Skin Infections and Infestations Flashcards by Andrew Hay

What lives on our skin?

Aerobic cocci

Staphylococcus epidermis
Staphylococcus aureus

Other aerobic and anaerobic bacteria

Cornebacterium
Propionbacterium

Yeasts
-Malassezia furfur

How well did you know this?

Not at all

Perfectly

What are the signs of an infection?

Erythema
Hot
Tender
Pus
Exudate
Fever

How well did you know this?

Not at all

Perfectly

What is pustulous psoriasis?

Generalised pustular psoriasis is a rare and serious skin disorder that presents with flares of widespread sterile pustules on a background of red and tender skin.

How well did you know this?

Not at all

Perfectly

What are good investigations in dermatology?

Skin swab for microscopy, culture and sensitivities (M, C and S)

Skin biopsy

Scrapes of skin

How well did you know this?

Not at all

Perfectly

What is Impetigo?

Impetigo is a contagious superficial skin infection

Most common bacterial skin infection in children

Classical golden crusting, honeycomb sort of look

How well did you know this?

Not at all

Perfectly

What are the causes of impetigo?

Staphylococcus aureus

Streptococcus pyogenes

How well did you know this?

Not at all

Perfectly

What is the treatment for localised impetigo?

Fusidic acid 2% cream 3-4 times daily for 5 days

Mupirocin 2% cream up to 3 times daily for 5 days

How well did you know this?

Not at all

Perfectly

Why does the lecturer prefer Mupirocin treatment for impetigo?

Staph aureus gets resistant to Fusidic acid very quickly so better off with mupirocin

How well did you know this?

Not at all

Perfectly

What is the treatment for widespread, severe, bullous impetigo?

Flucloxacin 500mg oral 4 times a day for 7 days

Erythromycin 500mg oral 4 times a day for 7 days

How well did you know this?

Not at all

Perfectly

What is Erysipelas?

Erysipelas is a superficial form of cellulitis, a potentially serious bacterial infection affecting the skin.

Erysipelas affects the upper dermis and extends into the superficial cutaneous lymphatics. It is also known as St. Anthony’s fire, with reference to the intense rash associated with it.

Patient usually systemically unwell

How well did you know this?

Not at all

Perfectly

What are the likely causes of Cellulitis/Erysipelas?

Streptococcus pyogenes

Staphylococcus aureus

How well did you know this?

Not at all

Perfectly

What is the 1st choice antibiotic in cellulitis/ Erysipelas?

Benzylpenicillin 1.8g IV every 6 hours
-Better for streptococci

Flucloxacillin 1g IV every 6 hours plus benzylpenicillin
-If patient is really sick

How well did you know this?

Not at all

Perfectly

What is the differential diagnosis for cellulitis?

Deep vein thrombosis
Venous eczema
Allergic contact dermatitis
Necrotising fasciitis

How well did you know this?

Not at all

Perfectly

What is the general rule for managing bacterial infection?

Take swab

Start antibiotics

Review after around 48hours

Check skin swab result
Switch according to sensitivities

If not better in a week
-consider alternative diagnosis

How well did you know this?

Not at all

Perfectly

What are oedema blisters?

Acute exacerbation of oedema

Occur on dorsum of feet
Often erythematous
Can feel hot

How well did you know this?

Not at all

Perfectly

What is lipodermatosclerosis?

Lipodermatosclerosis refers to a skin change of the lower legs that often occurs in patients who have venous insufficiency. It is a type of panniculitis (inflammation of subcutaneous fat). Two-thirds of affected patients are obese.

How well did you know this?

Not at all

Perfectly

What are the features of legs with lipodermatosclerosis?

Skin induration (hardening)
Increased pigmentation
Swelling
Redness
“Inverted champagne bottle” or “bowling pin” appearance
Lipodermatosclerosis has also been called hypodermitis sclerodermiformis and sclerosing panniculitis.

How well did you know this?

Not at all

Perfectly

If acute what features may lipodermatosclerosis have in addition to its characteristic features?

Hot and tender

Look for signs of venous disease

BILATERAL

How well did you know this?

Not at all

Perfectly

What is the treatment for lipodermatosclerosis?

Treat underlying venous disease

Topical steroids

What is included in fungal infections?

Tinea
-Infection by a dermatophyte

Candidiasis

How can you spot fungal infections?

Classically cause a ringworm appearance

Advancing erythematous ring
Sometimes scaling around the edges
Pretty much fungal until proven otherwise

How are tinea infections named?

Name depends on site affected

Ringworm or Tinea corporis if on body
Tinea capatis (head)
Tinea fasciei (face)
Tinea pedis (Athlete’s foot)
Tinea cruris (groin)
Onychomycosis (nails)

What is the best way to diagnose fungal infections?

Scrape the edge of the infection

Not the middle as all the dead infection will be here (infection moves outward

What is the treatment for tinea?

Tinea infection of feet, body, hands or groin usually responds to topical treatment
-Terbinafine or clotrimazole cream

Tinea infection of scalp or nails requires oral antifungals

Check and treat other family members

What is the better topical tinea treatment?

Terbinafine is much better at killing dermatophytes. If unsure diagnostically clotrimazole is better

What is the difference between eczema and tinea?

History Distribution Skin scrapings Ezcema is extremely common, Tinea corporis or singworm very rare

What yeasts may cause infection

Candida albicans

What kind of conditions do yeast infections like candida albicans like?

Warm, moist places | under folds of fat, vagina etc

What is the treatment for candida infection?

Nystatin -Will kill yeast (not fungi) Miconazole -Will kill yeast and fungi Ketoconazole cream -Will kill yeast and fungi

What is intertigo?

Intertrigo describes a rash in the flexures or body folds, such as behind the ears, in the folds of the neck, axillae, under a protruding abdomen, in the groin, between the buttocks, in the finger webs or toe spaces.

What are the causes of intertigo?

Most cases are secondary to friction and irritating effect of sweat. Can be due to infection or skin condition

What is the treatment for intertigo?

Emollient can often help Best way is to lose weight

What are viral warts?

Warts are very common non-cancerous growths of the skin caused by infection with human papillomavirus (HPV). More than 100 HPV subtypes are known, giving rise to a variety of presentations. A viral wart on the sole of the foot is also called a verruca, and warty lesions are often described as verrucous.

How many HPV actually cause viral warts?

Only really about 4 main types. Usually dont go to lab for diagnosis

What advice should you give physically active patients with warts?

Children with warts should NOT be excluded from physical activities, but should take care to minimise transmission Cover wart with waterproof plaster when swimming

How contagious are warts?

Warts are contagious but the risk of transmission is low.

What is the treatment for warts?

Not normally necessary - Not very effective - Will go away when patient evelops immunity against wart virus Give patient a leaflet on viral warts

What is Molluscum Contagiosum?

Molluscum contagiosum (MC) is a viral infection of the skin or occasionally of the mucous membranes, sometimes called water warts. It is caused by a DNA poxvirus

How may Herpes Simplex Virus (HSV) present in someone immunosupressed or atopic?

Widespread virus symptoms and can be quite ill Eczema herpeticum Treat with aciclovir

What is the pathogenesis of herpes zoster virus?

Same type of behaviour as herpes simplex virus First time your infected -> chicken pox -> tracks up nerve to dorsal root ganglion and stays dormant Sometimes can track down nerve to infect single dermatome -> Shingles

What is Scabies?

Scabies, known as the seven-year itch, is a contagious skin infestation by the mite Sarcoptes scabiei. The most common symptoms are severe itchiness and a pimple-like rash. Occasionally tiny burrows may be seen in the skin.

How long must you have contact with someone to contract scabies?

About 1 min Only caught from people close to you

How do you diagnose scabies?

Finding a burrow is diagnostic

What are good places to find burrows (people to get itchy) in scabies?

``` Nipples Umbilicus Wrists Genitalia Back of ankle Plantar of foot ```

What is the pathogenesis of scabies?

Mite burrows into skin Feces build up and after a couple of weeks reaction occurs -> itching If infected again allergy is already there so symptoms only after a day

What is the treatment for scabies?

Permethrin cream top to toe (literally everywhere) - Leave for 8 hours - Second application a week later - 30g tube for average adult Treat all in household and close contact Explain itch may take 1-4 weeks to settle -treat symptomatically with steroid