Infections

Question 1

Folliculitis?

Answer 1

Follicular erythema, sometimes pustular
Infectious or non-infectious
Eosinophilia folliculitis associated with HIV
Recurrent may arise from Staph a

Question 2

Which staph a can cause recurrent folliculitis?

Answer 2

Panton-Valentine leukocidin (PVL)

Question 3

Folliculitis treatment?

Answer 3

Antibiotics (flucloxacillin or erythromycin)
Incision and drainage for furunculosis

Question 4

Furnuncle vs carbuncle?

Answer 4

Furuncle - deep folicular abscess

Carbuncle - involvement with adjacent follicles, more likely to lead to complications like cellulitis and septicaemia

Question 5

Staph a infections - immunodeficiency?

Answer 5

Hypogammaglobulinaemia
HyperIgE syndrome
Chronic Granulomatous disease
AIDS
Diabetes mellitus

Question 6

Panton Valentin Leukocidin Staph a?

Answer 6

Beta-pore-forming exotoxin, leukocyte destruction and tissue necrosis
Higher morbidity, mortality and transmissibility

Question 7

Panton Valentin Leukocidin Staph a? Skin

Answer 7

Recurrent and painful abscesses, folliculitis, cellulitis
Often painful, more than 1 site, recurrent, present in contacts

Question 8

Panton Valentin Leukocidin Staph a? Extracutaneous

Answer 8

Necrotising pneumonia
Necrotising fasciitis
Purpura fulminans

Question 9

Panton Valentin Leukocidin Staph a risk of acquiring? 5 Cs.

Answer 9

Close contact
Contaminated items
Crowding
Cleanliness
Cuts and grazes

Question 10

Panton Valentin Leukocidin Staph a? Treatment

Answer 10

ABx (tetracycline)
Decolonisation - chlorehexidine body wash for 7 days, nasal application of mupirocin ointment 5 days
Treatment of close contacts

Question 11

Cellulitis? What, symptoms + treatment

Answer 11

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

Question 12

Impetigo?

Answer 12

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

Question 13

Streptococci vs staphylococci impetigo?

Answer 13

Strep - non-bullous

Staph - bullous, caused by exfoliative toxins A & B, split epidermis by targeting desmoglein I

Question 14

Impetiginisation?

Answer 14

Occurs in atopic dermatitis
-gold crust
-staph aureus

Question 15

Borreliosis? Meaning

Answer 15

Lyme disease
Annular erythema develops at site of bite of a borrelia-infected tick
Bite form Ixodes tick infected with Borrelia burgdorferi

Question 16

Lyme disease initial cutaneous manifestation?

Answer 16

Erythema migrans (in 75%):
-erythematosus papule at bite site
-progression to annular erythema of >20cm

Question 17

Lyme disease 1-30 days after infection, fever and headache?

Answer 17

Multiple secondary lesions develop - similar but smaller to initial
Neuroborreliosis
Arthritis (knee)
Carditis

Question 18

Neuroborreliosis?

Answer 18

-facial palsy
-aseptic meningitis
-polyradiculitis

Question 19

Syphilis? Primary

Answer 19

Primary infection Chancre - painless ulcer with a firm indurated border
Painless regional lymphadenopathy one week after primary chancre
Chancre appears within 10-90 days

Question 20

Secondary syphilis?

Answer 20

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

Question 21

Syphilis - lues maligna?

Answer 21

Rare manifestation of secondary syphilis
Pleomorphic skin lesions with pustules, nodules and ulcers with necrotising vasculitis
More frequent in HIV manifestation

Question 22

Tertiary syphilis?

Answer 22

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

Question 23

Syphilis treatment?

Answer 23

IM benzylpenicillin or oral tetracycline

Question 24

Herpes Simplex Virus? What, where and how

Answer 24

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

Question 25

HSV 1 vs 2?

Answer 25

HSV-1 - direct contact with contaminated saliva/other infected secretions HSV-2 - sexual contact

Question 26

HSV symptoms?

Answer 26

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

Question 27

HSV orolabial lesions?

Answer 27

Often asymptomatic

Question 28

HSV genital involvement?

Answer 28

Orfeo excruciatingly painful - urinary retention

Question 29

HSV systemic manifestations?

Answer 29

Aseptic meningitis in up to 10% of omen

Question 30

HSV reactivation?

Answer 30

Spontaneous, UV, fever, local tissue damage, stress

Question 31

Eczema herpeticum?

Answer 31

Emergency Monomorphic, punched out erosions (excoriated vesicles)

Question 32

Herpes whitlow?

Answer 32

HSV (1>2) infection of digits - pain, swelling and vesicles Misdiagnosed as paronychia or dactylitis Often in children

Question 33

Neonatal HSV?

Answer 33

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

Question 34

Severe or chronic HSV?

Answer 34

Immunocompromised patients Most common presentation - chronic, enlarging ulceration Multiple sites or disseminated Often atypical Involvement of resp or GI tract possible

Question 35

HSV diagnosis and treatment?

Answer 35

Swab for PCR Oral valacyclovir or acyclovir

Question 36

Fungal infections subclassifications?

Answer 36

Superficial Deep/soft tissue Disseminated

Question 37

Superficial fungal infections? Pityriasis versicolor

Answer 37

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

Question 38

Dermatophytes?

Answer 38

Fungi that live on keratin

Question 39

What causes the most fungal infections?

Answer 39

Trichiphyton rubrum

Question 40

Kerion?

Answer 40

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

Question 41

Superficial fungal infections signs

Answer 41

Tinea pedis Onychomycosis Maceration between toes Kerion formation *TOM K*

Question 42

Id reaction? Superficial fungal infections

Answer 42

Dermatophytid reactions Inflammatory reactions at sites distant from associated dermatophyte infection May include urticaria, hand dermatitis, or erythema nodosum

Question 43

Candidiasis? (Superficial fungal infections)

Answer 43

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

Question 44

Opportunistic fungal infections? Mucormycosis

Answer 44

Oedema, then pain, then eschar Fever, headache proptosis, facial pain, orbital cellulitis +/- CN dysfunction Associations - DM, malnutrition, uraemia, neutropenia, steroids ABx, burns, HIV

Question 45

Mucormycosis (opportunistic) treatment?

Answer 45

Aggressive debridement and anti fungal therapy amphoteracin

Question 46

Scabies?

Answer 46

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*

Question 47

Crusted or ‘Norwegian’ scabies?

Answer 47

Hyperkeratosis Often asymptomatic

Question 48

Scabies treatment?

Answer 48

Permethrin, oral ivermectin 2 cycles required