Infection And Immunology David Taylor Flashcards
Fungi are carbon heterotrophs. What does this mean?
They require preformed organism compounds as carbon sources
What are fungi? What are they divided into?
Eukaryotic organisms so they have a true nuclei
Divided into yeasts and moulds
What are dermatophytes?
Moulds
Keratinophilic: associated with infections of the skin nails and hair and get spread through direct contact.
Common symptoms include itching burning and pain
What is common in the name of dermatophytes??
Tinea
Eg tinea corporis
Tinea cruris
What is tinea corporis?
Ringworm of the skin
What is tinea cruris?
Ringworm of the groin
What is tinea capitis?
Ringworm of the scalp
Cap= scalp!
Dermatophytes are usually diagnosed visually or by sending nail clippings off for analysis.
What does ring worm look like?
Raised around the edges with a clear area in middle
What is first line treatment for tinea corporis and tinea cruris?
Topical imidazole
Eg clotrimazole, ketoconazole
Should treat with creams for a further two weeks to ensure it goes away
If topical treatment fails, or if someone’s immuno compromised or the infection is particularly wide spread, what can we use to treat tinea corporis and cruris?
Terbinafine ORALLY
250mg a day for 4 weeks
What do we use to treat tinea Capitis? (Ringworm of scalp)
Usually oral treatment is required such as Terbanifine or griseofulvin, PLUS:
Ketoconazole/ selenium sulphide shampoos or terbanafine creams twice weekly
What organisms is griseofulvin effective against?
What about terbinafine?
Griseofulvin effective against Trichophyton tonsurans, microsporum spp.
Terbinafine effective against Trichophyton tonsurans
Griseofulvin is only effective against dermatophytes. Why are long courses needed? Who should avoid it?
Long course as it does not persist in keratinous tissue after the end of therapy
Shouldn’t be taken by people with severe liver disease, and systemic lupus erythematosus
Should be avoided in breast feeding
Avoid in pregnancy and for one month after stopping treatment
What are the main side effects of griseofulvin?
GI side effects
Cognitive effects
Hypersensitivity reactions
Griseofulvin has many interactions. What are these?
Enhances effects of alcohol
Decreases efficacy of oral contraceptives and coumarins
Needs to be taken with or after fatty foods!
What is used first line to treat athletes foot?
Imidazole cream
For 2-4 weeks or
Terbinafine cream for 1 week
Undecenoates for 2-4 weeks
If topical treatment fails for severe athletes foot, what three oral tablets could be taken? (Just say names)
Terbinafine
Itraconazole
Griseofulvin
Terbinafine can be taken orally or topically. It concentrates in keratinous tissue. When should it be avoided? What are the side effects?
Avoid In pregnancy and liver disease. Side effects: GI disturbance Hepatotoxicity with prolonged therapy Serious skin reactions
What species can we commonly find infecting our nails?
Trichophyton rubrum
Epidermiohyton floccosum
Trichophyton mentagrophytes
Onychomycosis means nails. What’s the most common type of nail infection?
DLSO starts at the top of the nail works down to nail bed
What’s a good treatment for fungal nails?
Itraconazole pulse therapy
Itraconazole stays in keratin in nails for longer
Can also use itraconazole 200mg daily for 3 months
Could also use terbinafine for 6 weeks to 3 months
Note this is all SYSTEMIC management, taken orally
We can also use topical treatment for nail infections eg Ticonazole, Amorolfine. When is this appropriate to use?
Topical treatment will only work in mild distal disease in up to 2 nails. White superficial and early DLSO.
Localised distal nail may respond to Ticonazole or amorolfine
What is pityriasis versicolor?
Colonisation of the stratum corneam (in skin)
Caused by malassezia furfur
Starts at the neck and shoulders, multiple dark patches
Starts around puberty
What can we treat pityriasis versicolor with?
Ketoconazole shampoo
Clotrimazole or ketoconazole creams
Terbinafine cream
If these fail Oral treatment: Itraconazole Fluconazole Relapse is COMMON
Why is oral ketoconazole not really used anymore?
Can cause serious and rapid hepatotoxicity
Should only be given under specialist advice
Monitor liver function before and 2-4 weeks after treatment then monthly.
What topical therapy can we give for oropharyngeal candida?
First line: Imidazole antifungals eg miconzaole oral gel for 7 days
Second line: Polyene antifungals such as nystatin suspension 7 days
What oral therapies can be given for oropharyngeal candida?
Fluconazole
50mg daily for 7-14 days
Give it for 14 days if atrophic candidiasis associated with dentures
What fungal organism accounts for 90% of vaginal candidiasis?
Candida albicans
What topical treatments are effective for uncomplicated Vuvovaginal candidiasis?
Clotrimazole,
Econazole
Miconzaole
What oral treatments do we give for vaginal candidiasis?
Fluconazole (150mg single dose)
Itraconazole (200mg twice daily for one day)
What is cutaneous candidiasis and where is it found?
Cutaneous means anywhere that’s wet and moist so is found in folds of the skin, under breast, child’s bum.
It’s a very intense red rash that’s itchy and burny and painful
What can we treat cutaneous candidiasis with?
Topical imidazole
Oral when severe: fluconazole 50mg daily for 14 days
Treat topically in children
What are Arthropods?
Segmented body, appendages, hard exoskeleton made of chitin
What are pediculus humans capitis?
Head lice
What is a nit?
The egg capsule of a head louse
The empty shell that’s left in the hair after a louse has hatched.
Nit does not confirm infestation
What is Dimeticone 4% in a silicone solvent used to treat?
Used for head lice
Physical action but is not a physical insecticide, good for patient who don’t want to use these
Immobilises the lice and disrupts their water regulatory processes
First line!!
What us isopropyl myristate cyclomethicone?
Full marks solution
Has physical action
Disrupts exoskeleton of lice
How is Dimeticone applied?
Applied to dry hair and allowed to dry naturally
Left on for 8 hours then washed off
Reapplication after 7 days
Use with caution in people with asthma and eczema
What causes scabies?
Sarcoptes scabiei
A mite
Burrows into epidermis commonly in flexures/ creases
Papular eruption
Really itchy
Worse at night and after hot bath or shower
Diagnosis through skin scrapings
What is Crusted Norwegian scabies?
A hyper-infestation Whitening of the skin, wet lesion, thick and white. Millions of mites Hyperkeratotic crusts Common in immuno compromised patients Secondary infections can be a problem
Pharamcists should refer if they suspect dermatitis herptiformis. What is this?
Chronic blistering of the skin, blisters fill with watery fluid
Has an appearance similar to herpes but not caused by herpes virus
Symptoms relate to gluten ingestion: gluten allergic
Associated with oral contraceptive use
What should we treat standard scabies with?
Permethrin
Apply it all over the skin but not scalp (but do treat scalp in elderly, immuno-compromised or young)
Leave for 8 hours and wash off
Can be used in 2 months and over, 2month- 2 years must be under medical supervision
Refer if two treatment failures have occurred
A patient has been treated with permethrin for scabies, however three weeks later they’re still feeling itchy. Has treatment failed?
No necessarily, can still itch after eradication
Ease with topical emollients like crotamiton cream 10%.
What’s an alternative first line treatment to permethrin for scabies?
Malathion
Left on for 24 hours
What unlicensed treatment can be used for Norwegian scabies?
Ivermectin
Blocks the neurotransmission action of GABA
What can we treat Itching with in scabies?
Topical crotamiton or topical hydrocortisone
Avoid topical steroids if diagnosis not certain
Sedating antihistamines
What’s the anthropod that causes crab lice?
Pthirus pubis
How is crab lice spread?
Through direct contact, contact with bed clothes
If caught through sexual contact, consider referral to GUM clinic and all their sexual contacts should be screened too
How should we treat crab lice?
Permethrin or malathion
Malathion: suitable for everyone
Permethrin: suitable for all individuals over 18 years old unless pregnant or breast feeding.
Apply these twice with a weeks gap, assess after one week to se if successful.
Should not be used more than once a week and for three consecutive weeks
What’s the itching caused by with headlice?
An immune reaction with saliva
May take time to occur
When to refer headlice?
Treatment failure
Severe infestation
Secondary bacterial infection from itching
Why shouldn’t we use chemical insecticides for nits these days?
Due to resistance
Only use if wet coming and physical insecticide haven’t worked!!
Scabies: finger webs
Dermatitis hypeformis: back and shoulders
Crablice: coarse hair
How can we treat crab lice in the eye lashes?
Simple eye ointment of permethrin or malathion, apply twice a day
How do we treat harvest mite bite?
Hydrocortisone cream and some repellent eg DEET
This is also good for mosquito bites
What’s the disease called that is a risk with tics?
They carry Lymes disease
Refer if tic bite seen
Initially causes fever, at worse affects heart, joints, other organs, potentially paralysis
