Skin infections Flashcards
On clinical examination for skin infection, what signs are you looking for?
- Pustules
- Golden crusting
- Exanthem
- Pyrexia
- Lymphadenopathy
What is a pustule and what might it indicate?
Small elevation of the skin containing cloudy/purulent material (pus) usually consisting of necrotic inflammatory cells
Often indicates infection (viral, bacterial or fungal)
Can be non-infective (psoriasis)
What is golden crusting a sign of?
Could be a manifestation of impetigo
- bacterial skin infection
- usually caused by staphylococcus aureus or streptococcus pyrogenes
What is exanthem?
Acute inflammatory rash that usually occurs in children Usually widespread and symmetrical Often associated with systemic symptoms: - fever - malaise
What kind of infections can exanthem be a sign of? How can you differentiate and diagnose it?
- Parvovirus: slapped cheek look
- Meningococcal meningitis: can perform a ‘glass test’ - if the rash does not blanche then consider this
- -> viral exanthems blanch - Kawasaki disease:
- pyrexia
- lymphadenopathy
- swollen red lips
- palmoplantar erythema
- oedema
- desquamation of fingertips
* this often mistaken for streptococcal infection, however this disease can be FATAL therefore getting the diagnosis right is important
What is fish tank granuloma? What causes it?
- A skin rash that can appear after 3 weeks of being infected
- Caused by mycobacterium that has entered through broken skin
- common in people who clear out fish tanks
- skin biopsy will show granuloma and culture will show mycobacterium marinum
What is Erysipelas?
Acute infection, typically with a skin rash
Erysipelas is more superficial than cellulitis and is typically more raised and demarcated
What is Pityriasis Versicolor?
fungal infection
brown scaly macule (area of skin discolouration) will appear (mainly on trunk and proximal extremities)
the affected area will not tan in the sun
What are erythematous macule on the palms and sole of the feet a sign of? What will show up on blood tests to confirm this diagnosis?
Secondary syphillis
Treponemal antibodies will be detected on blood tests
What is impetigo? How is it treated?
Bacterial infection (staph aureus or strep pyogenes)
Common presentation:
- yellowish crust on face, arms or legs
Uncommon:
- large blisters
- fever
Treatment:
- mupirocin (abx for mild cases)
- dicloxacillin, flucloxacillin or erythromycin (abx for severe cases)
What is cellulitis? How is it treated?
Bacterial infection (streptococci and Staph A)
S+S:
- area of redness which increases in size (over few days)
- borders of redness are not sharp
- skin may be swollen
Treatment:
Antibiotics (such as cephalosporin or cephalexin) and pain relief
What is herpes simplex? How is it treated?
Viral infection caused by HSV
S+S:
- blisters that break open and form small ulcers
- -> affect mouth, genitalia, hands
- fever
- swollen lymph nodes
Treatment: (no method of eradication but can reduce frequency, duration and severity)
- aciclovir (oral/topical)
- valaciclovir (oral)
- docosanol (topical)
What is herpes zoster? How is it treated?
Shingles
Viral disease caused by VZV
Presentation:
- painful rash occurring in a stripe
- may be tingling or pain in same area before rash appears
Treatment:
- analgesics (topical calamine, capsaicin, lidocaine)
- antivirals (aciclovir, valaciclovir, famciclovir)
What is tinea? How is it treated?
Ringworm
Fungal infection
Different kinds of ‘tinea’ depending where on the body the infection occurs, e.g. pedis, corporis, unguium
Presentation:
- red, itchy, scaly, circular rash
- hair loss in affected area
Treatment:
- antifungals (topical miconazole, terbinafine, clotrimazole)
What is scabies?
Contagious skin infestation caused by Sarcoptes scabiei mite
Presentation:
- intense itching (made worse by warmth)
- superficial burrows (linear tracks)
Treatment:
- antihistamines (for itchiness)
- permethrin (insecticide) = most effective treatment
