafine (topical), amorolfine (topical nail paint)
Widespread infection: terbinafine (oral, when nails are affected too), itraconazole (last resort drug, has many interactions)
Presentation of lice (pediculosis)
Intense itch
Treatment of lice (pediculosis)
Malathion
Scabies causative organism
Sarcoptes scabiei
Presentation of scabies
Intense itch (particularly at night)
Areas: finger webs, wrists, genitals
Burrows can also be seen
Treatment of scabies
Permethrin lotion (1st line)
Malathion
Benzyl benzoate (not in children)
Anti-pruritic
