Infections and Infestations Flashcards
Describe change on skin of newborn baby in first few days of life?
Baby goes from sterile womb environment to non-sterile world.
Skin is colonised by 1000s of bacteria
Baby commonly gets rash called Pitorosporum
What are some common bacteria and funghi that normally live on our skin?
Staph Aureus
Staph Epidermis
Candida
Common signs of infection?
Remember classic signs
Rubor (Redness)
Dolor (Pain)
Calor (Heat)
Tumour (Swelling)
Pus
Blisters etc
How do you diagnose infection?
History
Exam
Investigations
What are some common investigations?
Swabs
Bloods (LFTs, U&Es etc)
Biopsy
What are the common infective agents of the skin?
Staph Aureus
Strep Pyogenes
What are the 4 bacterial infections to note?
Impetigo
Cellulitis
Oedema Blisters
Lipodermatosclerosis
What is Impetigo?
Most common bacterial infection in children
Honey crusted scabs (may also have Bulla) which are made worse by scratching
Caused by Staph Aureus and Strep Pyogenes
How do you treat Impitigo?
Topically -
Fusidic Acid 3/4 times a day for 5 days
Mupirocin 3/4 times a day for 5 days (if MRSA)
Orally (if systemic, severe or bullous) -
Flucloxacillin - 4x times daily for 7 days
Erythromycin - 4x times daily for 7 days
What is Cellulitis?
Bacterial infection caused by Staph Aureus and Strep Pyogenes
Causes red swollen lower limbs, may be hot
Where is cellulitis common?
Lower limb - below the knee
What are the symptoms of cellulitis?
Tender and hot
If the infection is extensive then fever as well
How do you diagnose Cellulitis?
Take swab and send to lab
Start on empirical Abx
IV Flucloxacillin every 6 hours
AND Benzylpenicillin every 6 hours
Review Abx after 48 hours and check bacterial swab results
If the Cellulitis isnt better in a week what might have happened?
Diagnosis wrong - think of differential diagnosis eg
Necrotising Fasciitis
Venous Eczema
DVT
Allergic Dermatitis
What is Ersypelas?
Acute, sometimes recurrent disease caused by a bacterial infection, characterized by large raised red patches on the skin.
More superficial than cellulitis
Caused by strep
Skin is raised and inflamed over infected area
What are Oedema Blisters?
Exacerbation of Oedema
Can be misdiagnosed as Cellulitis as affects lower limbs and dorsum of feet
Causes redness and swelling
What causes Lipodermatosclerosis?
Poor circulation in lower limbs causes inflammation of fat
Often hints at underlying venous issues
How do you treat Lipodermatosclerosis?
Compression stocking
Treat underlying venous disease or refer to specialist
Topical Steroids for inflamm
Name 2 common forms of Fungal infection
Tinea (Moulds) - Dermatophyte
Candidiasis (Yeasts) - red circles
Name some Tinea infections based on body area affected?
Tinea Corporis - Body (Ringworm)
Tinea Capitis - Head/Scalp
Tinea Cruris - Groin
Tinea Pedis - Foot
How do you diagnose fungal infections?
Skin scraping, hair or nail sample
Incubate in lab - results can take weeks
How do you treat tinea of scalp and nails?
Oral antifungals
How do you treat Tinea of the body, hands, feet etc? (NOT scalp and nails)
Topical antifungals eg
Clotrimazole
Terbinafine
What are the best agents to treat tinea pedis (dermatophyte fungi)?
Clotrimazole or terbinafine
What happens when you use topical steroids on tinea?
Loss of scaly appearance
(tinea incognita)
Who else besides the patient do you need to treat if Tinea infection is present?
Family and close contacts
What common condition is Tinea sometimes mistaken for?
Eczema
What is the most common yeast infection?
Candida albicans- grows on moist areas
(obese people who are unable to wash well)
What is Candida Albicans?
Common yeast infection - likes warm, moist environments
What does candida albicans look like?
Brick red erythema
Satellite pustules
(commonly foound underneath the breasts or inbetween the fingers of people who have a lot of wetness on their hands - occupation related)
How do you treat Candida Albicans?
Topical antifungal eg
Miconazole
Ketoconazole
ZOLES
What is Intertrigo and how is it linked to fungal infections?
Intertrigo is inflamm of skin folds eg areas where skin may rub more (under breasts etc)
This inflamm can be made worse by bacterial or fungal infections eg Candida Albicans commonly (warm and moist)
What are some common viral infections you may see?
Viral Warts
DNA Pox Virus
Herpes Simplex Virus
Herpes Zoster Virus
Describe Viral Warts
Common in children, often on hands
Resolve usually on their own within few years
Shouldnt limit child - plaster over them
If persist can freeze off
Describe DNA Pox Virus
Papules with a central dent
Treat with 5% Potassium Hydroxide to papule - body will launch immune response and then recognise from then on
Describe Herpes Simplex Virus
Type 1 = Coldsores
Type 2 = Genital Warts
Treat with Aciclovir
What is the pathogenesis of the herpes simplex virus?
Primary infection
Latent period
Reactivation
Who is likely to suffer from worse cinical episodes from the herpes simplex virus?
The immunosuppressed
Those with atopic eczema
Describe the Herpes Zoster Virus
Chickenpox in children - usually build immunity to it
Can reactivate in adults as SHINGLES
Very harmful to others who havent had pox before so IPC measures very important
What is the pathogenesis of the herpes zoster virus?
Primary exposure
Chicken pox
Latent infection
Reactivation
Shingles
(pain / constitutional symptoms)
about 4 days after - rash
The rash usually tracks around the body - however it does not cross the midline of the body
Name a common INFESTATION
Scabies
What is the main symptoms in scabies?
Itching - may also see red raised bumps which hints at burrows
What causes the itching in scabies?
A protein in mite droppings
Where does scabies normally infect?
Hands & Feet
Also areas of body hair eg genitals, breasts, belly button etc
How is scabies spread?
Long skin-skin contact (about a minute), also bed sheets, clothing etc
What causes the rash associated with scabies, describe the rash
Allergic rash is usually on the sides of the torso – lesions here do not have mites – they are the allergic manifestation of the mites
How do we diagnose Scabies?
A) Skin scraping/swab and send to lab
B) Also useful to draw circle in ink around suspected burrow and wipe away ink - if some doesnt budge its because ink has entered the burrow
How do we treat scabies?
PERMETHRIN CREAM - applied head to toe for 8 hours
Do again 7 days later
Also treat family/close contacts - wash bedding etc
Treat ongoing itch symptomatically with steroids for anti-inflammatory effects.
