Infections Flashcards
Folliculitis?
Follicular erythema, sometimes pustular
Infectious or non-infectious
Eosinophilia folliculitis associated with HIV
Recurrent may arise from Staph a
Which staph a can cause recurrent folliculitis?
Panton-Valentine leukocidin (PVL)
Folliculitis treatment?
Antibiotics (flucloxacillin or erythromycin)
Incision and drainage for furunculosis
Furnuncle vs carbuncle?
Furuncle - deep folicular abscess
Carbuncle - involvement with adjacent follicles, more likely to lead to complications like cellulitis and septicaemia
Staph a infections - immunodeficiency?
Hypogammaglobulinaemia
HyperIgE syndrome
Chronic Granulomatous disease
AIDS
Diabetes mellitus
Panton Valentin Leukocidin Staph a?
Beta-pore-forming exotoxin, leukocyte destruction and tissue necrosis
Higher morbidity, mortality and transmissibility
Panton Valentin Leukocidin Staph a? Skin
Recurrent and painful abscesses, folliculitis, cellulitis
Often painful, more than 1 site, recurrent, present in contacts
Panton Valentin Leukocidin Staph a? Extracutaneous
Necrotising pneumonia
Necrotising fasciitis
Purpura fulminans
Panton Valentin Leukocidin Staph a risk of acquiring? 5 Cs.
Close contact
Contaminated items
Crowding
Cleanliness
Cuts and grazes
Panton Valentin Leukocidin Staph a? Treatment
ABx (tetracycline)
Decolonisation - chlorehexidine body wash for 7 days, nasal application of mupirocin ointment 5 days
Treatment of close contacts
Cellulitis? What, symptoms + treatment
Infection of lower dermis and subcutaneous tissue
Tender swelling with ill-defined, blanching erythema or oedema
Most cases - strep p + staph a
Oedema predisposing factor
Treatment - systemic ABx
Impetigo?
Superficial bacteria infection, stuck on, honey-coloured crusts overlying an erosion
Causes by strep (non-bullous) or staph (bullous)
Often affects face
Treatment with topical +/- systemic ABx
Streptococci vs staphylococci impetigo?
Strep - non-bullous
Staph - bullous, caused by exfoliative toxins A & B, split epidermis by targeting desmoglein I
Impetiginisation?
Occurs in atopic dermatitis
-gold crust
-staph aureus
Borreliosis? Meaning
Lyme disease
Annular erythema develops at site of bite of a borrelia-infected tick
Bite form Ixodes tick infected with Borrelia burgdorferi
Lyme disease initial cutaneous manifestation?
Erythema migrans (in 75%):
-erythematosus papule at bite site
-progression to annular erythema of >20cm
Lyme disease 1-30 days after infection, fever and headache?
Multiple secondary lesions develop - similar but smaller to initial
Neuroborreliosis
Arthritis (knee)
Carditis
Neuroborreliosis?
-facial palsy
-aseptic meningitis
-polyradiculitis
Syphilis? Primary
Primary infection Chancre - painless ulcer with a firm indurated border
Painless regional lymphadenopathy one week after primary chancre
Chancre appears within 10-90 days
Secondary syphilis?
Begins around 50 days after chancre
Malaise, fever, headache, Pruritus, loss of appetite, iritis
Rash, alopecia (moth eaten), mucous patches, lymphadenopathy, residual primary chancre, condylomata lata, hepatosplemomegaly
Syphilis - lues maligna?
Rare manifestation of secondary syphilis
Pleomorphic skin lesions with pustules, nodules and ulcers with necrotising vasculitis
More frequent in HIV manifestation
Tertiary syphilis?
Gummy skin lesions - nodules and plaques
Extended peripherally while central areas heal with scarring and atrophy
Mucosal lesions extend to and destroy nasal cartilage
CVD
Neurosyphilis - general pareses or tabes dorsalis
Syphilis treatment?
IM benzylpenicillin or oral tetracycline
Herpes Simplex Virus? What, where and how
Primary and recurrent vesicular eruptions
Favour orolabial and genital regions
Transmission can occur even during asymptomatic periods of viral shedding
Replicates at mucocutaneous site of infection
Travels by retrograde axonal flow to dorsal root
HSV 1 vs 2?
HSV-1 - direct contact with contaminated saliva/other infected secretions
HSV-2 - sexual contact
HSV symptoms?
Symptoms within 3-7 days
Preceded by tender lymphadenopathy, malaise, anorexia +/- burning, tingling
Painful rouped vesicles on erythematosus base -> ulceration/pustules/erosions with scalloped border
Crusting and resolution within 2-6 weeks
HSV orolabial lesions?
Often asymptomatic
HSV genital involvement?
Orfeo excruciatingly painful - urinary retention
HSV systemic manifestations?
Aseptic meningitis in up to 10% of omen
HSV reactivation?
Spontaneous, UV, fever, local tissue damage, stress
Eczema herpeticum?
Emergency
Monomorphic, punched out erosions (excoriated vesicles)
Herpes whitlow?
HSV (1>2) infection of digits - pain, swelling and vesicles
Misdiagnosed as paronychia or dactylitis
Often in children
Neonatal HSV?
Exposure to HSV during vaginal delivery - risk higher when HSV acquired near time of delivery
1 or 2
Onset from birth to 2 weeks
Localised usually - scalp or trunk
Vesicles - bullae erosions
Encephalitis
Requires IV antivirals
Severe or chronic HSV?
Immunocompromised patients
Most common presentation - chronic, enlarging ulceration
Multiple sites or disseminated
Often atypical
Involvement of resp or GI tract possible
HSV diagnosis and treatment?
Swab for PCR
Oral valacyclovir or acyclovir
Fungal infections subclassifications?
Superficial
Deep/soft tissue
Disseminated
Superficial fungal infections? Pityriasis versicolor
Hypo/hyper pigmented or erythematosus macular eruption +/- fine scale
Begins during adolescence (when sebaceous glands become active)
Flares when temperatures and humidity are high
Topical azole
Dermatophytes?
Fungi that live on keratin
What causes the most fungal infections?
Trichiphyton rubrum
Kerion?
An inflammatory fungal infection that may mimic a bacterial folliculitis or an abscess of the scalp - scalp is tender and patient usually has posterior cervical lymphadenopathy
Frequently secondary to staph a
Superficial fungal infections signs
Tinea pedis
Onychomycosis
Maceration between toes
Kerion formation
TOM K
Id reaction? Superficial fungal infections
Dermatophytid reactions
Inflammatory reactions at sites distant from associated dermatophyte infection
May include urticaria, hand dermatitis, or erythema nodosum
Candidiasis? (Superficial fungal infections)
Candida albicans
Predisposition - occlusion, moisture, warm temp, DM
Most sites show erythema oedema, thin purulent discharge
Usually intertriginous infection (skin folds) or of oral muscosa
Common cause of vulvovaginitis
Can become systemic
Opportunistic fungal infections? Mucormycosis
Oedema, then pain, then eschar
Fever, headache proptosis, facial pain, orbital cellulitis +/- CN dysfunction
Associations - DM, malnutrition, uraemia, neutropenia, steroids ABx, burns, HIV
Mucormycosis (opportunistic) treatment?
Aggressive debridement and anti fungal therapy amphoteracin
Scabies?
Caused by Sarcoptes species
Female mates, burrows into upper epidermis, lays eggs then dies after one month
Insidious onset - red to flesh coloured Pruritic papules
Affects interdigital areas of digits, volar wrists, axillary areas and genitalia
diagnostic burrow consisting of fine white scale
Crusted or ‘Norwegian’ scabies?
Hyperkeratosis
Often asymptomatic
Scabies treatment?
Permethrin, oral ivermectin
2 cycles required
