Antimicrobial therapies for

skin, soft tissue and

mucosal infections

Caroline ChenAntimicrobial Pharmacist

National Centre for Antimicrobial Stewardship

Outline

• Skin

– Topical antifungals

• Combination antifungal-corticosteroid products

– Topical antibacterials

• Anti-staphylococcal antibiotic creams

• Metronidazole cream

• Scabies treatment

• Eye– Bacterial conjunctivitis and role of ocular antibiotics

• Mouth– Topical treatments for oral thrush

• Useful resources

Topical antifungals

for the skin

General considerations

• Reduce moisture as much as possible– Wear loose fitting clothing with natural fibres (e.g cotton)

– Infected areas should be completely dried before covering with clothing

– Avoid occlusive dressing over the area

• Be mindful of patients with poorly controlled diabetes

• Generally, topical therapy is safe, effective and very well tolerated– No robust evidence to suggest development of resistance from topical antifungal therapy

• Oral therapy may be required for extensive or persistent disease

Azole antifungals

• Clotrimazole, bifonazole, econazole, ketoconazole, miconazole

• Used superficial skin fungal infections e.g. tinea, dandruff

• Apply to the affected skin and surrounding area – pay particular

attention to skin folds

• Must be used regularly (3-4 times per day) and continue

treatment for 2 weeks after the symptoms have resolved– Not to be used “PRN”

• Clotrimazole (Canesten®) and micronazole (Daktarin®,

Resolve®) are available as liquids, but contains alcohol

• Also available as a foaming liquid, powder and shampoo

Combination antifungal + cortisone

• Hydrozole® (clotrimazole and hydrocortisone), Resolve Plus® (Miconazole

and hydrocortisone)

• Cortisone provides symptomatic relief of early inflammation

BUT

• Dosing intervals are different for the two components

• Prolonged use of the steroid can lead to real problems

– thinning of the skin

– Tinea incognita: physical appearance of tinea is altered by the cortisone

original infection slowly spreads and is misdiagnosed as dermatitis vicious

cycle

– May encourage growth of resistant fungi

• Use until the inflammation subsides, then continue with clotrimazole alone

Other skin antifungals

• Nystatin (Mycostatin®), terbinafine (Lamisil®), amorolfine

(Loceryl®), ciclopirox (Rejuvenail®), tolnaftate (Tinaderm®)

• Terbinafine (Lamisil®)

– Apply 1-2 times per day

– Available as cream and gel

– Gel contains alcohol so not good for broken skin

– Also available in a “once” only application gel (contains

alcohol)

• Some available as powders – may help to promote dryness, but

powder may clump together and be further irritating on the skin

Is there a difference between

various topical antifungal?

• No real difference in terms of cure at the end of treatment

• Terbinafine (Lamisil) seems to be better in terms of sustained cure

• Most common reasons for failure are poor adherence to treatment,

misdiagnosis, reinfection, drug resistance and infection with an

uncommon species

Topical antibiotics for

the skin

Topical antibacterials for skin• Mupirocin (Bactroban®), fusidic acid (Fucidin®)

• Theoretically, may enable targeted delivery of a high concentration to

the site of infection and less potential for systemic side effects

• Clinically, mainly used for anti staphylococcal activity

• Fairly good evidence for use in impetigo with a small surface area

and nasal decolonisation of S aureus

• Limited clinical evidence for other conditions including prevention

and treatment of chronic wound infections.

• Population-based studies show a very strong association between

use and development of resistance (e.g. New Zealand and WA)

Topical antibacterials for skin

• Metronidazole (Rozex®)

– Indicated for rosacea and also malodorous fungating wounds

– Reduce unpleasant odour of fungating wounds – may need prolonged treatment

as odour usually returns after treatment is stopped

Scabies treatments

• Permethrin (Lyclear®)

• Also used for head lice and public lice

• Extremely effective and low toxicity, generally very well tolerated

• May temporarily increase the itch, redness and swelling normally associated

with lice or mite infestations

• Apply everywhere! Scalp, neck, face, ears and body. Don’t forget about belly

button, between fingers and toes, under nails, between skin folds, between

buttocks and to groin area

• Apply at night and leave on for 8-14 hours. Wash off with warm water and

rinse thoroughly

• You will need to use almost the entire tube for one application

Scabies

• Requires 2 applications, 7 days apart

• Itch can last 2-3 weeks don’t mistake this for ongoing infection

(but needs further investigation if it persists beyond 4 weeks after

completing treatment)

• Need to treat all contacts

• Wash all bedding, clothing and towels that have been in contact with

the affected person in the last 72 hours in hot water the morning

after each application OR store them in a tightly sealed plastic bag

for at least 3 days

• DOH guidelines for managing outbreaks

Other general tips for skin products

• Don’t mix all the creams together – active ingredients may be inactivated

and the formulation itself may split

• Don’t apply creams where transdermal patches need to be applied

• When using different topical products (including moisturisers), allow

sufficient time (eg 10–15 minutes) for absorption between applications; it is

not clear which to apply first

• If you are using a tub-based product (e.g. emollients), throw it away once

the infection has resolved to avoid the risk of ongoing contamination and re-

infection

– Avoid using fingers – use a spoon, spatula etc

Ocular (eye)

antibiotics

Eye products

• Various eye products available to treat bacterial eye infections

• OTC – chloramphenicol (Chlorsig®), propamidine (Brolene®)

• Prescription – ciprofloxacin (Ciloquin®), gentamicin (Genoptic®), tobramycin

(Tobrex®), framycetin (Soframycin®) etc

• Bacterial conjunctivitis

– self-limiting condition and resolves in a few days

– topical antibacterials are used to speed up recovery and prevent spread to others

– Only use if the infection is likely to be caused by bacteria – rapid onset,

mucopurulent discharge. Not for just a ‘red eye’

– Viral conjunctivitis does not require antivirals or antibacterials – watery discharge,

recent URTI

Chloramphenicol (Chlorsig®)

• Available as drops or ointment

• Drops are easier to apply and more “comfortable” however

shorter acting

• Ointment may be messy but longer lasting

• Usually some stinging or burning sensation after application

and will be able to taste it in the back of the throat

• Drops: apply 1 drop every 2 hours while awake for the first 1-2

days. Once there is improvement, can reduce to 1 drop 4

times a day for up to 5 days.

• Ointment: use at night, or can be used during the day as a

single agent 3-4 times a day

Antifungals for the

mouth

Treatment of oral candidiasis

• Miconazole (Daktarin®) oral gel, nystatin (Nilstat®) drops,

amphotericin (Fungilin®) lozenges

• Use after a meal or drink. Keep it in their mouth for as

long as possible before swallowing

• Usually applied 4 times a day for 7-14 days and

continue for several days after symptoms resolve

Treatment of oral candidiasis

• Daktarin oral gel

– Little systemic absorption occurs

– However do still need to be careful with drug interactions e.g. warfarin

– If giving it to someone who can’t swallow properly, be careful to apply it

at the front of the mouth in small amounts so that they don’t choke

– If using for oral candidiasis associated with dentures, apply to the

dentures after cleaning and leave on overnight

Resources

• Australian Medicines Handbook (AMH)

– Excellent reference with practical administration tips

• AMH Aged Care Companion

• Therapeutic Guidelines

– If using paper version, note that some recommendations are in

the Dermatology book

• MIMS

– Manufacturer’s product information

– Some dosing information sub-optimal

– Useful for detailed information on PK/PD and administration

Summary

• Topical antifungal creams are well tolerated, but require regular application

for at least 2 weeks to be effective

– PRN use is pointless

• Avoid combination antifungal + corticosteroid products

• Topical antibiotic creams like Bactroban and Fucidin have a very limited role

in therapy

– Big problems with resistance developing in S aureus

• Chlorsig eye drops should be used for bacterial conjunctivitis (not just for a

“red eye”)

• When treating oral thrush, be careful of drug interactions when patients are

on topical oral products