Skin Infections Flashcards
What is ringworm?
Tinea corporis
What are the features of tinea corporis?
Scaly, annular lesions on body
Itchy
Spreading
Central clearing
What are the common pathogens causing tinea corporis?
Tricophyton rubrum
Microsporum canis
Epidermophyton floccosum
Where does tinea pedis occur?
On feet
What are two subtypes of tinea pedis?
Interdigital tinea pedis
Moccasin tinea pedis
Where does tinea unguium occur?
Nails
What region of the body is a reservoir for tinea pedis?
Toenails
How is tinea unguium treated?
Too deep to be treated topically
Have to use oral antifungals; eg: terbinafine for 3-6 months
What is jock itch?
Tinea cruris
Where does tinea capitis occur?
On scalp
In whom does tinea capitis occur?
Rare in adults
Can occur in children
What is the treatment for tinea capitis and why?
Potentially scarring > needs aggressive treatment with
- Systemic antifungals for 2 months
- Griseofulvin
- Terbinafine
- Oral steroids
How is a diagnosis of tinea confirmed?
Scraping for fungal microscopy and culture
What is the management of tinea?
Confirm diagnosis with scrapings and cuture Topical agents for 3-4 weeks - Imidazole - Terbinafine Extensive skin infections respond to - Oral griseofulvin for 4 weeks - Terbinafine - Itraconazole - Fluconazole Look for reservoir
Why is the use of cortisone cream contraindicated in the treatment of tinea?
Fungus causing tinea loves it
How long is the prodrome for varicella?
2 weeks
What are the features of a primary VZV infection?
Fevers Crops of - Papules - Vesicles - Pustules - Then crusts Can be mucosal Trunk and heads > limbs
What causes shingles?
VZV reactivation in dorsal ganglion
What are the features of shingles?
Unilateral dermatomal rash Prodrome - Neuralgic pain - Tingling Eruption of - Papules - Vesicles - Crusts
How is shingles diagnosed?
Zoster PCR
What is the treatment for shingles?
Systemic antiviral
What are the complications of shingles?
Post-herpetic neuralgia
Ophthalmic involvement
What causes cold sores?
HSV 1
What are the features of cold sores?
Crops of vesicles on lips
What is the treatment for cold sores?
Topical/systemic acyclovir/other antiviral
What causes genital herpes?
HSV 2
What are the features of genital herpes?
Crops of vesicles on genital areas
STI
How is herpes diagnosed?
HSV PCR
What is the treatment for genital herpes?
Systemic antivirals
May need prophylaxis
What should you consider in herpetic infections?
Risk of exposure in pregnancy
Infectious disease > isolation
Immunosuppressed patients
Ophthalmic involvement
What is molluscum contagiosum?
Skin infectious caused by molluscum contagiosum virus (MCV)
What are the features of molluscum contagiosum?
Common disease of childhood
Outbreaks in family common
Polymorphous umbilicated skin coloured papules
How is molluscum contagiosum managed?
Showers not baths
Restrict sharing of bath towels
Concurrent eczema treated with topical steroids
Topical irritants; eg: salicylic acid wart paint
Topical immunostimulants; eg: dilute imiquimod cream
Destructive methods; eg: topical cantharidine treatment
What causes warts?
HPV types
What is the commonest type of wart?
Verruca vulgaris
What are other types of warts?
Plane Periungual Filliform Mosaic Anogenital > carcinogenic potential in females
What is the management of viral warts?
Depends on - Number - Site - Patient factors Treatments often used in combination Consider when planning - Spontaneous remission rates - Risk of scarring by treatments - Trauma of treatment - Cure rate for placebo
What is the destructive treatment of viral warts?
Liquid nitrogen cryotherapy
Diathermy
Curettage
What is the topical treatment of viral warts?
Salicylic acid and other keratolytics
DCP immunotherapy
Imiquimod for genital warts
Tape
What organisms cause the majority of cutaneous bacterial infections?
Staphylococcus aureus
Group A Streptococcus
What usually causes folliculitis?
S aureus
How do you investigate folliculitis?
Swab for bacterial culture and sensitivity
Where do you look for S aureus carriage?
Nares
Axillae
Groin
How is folliculitis treated?
Systemic antibiotics
Eradicate carriage
Antiseptic washes helpful in maintenance
What causes impetigo?
Exfoliative toxin of S aureus
What is the treatment for impetigo?
Anti-Staph antibiotics
What are the symptoms associated with cellulitis?
Febrile
Systemically unwell
What usually causes cellulitis?
Group A Strep
What is the treatment for cellulitis?
IV antibiotics
Severe cases need surgical intervention
