Skin infections and infestations Flashcards
What is an infection
Invasion and multiplication of a disease causing organism which leads to cellular injury
What is the normal skin flora
aerobic cocci:
Staphylococcus epidermis
staphylococcus aureus
Corynebacterium and propionbacterium
yeasts - malassezia furfur
What are the signs of an infection
erythema
hot
tender
pus
exudate
fever
What investigations are done for skin infections
Microscopy, culture and sensitivities
What does a bilateral rash normally eliminate from possible diagnosis
Infection
What is impetigo
Superficial skin infection which does not go deeper than the epidermis
It is the most common bacteria skin infection in children
What are the common pathogens which cause impetigo
Staph aureus is the most common
Strep pyogenes is also common
What is the classical sign that is diagnostic of impetigo
Golden crust
What is the treatment of impetigo
If localised : furisidic acid 3-4 times a day for 5 days
if MRSA give mupirocin
If widespread or severe or bullous -
Oral flucloxacillin 500mg 4x a day
erythromycin oral 500 mg 4x a day
What is the common presentation of cellulitis and erysipelas
Asymmetrical with an acute history
What is the common causative bacteria of cellulitis and erysipelas
erysipelas and cellulitis - strep pyogenes is most common and then staph aureus
What is the treatment for cellulitis and erysipelas
Only if severe:
Flucloxacillin IV 1g every 6 hours
If there is no response add benzylpenicillin iV 1.8g every 6 hours
What is the presentation of necrotising fasciitis
Patient appears very unwell and in pain - when undergoing a CT will see gas bubbles at the infection site
What is the management if bacterial infection of the skin
Take a swab and begin antibiotics since the swab takes time to come back
Adjust the treatment after the swab to what the diagnosed bacteria is vulnerable to and then review in a week
What is the presentation of oedema blisters
Acute exacerbation of oedema
Commonly on dorsum of the feet
often erythematous - red
can feel hot
What is the management of oedema blisters
Drainage of fluid and sending sample for blood test
Doesn’t need antibiotics if systemically well
What is lipodermatosclerosis
Inflammatory issue of the leg which is characterised by subcutaneous fibrosis and skin hardening
Who is lipodermatosclerosis more commonly seen in
Older people with venous issues
What are common signs of lipodermatosclerosis
Signs of venous disease and often bilateral
What is the treatment of lipodermatosclerosis
Treat the underlying venous issue and give topical steroids
Are fungal infections symmetric or asymmetric
asymmetric
What is the treatment for tinea
Tinea on the feet, body, hands or groin respond to topical treatment : Terbinafine or clotrimazole cream
Scalp or nails will respond to oral antifungals
What are the differences between eczema and tinea
Eczema is symmetrical while tinea is asymmetric
Eczema is commonly found on the flexors
What are the common places to get yeast infections
Skin folds
What is the treatment for candida
Antifungals - ketoconazole, nystatin and miconazole
What is intertrigo and what is treatment
Superficial inflammatory condition Secondary to friction and irritating effect of sweat on the flexors
Emollients to reduce friction will help
What can be seen in human papilloma virus
Hand and finger warts
Can see black dots on microscopy which are thrombosed capillaries
What is the treatment of warts
Not necessary usually
Wart paints and cryotherapy can stimulate the immune system to attack the warts
When do warts go away
When the patient develops immunity against the wart virus
Why is it hard to clear viral warts
They affect the outer layers of skin so the immune system is not really aware of them
How does cryotherapy work
Liquid nitrogen which causes medical frost bite and inflammation, alerts the immune system to the area
What is molluscum contagiosum
DNA pox virus
papules
resolves when immunity develops
Highly contagious
What is the treatment of molluscum contagiosum
Potassium hydroxide can be used which causes inflammation which alerts the immune system to the presence
What does herpes simplex 1 cause
Cold sores
What does herpes simplex 2 affect
The genitals
What is the treatment of herpes simplex 1 and 2
Acyclovir
What is herpes zoster virus
Chicken pox in children
Shingles in adults - is the same virus as chicken pox which stays dormant until the immunity of the individual decreases
What is the treatment for scabies
Permethrin cream all over for 8 hours 2 applications of 30g a week apart
Shouldbe done to people who were in close contact as well
Oral IV ivermectin can be used but not in the UK and needs 2 dosage
How does permethrin work
It is antiparasitic so it kills the mites as well as the eggs
Why does the itch from scabies take time to go after the treatment
The burrows were present for so long that it takes time for the itch to decrease
What is the presentation of shingles
Pain or tingly sensation before the rash is visible - the rash affects dermatomes so it is asymettrical (on one side) and is a horizontal line like a dermatome
patient is usually immunocompromised which reactivates the herpes zoster virus
