Antimicrobial therapies for skin, soft tissue and mucosal infections Caroline Chen Antimicrobial Pharmacist National Centre for Antimicrobial Stewardship
Outline Skin Eye Topical antifungals Combination antifungal-corticosteroid products Topical antibacterials Anti-staphylococcal antibiotic creams Metronidazole cream Scabies treatment 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 reinfection 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