Topical antibiotics: very few indications for use

1. Not all patients with a skin infection require an antibiotic (Table 1)
2. If an antibiotic is required, topical antibiotics are only appropriate for patients with minor, localised areas of impetigo

Most minor skin infections are self-limiting and resolve without the use of an antibiotic (with standard skin hygiene advice). The decision to treat will be determined by several factors, including the extent and severity of infection, the patient’s co-morbidities and socioeconomic status (e.g. living environment).

Despite increasing bacterial resistance to fusidic acid, it remains a valid treatment option for patients with localised areas of impetigo caused by Staphylococcus aureus, Streptococcus pyogenes or other related streptococci.² Oral antibiotics are appropriate for patients with more extensive areas of infection or systemic symptoms. Fusidic acid may also be considered for treating patients with small, localised areas of infected eczema, however, oral antibiotics are more likely to be required as infected eczema is often extensive.

Topical mupirocin should be reserved for treating patients with localised mild skin infections (impetigo or infected eczema), that are resistant to fusidic acid and have sensitivity to mupirocin.

Table 1: General guidance for use of antibiotics for skin infections most commonly seen in general practice¹

Antibiotic management of impetigo

Topical treatment with fusidic acid may be considered for a patient with no more than three areas of impetigo or an area of infection of less than 5 cm² .² Response to treatment should be regularly assessed, and a switch to oral antibiotics considered if the infection is not resolving or is worsening. A swab for culture and sensitivity will help to guide treatment in this case.

Advise the patient/carer to remove crusted areas on lesions, with warm water and a soft, clean cloth.³ Apply fusidic acid 2% ointment or cream to lesions three times daily, for seven days.^{1, 2}

Oral antibiotics are more appropriate than topical treatment for patients with widespread lesions or if systemic symptoms are present. The recommended oral antibiotic treatment is flucloxacillin:¹

• Child – 12.5 mg/kg/dose, four times daily,* for five to seven days
• Adult – 500 mg, four times daily, for five to seven days

* If compliance is an issue, an alternative regimen is flucloxacillin 10 – 25 mg/kg/dose, three times daily (maximum 500 mg per dose) for five to seven days.² To optimise absorption, oral flucloxacillin is ideally taken on an empty stomach.

Cephalexin has been recommended as an option for children who find flucloxacillin syrup unpalatable,² however, consideration should be given to the disadvantages of using an unnecessarily broad spectrum antibiotic and the effect on the spread of antimicrobial resistance. Erythromycin is an alternative for patients with penicillin allergy. If MRSA is found to be present, the recommended treatment is oral co-trimoxazole (see: New Zealand Formulary or the bpac^nz antibiotic guide for recommended doses of these medicines).

In children with impetigo, the affected area should be kept covered and the child excluded from day-care or school until 24 hours after antibiotic treatment has been initiated.³

Information and resources for families about impetigo are available from: www.kidshealth.org.nz/impetigo-school-sores

Antibiotic management of infected eczema

A topical antibiotic may be considered for patients with a small area of infected eczema (a single patch < 5 cm² ), that is not resolving with usual eczema management (including antiseptic baths).^{4, 5} Advise the patient/carer to apply fusidic acid 2% ointment or cream to the infected area three times daily, for seven days. A combination fusidic acid/corticosteroid product is also an option.

Oral antibiotics are appropriate when the infection is more widespread (i.e. > 5 cm² ), if there is more than one area of infection or if systemic symptoms occur.⁵ The same oral antibiotic regimen as recommended for impetigo can be used.

Where possible, topical emollients and medicines should be provided in a tube or pump dispenser to reduce the risk of contamination. Emollients in a tub should be scooped out for application to skin using a spoon or ice-cream stick. After an infection patients/carers should be advised to discard and renew topical medicines in tubs, as they may have become contaminated.^{4, 5}

Recurrently infected eczema is usually due to under-treatment of the eczema. Factors such as adherence should be addressed, and a referral made to dermatology if eczema persists despite primary care intervention.

Combination topical antibiotic + corticosteroid

Several topical combination antimicrobial/corticosteroid products are available in New Zealand. Fusidic acid is combined with betamethasone in Fucicort (partly subsidised). Pimafucort contains hydrocortisone, natamycin and neomycin (fully subsidised).⁶

These products are best reserved for treating small areas of localised infection in patients with an underlying inflammatory skin condition that will respond to a corticosteroid.⁶ For example, Fucicort may be considered for a patient with a small area of eczema (in which a corticosteroid is part of the treatment regimen) with a secondary bacterial infection (for which fusidic acid may be appropriate). Pimafucort may, for example, be considered for the treatment of a patient with superficial skin lesions that will respond to corticosteroids, complicated by a secondary candidal infection.⁶

It is recommended that these combination products are used regularly, for a short time period, e.g. twice daily, for seven days.⁶

Fucicort and Pimafucort are not appropriate for the treatment of acne vulgaris. Topical antibiotics (e.g. clindamycin, erythromycin) are no longer funded for the treatment of acne but may be used for patients with mild inflammatory acne which does not respond to topical retinoids or where topical retinoids are not tolerated.⁷

S. aureus skin infections in New Zealand have increased significantly over the past decade.¹¹ More people are being hospitalised with skin infections, and there is an increase in the number of infections being reported in the community.¹¹ The incidence rate of patients hospitalised with S. aureus skin infections in the Auckland DHB region increased from 81 cases per 100 000 people in 2000 to 140 cases per 100 000 people in 2011, which represents an increase of approximately 5% per year.¹¹ Māori and Pacific peoples, adults aged over 75 years, children aged under five years and people living in more deprived areas have been found to have a higher incidence of hospitalisation for S. aureus infection.¹¹ Factors contributing to the high rates of S. aureus infections in New Zealand are thought to include delayed access to health care, increasing overcrowding in households and declining socioeconomic circumstances in some population groups.¹¹

With the high rates of S. aureus skin infections in New Zealand and the increasing emergence of resistant strains, it is important that measures are put in place to reduce the risk of recurrent infections, especially among households. This primarily involves educating patients and their families about infection control measures and the principles of good hygiene. A formal decolonisation regimen, using topical antibiotic and antiseptic techniques, is not necessary for all patients, but may be appropriate for those with recurrent staphylococcal abscesses.

General messages for preventing skin infections

General lifestyle and hygiene measures can be discussed with families to reduce the likelihood of skin infections.

These include:¹⁷

• Use an emollient to treat dry skin
• Ensure that skin conditions such as dermatitis or eczema are optimally managed
• If skin is dry or damaged, avoid soaps which can irritate the skin, and prolonged exposure to hot water
• Where possible, store and use skin products from pump or pour bottles, rather than jars
• Keep fingernails and toenails trimmed and clean
• Do not share personal hygiene items such as hairbrushes, razors, facecloths and towels, and regularly clean these items
• Wash and dry hands after using the toilet and before eating
• Wash clothes, towels and sheets regularly; if a family member has a skin infection, ideally use hot water and dry items in a hot clothes dryer (although acknowledging that this is often not affordable for families). A hot iron can be used after clothes are dry.
• Regularly wash toys using a mild disinfectant – hard toys can be washed in a dishwasher, soak soft toys prior to washing; there is no evidence that freezing soft toys reduces bacterial contamination¹⁸
• If a skin injury occurs, clean and cover it to help prevent infection and regularly change the dressing
• Avoid scratching skin lesions
• Avoid sharing bath/cleaning water when a member of the family has a skin infection
• Avoid swimming in unclean/untreated water if an open wound is present

Information for families is available from: www.health.govt.nz/system/files/documents/publications/looking-after-your-childs-skin-treating-skin-infections-guide-parents-caregivers-nov-13.pdf

Decolonisation of S. aureus in patients with recurrent abscesses

Patients presenting in primary care with recurrent staphylococcal abscesses (furuncles or carbuncles) are likely to be carrying a high bacterial load of S. aureus (some with MRSA), which is causing multiple re-infections when skin becomes damaged, e.g. through scratching or injury. The most common site of staphylococcal colonisation is inside the nostrils. Other frequently colonised sites include the groin, perineum, axillae and pharynx. There is conflicting evidence as to whether undergoing staphylococcal decolonisation results in fewer skin infections (see: “Evidence of effectiveness of decolonisation measures”. However, if a patient with recurrent staphylococcal abscesses (or their parents/carers) is likely to be compliant with a decolonisation regimen, it is reasonable to try this. Treatment to eliminate S. aureus colonisation in the most affected member of the household is usually all that is required to prevent recurrences in all household members.

Decolonisation should only begin after acute infection has been treated and has resolved.

The first step is to take a nasal swab to determine whether the patient has S. aureus nasal colonisation and if so, whether the S. aureus colonising the patient is sensitive to fusidic acid or mupirocin:

• If S. aureus is present and the isolate is sensitive to fusidic acid the patient should be treated with fusidic acid 2% cream or ointment, applied inside each nostril (with a cotton bud or finger), twice daily, for five days.
• If S. aureus is present and the isolate is resistant to fusidic acid, but sensitive to mupirocin, the same treatment regimen should be undertaken, but with mupirocin 2% ointment.
• If S. aureus is not present or if the isolate is resistant to both fusidic acid and mupirocin, topical treatment is not indicated. Systemic antibiotics may be required in some patients with particularly resistant strains of S. aureus;¹⁷ discuss this with an infectious diseases specialist.

Bleach baths or antiseptic washes should also be used

To help reduce the bacterial load, patients undergoing S. aureus decolonisation should also be advised to shower or bathe for one week using an antiseptic.

For a bleach bath, add 1 mL of plain unscented 5% bleach per 1 L of bathwater (or 2 mL of 2.2% bleach per 1 L of water). Products that contain added detergent (e.g. Janola) are not recommended. N.B. A regular-sized bath filled to a depth of 10 cm contains approximately 80 L of water and a baby’s bath holds approximately 15 L of water.¹⁹

After immersing in the bath water for 10 – 15 minutes, rinse with fresh water. The bleach bath should be repeated two to three times within the week.

A patient/carer handout on instructions for a bleach bath is available from: www.kidshealth.org.nz/sites/kidshealth/files/pdfs/bleach_bath_handout.pdf

Alternatively, patients may shower daily for one week, using triclosan 1% or chlorhexidine 4% wash. The wash can be applied with a clean cloth, particularly focusing on the axillae, groin and perineum. Although difficult in a showering situation, the antiseptic should ideally be left on the skin for at least five minutes before being rinsed off. Hair can be washed with the antiseptic also.¹⁷

Bleach baths or antiseptic washing can be carried out intermittently after the initial decolonisation period, to help prevent recurrence of infection.¹⁷ This can also be recommended for patients with recurrent skin infections who have not undergone formal decolonisation.¹⁷

Mouth gargle

As S. aureus can also colonise the pharynx, an antiseptic throat gargle (e.g. chlorhexidine 0.2% solution, three times daily) is also recommended for the duration of formal decolonisation treatment.¹⁷

Linen and clothing can also be decolonised

To support the decolonisation regimen, potentially contaminated clothing, towels, facecloths, sheets and other linen in the household should be washed then dried on a hot cycle in a clothes dryer, or dried then ironed. Clothing and linen that is white or colourfast can be washed with diluted household bleach. Washing is recommended twice within the one week decolonisation period.¹⁷

Ideally, the household should also replace toothbrushes, razors, roll-on deodorants and skin products. Hair brushes, combs, nail files, nail clippers can be washed in hot water or a dishwasher.¹⁷

Surfaces that are touched frequently, such as door handles, toilet seats and taps, should be wiped daily, using a disinfectant, e.g. alcohol wipes, bleach.¹⁷

Soft furnishings that cannot easily be cleaned, e.g. couches and arm chairs, can be covered in a sheet or blanket that is regularly washed.

Antiseptics slow or stop the growth of micro-organisms on external surfaces of the body, i.e. the skin and mucus membranes, and help to prevent infections.²² Antiseptics have broad-spectrum bactericidal activity and can also act against fungi, viruses and protozoa.²³ There has been recent interest in the use of antiseptics for treating skin infections, to help to reduce the use of topical antibiotics. Antiseptics contribute to bacterial resistance to some degree, but not to the extent that antibiotics do. This is because antiseptics generally eliminate or inhibit all bacteria, whereas antibiotics act only on susceptible bacteria.²³

There is currently a lack of evidence to support the use of topical antiseptics in the treatment of minor skin infections. However, they do have a role in preventing infection in wounds.²⁴ Like topical antibiotics, antiseptics only work on external surfaces of the body and do not have any effect on systemic infections.²²

In general, antiseptics may be used for:²²

• Cleaning cuts, abrasions and other minor injuries to help prevent infection from occurring
• Hand washing to prevent cross-contamination
• Prior to surgical procedures to reduce resident skin flora
• In the prevention of recurrent skin infections to reduce bacterial load on the skin

N.B. Antiseptic solutions can cause irritation or contact dermatitis in some people, and some products may stain the skin.²²

Most antiseptics reduce bacterial load: the clinical significance of this is uncertain

Much of the evidence about antiseptics is in regards to their use in dressings for preventing infection in open wounds rather than as a treatment for minor skin infection.²⁴ Many antiseptics do reduce bacterial load in a wound, but the clinical significance of this is uncertain. Bacterial load is also not the only predictor of infection – other predictors include the presence of foreign bodies in the wound, the patient’s co-morbidities and the virulence of the bacteria present.²³ There is evidence that some antiseptics can be toxic to human cells important in the healing process, e.g. fibroblasts, keratinocytes and leukocytes, however, this is usually only when antiseptics are used at high concentrations.^{23, 24}

Povidone iodine is one of the more frequently used antiseptics. It has been shown to reduce the bacterial load in wounds and not to impede healing, however, there is no evidence that it increases the rate of wound healing.²³

Hydrogen peroxide does not negatively affect wound healing, but it is thought to be ineffective at reducing bacterial count.²³ It may be useful as a chemical debriding agent.²³

Chlorhexidine does not adversely affect wound healing, and is likely to be useful as a rinse, but it is uncertain how effective it is in preventing infection in open wounds.²³

Antiseptics are not usually associated with bacterial resistance

Although there have been isolated reports of bacterial resistance to povidone iodine, the consensus is that iodine-resistant strains of micro-organisms have not yet emerged, after over 150 years of use of iodine-containing antiseptics.²⁵ There have been no reports of bacterial resistance to hydrogen peroxide. Some bacterial resistance has been reported to quaternary ammonium antiseptics (Pseudomonas aeruginosa), chlorhexidine (staphylococci) and triclosan (P. aeruginosa).^{25, 26}

Refer to the New Zealand formulary for available antiseptics and subsidy details