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BRS Year 2 > derm infestation + infect skin > Flashcards

derm infestation + infect skin Flashcards

(100 cards)

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1
Q

important tests for infective cause of derm tissue?

A
  • swabs
  • serum
  • tissue samples
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2
Q

how does staphyococcus attack the skin?

A
  • receptors that allow it to bind to fibrin: this is found on wound surfaces + in dermatitis
  • via panto valentine leukocidin
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3
Q

what can staph infection cause?

A

Ecthyma
Impetigo
Cellulitis

Folliculitis
- Furunculosis
- Carbuncles
Staphylococcal scalded skin syndrome (SSSS)
Superinfects other dermatoses (e.g. atopic eczema, HSV, leg ulcers)

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4
Q

how does strep attack?

A

Strepococcus pyogenes (β-haemolytic) attaches to epithelial surfaces via lipoteichoic acid portion of fimbriae

- Has M protein (anti-phagocytic) & hyaluronic acid capsule
- Produces erythrogenic exotoxins
- Produces streptolysins S and O
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5
Q

how does strep present?

low priority card

A

Ecthyma
Cellulitis
Impetigo

Erysipelas
Scarlet fever
Necrotizing fasciitis

Superinfects other dermatoses (e.g. leg ulcers)

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6
Q

what is eosinophilic (non infectious) folliculitis associated with?

A

HIV

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7
Q

treatment for folliculitis?

A

Antibiotics (usually flucloxacillin or erythromycin)

Incision and drainage is required for furunculosis.

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8
Q

folliculitis recurrent cases may arise from?

A

from nasal carriage of Staphylococcus aureus, particularly strains expressing Panton-Valentine leukocidin (PVL).

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9
Q

What is the difference between a furuncle and a carbuncle?

A

A furuncle is a deep follicular abscess
- Involvement with adjacent connected follicles = Carbuncle.

Carbuncle - more likely to lead to complications such as cellulitis and septicaemia

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10
Q

Why do some patients develop recurrent staphylococcal impetigo or recurrent furunculosis?

A

Establishment as part of the resident microbial flora:
-abundant nasal flora

Immune deficiency:

  • Hypogammaglobulinaemia
  • HyperIgE syndrome – deficiency
  • Chronic granulomatous disease
  • AIDS
  • Diabetes Mellitus
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11
Q

Where is Staphylococcus aureus most abundant?

A

nasal flora

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12
Q

Panton Valentine Leukocidin Staphylococcus Aureus features?

A

Beta pore forming exotoxin
Leukocyte destruction and tissue necrosis
Higher morbidity, mortality and transmissibility
Skin:
- Recurrent and painful abscesses
- Folliculitis
- Cellulitis
- Often painful, more than 1 site, recurrent, present in contacts

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13
Q

extracutaneous Panton Valentine Leukocidin Staphylococcus Aureus symptoms?

A
  • Necrotising pneumonia
  • Necrotising fasciitis
  • Purpura fulminans
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14
Q

Panton Valentine Leukocidin Staphylococcus Aureus : risks

A

5 Cs
Close Contact – e.g. hugging, contact sports
Contaminated items , e.g. gym equipment, towels or razors.
Crowding –crowded living conditions such as e.g. military accommodation, prisons and boarding schools.
Cleanliness (of environment)
Cuts and grazes – having a cut or graze will allow the bacteria to enter the body

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15
Q

how to treat Panton Valentine Leukocidin Staphylococcus Aureus

A

Consult local microbiologist/ guidelines
Antibiotics
Decolonisation:
* Chlorhexidine body wash for 7 days
* Nasal application of mupirocin ointment 5 days)

Treatment of close contacts

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16
Q

What is Pseudomonal Folliculitis associated with amd how does it present?

A

hot tub use, swimming pools and depilatories, wet suit

Appears 1-3 days after exposure, as a diffuse truncal eruption.
Follicular erythematous papule

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17
Q

treatment of Pseudomonal Folliculitis?

A

usually none required
Rarely can cause abscesses, lymphangitis + fever
- severe/recurrent cases treated with oral ciprofloxacin

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18
Q

What is cellulitis?

A

Infection of lower dermis and subcutaneous tissue

Tender swelling with ill-defined, blanching erythema or oedema

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19
Q

what predisposes to cellulitis and whats causes it?

A

Predisposed by oedema

Most causes caused by s.pyogenes and s. aures

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20
Q

how to treat cellulitis?

A

systemic ABs

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21
Q

Features of impetigo

A

Superficial bacterial infection
Looks like stuck-on, honey-coloured crusts overlying an erosion.
Often affects face

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22
Q

What causes impetigo?

A

Streptococci (non-bullous)
or
Staphylococci (bullous)

Caused by exfoliative toxins A & B, split epidermis by targeting desmoglein I.

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23
Q

How to treat impetigo?

A

topical +/- systemic antibiotics.

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24
Q

Impetiginisation observations?

A

Occurs in atopic dermatitis

- Gold crust
- Staphylococcus aureus
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25
What is Ecthyma?
Severe form of streptococcal impetigo Thick crust overlying a punch out ulceration surrounded by erythema Usually on lower extremities
26
Who's at risk of Staphylococcal Scalded Skin Syndrome
Neonates, infants or immunocompromised adults
27
What is the cause of scalded skin syndrome (not organism, but the toxin!)
Due to exfoliative toxin
28
Why can't the organism be cultured from denuded skin in scalded skin syndrome?
Infection occurs at distant site (ie conjunctivitis or abscess) The organism can't be cultured from the site of skin damage
29
How does staphylococcal scaled skin syndrome affect neonates?
→ Diffuse tender erythema → Rapid progression to flaccid bullae, → Wrinkle and exfoliate, leaving oozing erythematous base In neonates, kidneys cannot excrete the exfoliative toxin quickly
30
What does scalded skin syndrome look like?
Stevens-Johnson syndrome / toxic epidermal necrolysis
31
What causes toxic shock syndrome?
Group A Staphylococcus aureus strain that produces pyrogenic exotoxin TSST-1
32
signs of toxic shock syndrome
``` Fever >38.9°C Hypotension Diffuse erythema Involvement of multiple systems: – Gastrointestinal – Muscular – CNS - Renal - Hepatic Effects mucous membranes (erythema) Hematologic (platelets <100 000/mm3) Desquamation predominantly of palms and soles 1-2 weeks after resolution of erythema ```
33
What causes erythasma?
Infection of Corynebacterium minutissimum Well demarcated patches in intertriginous areas (e.g. armpit) - initially pink - Become brown and scaly
34
Pitted Keratolysis cause + treatment
1. Caused by Corynebacteria | 2. Treated with topical clindamycin.
35
Erysipeloid cause?
Erysipelothrix rhusiopathiae - looks like cellulitis but slower spreading - Associated with handling contaminated raw fish or meat.
36
Anthrax organism?
Bacillus anthracis
37
How does anthrax present?
``` Painless necrotic ulcer with surrounding oedema and regional lymphadenopathy (with pain in lymph nodes) at the site of contact with: hides bone meal wool or infected with Bacillus anthracis ```
38
Blistering Distal Dactylitis - rare- what causes it?
Streptococcus pyogenes or Staphylococcus aureus
39
who suffers with Blistering Distal Dactylitis
young children
40
signs/symptoms blistering distal dactylitis?
1 or more tender superficial bullae on erythematous base on the volar fat pad of a finger Toes may rarely be affected
41
What is erysipelas and what are causes and symptoms?
Infection of deep dermis and subcutis Caused by B- haemolytic streptococci or s. aures Painful Prodrome of malaise, fever, headache Presents as erythematous indurated plaque with a sharp demarcated border and a cliff drop edge (+/- blistering) May effect face or limb: - red streak of lymphangitis and local lymphadenopathy
42
how to treat Erysipelas?
IV ABs
43
Scarlet fever cause?
Caused by upper respiratory tract infection with erythrogenic toxin-producing Streptococcus pyogenes
44
Cause of necrotising fasciitis
streptococci, staphylococci, enterobacteriaceae and anaerobes.
45
when Necrotising fasciitis affects the scrotum?
(Fournier’s gangrene).
46
Which group is more vulnerable to Atypical Mycobacterial Infection
people in immunocompromised states
47
What does Mycobacterium marinum cause
indolent granulomatous ulcers (fish-tank granuloma) in healthy people - Sporotrichoid spread
48
What can cause Mycobacterium chelonae?
puncture wounds, tattoos, skin trauma or surgery
49
What Mycobacterium ulcerans lead to?
an important cause of limb ulceration in Africa (Buruli ulcer) or Australia (Searle’s ulcer).
50
Borreliosis (Lyme Disease) manifestation?
Annular erythema develops at site of the bite of a Borrelia-infected tick Bite from Ixodes tick infected with Borrelia burgdorferi Initial cutaneous manifestation- erythema migrans (only in 70%): - erythematous papule at bite site -progression to annular erythema of >20cm
51
What happens 1-30 days after initial bite in lyme disease?
``` infection, fever, headache Multiple secondary lesions develop - similar but smaller to initial lesion Neuroborreliosis - Facial palsy / other CN palsies - Aseptic meningitis - Polyradiculitis Arthritis – painful and swollen large joints (knee is the most affected join) Carditis ```
52
How to diagnose lyme disease?
Serology not sensitive Histopathology - non-specific High index of suspicion required for diagnosis
53
Cause of Tularaemia
Francisella tularensis Acquired through: - Handling infected animals (squirrels and rabbits) - Tick bites - Deerfly bites
54
systemic symptoms + signs of tularaemia
systemic: fever, chills, headache and malaise other: Painful regional lymphadenopathy
55
Ecthyma Gangrenosum cause
Pseudomonas aeruginosa
56
Who is @ risk of Ecthyma Gangrenosum
neutropaenic patients
57
development of Ecthyma gangrenosum
Red macule(s) → oedematous → haemorrhagic bullae. May ulcerate in late stages or form an eschar surrounded by erythema
58
cause of syphilis
Treponema pallidum
59
progression of syphilis
Primary infection Chancre -painless ulcer with a firm indurated border Painless regional lymphadenopathy one week after the primary chancre Chancre appears within 10-90 days
60
why is it hard to diagnose syphilis when looking at signs/symptoms secondary symphilis?
Great mimicker’ – low threshold for testing - Rash (88-100%) -Pityriasis rosea-like rash - Alopecia (‘moth-eaten’) - Mucous patches - Lymphadenopathy - Residual primary chancre - Condylomata lata - Hepatosplenomegaly
61
secondary syphilis signs/symptoms
Malaise, fever, headache, pruritus, loss of appetite, iritis
62
What is Lues maligna?
Rare manifestation of secondary syphilis Pleomorphic skin lesions with pustules, nodules and ulcers with necrotising vasculitis More frequent in HIV manifestation
63
Tertiary syphilis | (5)
Gumma Skin lesions - nodules and plaques Extend peripherally while central areas heal with scarring and atrophy Mucosal lesions extend to and destroy the nasal cartilage Cardiovascular disease Neurosyphilis (general paresis or tabes dorsalis)
64
how to diagnose symphilis?
Clinical findings Serology Strong index of suspicion required in 2ndary syphilis
65
How to treat syphilis?
IM benzylpenicillin or oral tetracycline
66
Leprosy cause?
Mycobacterium leprae
67
features of Lepromatous leprosy
Multiple lesions: macules, papules, nodules - Sensation and sweating normal (early on)
68
features of Tuberculoid leprosy
Solitary or few: elevated borders – atrophic center, sometimes annular - Hairless, anhidrotic, numb
69
how can cutaneous TB be acquired?
- Exogenously (primary-inoculation TB and tuberculosis verrucosa cutis) - Contiguous endogenous spread – (scrofuloderma )or autoinoculation – periorificial tuberculosis - Haematogenous/lymphatic endogenous spread –dissemination (lupus vulgaris, miliary tuberculosis, gummas)
70
investigations TB
- Interferon-γ release assay (Quantiferon-TB) - Histology – ZN stain - Culture / PCR
71
TB cutaneous manifestations
Tuberculous chancre - painless, firm, reddish-brown papulonodule that forms an ulcer Tuberculosis verrucosa cutis - wart-like papule that evolves to form redbrown plaque Scrofuloderma – subcutaneous nodule with necrotic material - becomes fluctuant and drains, with ulceration and sinus tract formation. Orificial TB - non-healing ulcer of the nasal mucosa that is painful Lupus vulgaris – red brown plaque - +/- central scarring, ulceration Miliary TB - pinhead-sized, bluish-red papules capped by minute vesicles Tuberculous gumma – firm subcutaneous nodule - later ulcerates
72
Molluscum Contagiosum common in who?
children + immunocomprmised
73
Molluscum Contagiosum cure?
Usually resolve spontaneously
74
Herpes Simplex Virus: HSV-1 infection?
direct contact with contaminated saliva / other infected secretions
75
Herpes Simplex Virus: HSV-2 infection?
sexual contact
76
how does herpes simplex travel?
Travels by retrograde axonal flow to dorsal root ganglia
77
What type of eczma can result of herpes simplex virus?
Eczema herpeticum emergency Monomorphic, punched out erosions (excoriated vesicles)
78
Herpes gladiatorum risk factor
Contact sports e.g. wrestling | HSV 1 involvement of cutaneous site reflecting sites of contact with another athlete’s lesions
79
how to treat neonatal herpes simplex virus
Requires IV antivirals Encephalitis → mortality >50% without treatment, 15% with treatment → neurological deficits
80
how to treat herpes simplex virus
Don’t delay Oral valacyclovir or acyclovir 200mg five times daily in immunocompetent localised infection Intravenous 10mg/kg TDS X 7-19 days
81
Hand foot and mouth disease cause
Coxsackie A16, Echo 71
82
how to treat hand foot and mouth disease
don't - usually self limiting
83
Which viruses cause morbilliform (measles-like) eruptions
Measles, Rubella, EBV, CMV, HHV6 & HHV7 cause morbilliform (measles-like) eruptions Leptospirosis Rickettsia
84
Erythema Infectiosum cause
Parvovirus B19
85
causes of Roseola infantum
by HHV6 and HHV7 (less commonly)
86
Orf causes
parapoxvirus | -> due to Direct exposure to sheep or goats
87
important superficial fungal infections to know
1. malassezia | 2. Dermatophytes
88
disseminated fungal infection to know
aspergillus
89
Pityriasis versicolor treatment
Topical azole
90
Kerion: what is it?
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
91
Aspergillosis risk factors
: neutropaenia & corticosteroid therapy]-> primarily resp pathogen Propensity to invade blood vessels causing thrombosis and infarction Lesions destructive – may extend into cartilage, bone and fascial planes
92
Mucormycosis cause
Apophysomyces, Mucor, Rhizopus, Absidia, Rhizomucor Treatment consists of aggressive debridement and antifungal therapy Culture positive in only 30% of cases
93
Scabies cause
Sarcoptes species Female mates, burrows into upper epidermis, lays her eggs and dies after one month. Insidious onset of red to flesh-coloured pruritic papules Affects interdigital areas of digits, volar wrists, axillary areas, genitalia
94
diagnosis of scabies
- diagnostic burrow of fine white scales often seen
95
treatment of scabies
permethrin, oral ivermectin | - Two cycles of treatment are required
96
treating head lice
malathion, permethrin, or oral ivermectin
97
treating body lice
thorough cleaning or discarding clothes
98
treating Pubic Lice
malathion / permethrin, oral ivermectin
99
treating bed bugs
fumigation of homes
100
What are symptoms of scarlet fever and how does it present?
Preceded by sore throat, headache, malaise, chills, anorexia and fever Eruption begins 12-48 hrs later:

BRS Year 2 (110 decks)

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