Skin infections Flashcards
Difference between cellulitis and erysipelas
Erysipelas: More superficial, dermis and subcut tissue. RED RAISED WELL-DEMARCATED BORDER
Cellulitis: Inflammation of deep subcut tissues
Both need oral abx
Common causative agents for cellulitis/erysipelas
Strep pyogenes - treat with penicillin/erythromycin
Staph aureus - treat with flucloxacillin/erythromycin
Risk factors for cellulitis/erysipelas
Immunosuppression
Wounds/surgery
Ulcers
Toeweb intertrigo
Presentation of herpes simplex
Fever, lymphadenopathy
Gingivostomatitis - white vesicles > yellow ulcers in mouth and gums
HSV2 - Genital vesicles, painful/itchy, red, swollen
Paronychia esp in healthcare workers
Complications of herpes simplex
Eczema herpeticum - Rx eczema, aciclovir, abx
Dendritic ulcer - HSV in cornea, seen with fluorescein
Herpes encephalitis
Erythema multiforme
Presentation of herpes zoster
Pain, then blistering rash in dermatomal distribution
Ramsay-Hunt Syndrome if ophthalmic division affected - ophtho review
Usually in elderly (reactivation)
Treat w/ IV acyclovir in first 48-72h
Presentation of molluscum contagiosum
Umbilicated papules (1-6mm)
Child <10yo
Papules contain white, cheesy material
Itchy, often with surrounding dermatitis
Do not occur on palm/soles > preference for warm, moist areas
Resolve spontaneously
Appearance of viral warts
HPV infection –> keratinocyte proliferation
Papules with hyperkeratotic surface
Topical salicylic acid for palm/foot
imiquimod/podophyllin for genital
Presentation of impetigo
Moist crusting surface
Epidermal infection
Common in children
Skin swab investigation + abx treatment
If blistering - bullous impetigo due to toxins vs desmoglein
Crust vs scale
Crust = dried sebum/pus/blood
Often bacterial/viral
Scale = dead keratinocytes - superficial/epidermal pathology
Staphylococcal scalded skin syndrome pathophysiology
Panton-Valentine leukocidin toxin producing staph
Often more virulent and penicillin resistant
Epidermolytic
Preentation of PVL+ve staph infx
Infancy/early childhood
Perioral crusting, intraepidermal blistering, necrotic lesions
Painful, ‘scalded skin’ type lesion followed by large flaccid bulla
Develops over hours-days
Lasts 5-7d
Treatment of PVL +ve staph
Clindamycin
Analgesia
Presentation of tinea
Well-demarcated
Itchy
Annular, red raised border
Scaly/fissured
Presentation of tinea capitum
Inflammation + hair loss
Scaly
Presentation of tinea unguinum
Yellow discolouration
Thickened, crumbly nail
Presentation of tinea incognito
Less scaly
Poorly demarcated
Treatment of tinea with steroids
Presentation of candidiasis
White plaques in mucosal areas
Erythema with satellite lesions in flexures
Management of tinea
Skin scraping/scalp brush/nail clippings for culture
Correct predisposing factors: immunosuppression, moistness
Topical antifungal for pedis - clotrimazole
Oral antifungal for others - terbinafine
Presentation of scabies infection
Itch: 4-6w after infestation, very itchy, worse at night, associated with grey burrows, spares scalp
Burrows are mite infestation in stratum corneum
Rash: Several weeks after infestation, hypersensitivity reaction w/ erythema, urticaria, vesicles/papules
Management of scabies
Contact tracing/screening
Was sheets/pillows/towels etc in hot water with start of treatment
Treat entire household with scabicide - topical pertmethrin for 24h
Rash persists for several weeks after treatment
Risk factors for scabies
Poverty/overcrowdding
Refugee camps
Institutional care
Immunosuppression
Presentation of crusted (Norwegian) scabies
Generalised scaly rash - esp wrists, finger webs, elbows, scrotum, breasts
Itch may be mild/absent - often misdiagnosed as psoriasis
Highly contagious!
Immunosuppressed/malnourished individuals or LD/neuro deficit
Treat w/ oral ivermectin
