The information below is based on NICE NG153 Impetigo: antimicrobial prescribing (February 2020).

Impetigo is a contagious, bacterial infection of the superficial layers of the skin. Impetigo affects all age groups; however, it is most common in young children.

Advise people with impetigo, and their parents or carers if appropriate, about good hygiene measures to reduce the spread of impetigo to other areas of the body and to other people.

Self-care advice:

• Wash affected areas with soap and water
• Wash hands regularly, in particular after touching a patch of impetigo
• Avoid scratching affected areas
• Avoid sharing towels, face cloths, and other personal care products and thoroughly cleanse potentially contaminated toys and play equipment

Initial treatment

Do not offer combination treatment with a topical and oral antibiotic to treat impetigo.

Localised non-bullous impetigo

Consider hydrogen peroxide 1% cream for people with localised non-bullous impetigo who are not systemically unwell or at high risk of complications, if hydrogen peroxide 1% cream is unsuitable, i.e. if ineffective or if impetigo is around eyes, offer a short course of a topical antibiotic (see below for appropriate choices).

Widespread non-bullous impetigo

Offer a short course of a topical or oral antibiotic for people with widespread non‑bullous impetigo who are not systemically unwell or at high risk of complications (see below for appropriate choices).

Bullous impetigo or impetigo in people who are systemically unwell or at high risk of complications

Offer a short course of an oral antibiotic for all people with bullous impetigo, and people with non-bullous impetigo who are systemically unwell or at high risk of complications (see below for appropriate choices).

Further treatment

For people with impetigo that is worsening or has not improved after treatment with hydrogen peroxide 1% cream, offer:

• a short course of a topical antibiotic if the impetigo remains localised or
• a short course of a topical or oral antibiotic if the impetigo has become widespread

For people with impetigo that is worsening or has not improved after completing a course of topical antibiotics:

• offer a short course of an oral antibiotic and
• consider sending a skin swab for microbiological testing

For people with impetigo that is worsening or has not improved after completing a course of oral antibiotics, consider sending a skin swab for microbiological testing

For people with impetigo that recurs frequently:

• send a skin swab for microbiological testing and
• consider taking a nasal swab and starting treatment for decolonisation

If a skin swab has been sent for microbiological testing:

• review the choice of antibiotic when results are available and
• change the antibiotic according to results if symptoms are not improving, using a narrow-spectrum antibiotic if possible

Reassessment and referral

Reassess at any time if symptoms worsen rapidly or significantly, taking account of:

• other possible diagnoses, such as herpes simplex
• any symptoms or signs suggesting a more serious illness or condition, such as cellulitis
• previous antibiotic use, which may have led to resistant bacteria.

Refer to hospital:

• people with impetigo and any symptoms or signs suggesting a more serious illness or condition (for example, cellulitis)
• people with widespread impetigo who are immunocompromised

Consider referral or seeking specialist advice for people with impetigo if they:

• have bullous impetigo, particularly in babies (aged 1 year and under)
• have impetigo that recurs frequently
• are systemically unwell
• are at high risk of complications

Consult local microbiologist if MRSA suspected or confirmed

Antimicrobials for adults aged 18 years and over

A 5‑day course is appropriate for most people with impetigo but can be increased to 7 days based on clinical judgement, depending on the severity and number of lesions.

Topical antiseptic

Hydrogen peroxide 1% cream

• Apply two or three times a day for 5 days

See section 13.11.5 Oxidisers and dyes

Topical antibiotic

Fusidic acid 2% cream/ointment

• Apply three times a day for 5 days

See section 13.10.1 Antibacterial preparations

MRSA infection in impetigo is rare, consult local microbiologist if MRSA suspected or confirmed prior to consideration of topical mupirocin

Oral antibiotic

Flucloxacillin

• 500mg four times a day for 5 days

Oral antibiotic (Penicillin allergy)

Clarithromycin

• 250mg to 500mg twice a day for 5 days
• 500mg twice a day for 5 days if severe infection

Oral antibiotic (Penicillin allergy in pregnancy)

Erythromycin

• 250mg to 500mg four times a day for 5 days
• 500mg four times a day for 5 days if severe infection

See sections 5.1.1 Penicillins and 5.1.5 Macrolides

Antimicrobials for children and young people under 18 years

A 5‑day course is appropriate for most people with impetigo but can be increased to 7 days based on clinical judgement, depending on the severity and number of lesions.

Topical antiseptic

Hydrogen peroxide 1% cream

• Apply two or three times a day for 5 days

See section 13.11.5 Oxidisers and dyes

Topical antibiotic

Fusidic acid 2% cream/ointment

• Apply three times a day for 5 days

See section 13.10.1 Antibacterial preparations

MRSA infection in impetigo is rare, consult local microbiologist if MRSA suspected or confirmed prior to consideration of topical mupirocin

Oral antibiotic

Flucloxacillin

• Children 1 month to 17 years of age (doses given four times a day for 5 days):
  • 1 month to 1 year: 62.5mg to 125mg
  • 2 to 9 years: 125mg to 250mg
  • 10 to 17 years: 250mg to 500mg

Oral antibiotic (Penicillin allergy)

Clarithromycin

• Children 1 month to 11 years of age (doses given twice daily for 5 days):
  • Body-weight under 8 kg: 7.5mg/kg
  • Body-weight 8–11 kg: 62.5mg
  • Body-weight 12–19 kg: 125mg
  • Body-weight 20–29 kg: 187.5mg
  • Body-weight 30–40 kg: 250mg
• Children 12 years to 17 years of age:
  • 250mg to 500mg twice a day for 5 days
  • 500mg twice a day for 5 days if severe infection

Oral antibiotic (Penicillin allergy in pregnancy)

Erythromycin

• Children 8 years to 17 years:
  • 250mg to 500mg four times a day for 5 days
  • 500mg four times a day for 5 days if severe infection

See sections 5.1.1 Penicillins and 5.1.5 Macrolides

Clinical signs of infected eczema include weeping, pustules, crusts, fever and malaise. Also atopic eczema failing to respond to therapy or rapidly worsening atopic eczema. If there are no visible signs of infection use of antibiotics (alone or with steroids) encourages resistance and does not improve healing.

Do not prescribe topical preparations for maintenance therapy.

Take swabs from infected lesions of atopic eczema only if you suspect microorganisms other than Staphylococcus aureus or if you think antibiotic resistance is relevant.

Explain that topical treatments in open containers can be contaminated with microorganisms and act as a source of infection. New supplies should be obtained at the end of treatment for infected atopic eczema.

Extensive bacterial infection

Use oral antibiotics plus appropriate potency topical corticosteroid

If infection responds poorly to antibiotic treatment, consider results of swabs and treat according to sensitivities, or seek specialist advice.

Flucloxacillin

• Adult: 500mg every 6 hours for 7 days
• Child
  • 2–10 years: 125–250mg 4 times daily
  • 10–18 years: 250–500mg 4 times daily

Penicillin-allergy

Doxycycline

• 200mg single dose stat, then 100mg daily for total of 7 days
• Not be used in patients aged under 12 years

3rd line

Clarithromycin

• Adult: 500mg every 12 hours for 7 days
• Child 1 month–12 years:
  • Body-weight under 8 kg 7.5mg/kg twice daily for 7 days
  • Body-weight 8–11 kg 62.5mg twice daily for 7 days
  • Body-weight 12–19 kg 125mg twice daily for 7 days
  • Body-weight 20–29 kg 187.5mg twice daily for 7 days
  • Body-weight 30–40 kg 250mg twice daily for 7 days
• Child 12–18 years 250mg twice daily for 7 days

Localised bacterial infection

Use combined topical antibiotic/corticosteroid preparation for maximum of 2 weeks only.

Do not prescribe topical preparations for maintenance therapy.

Fusidic acid resistance is a widespread problem due to inappropriate use. Swabs should be taken at the same time as prescribing a fusidic acid based product.

Fucidin H® cream (fusidic acid 2% / hydrocortisone 1%)

• Apply twice daily (maximum 14 days)

Fucibet® cream (fusidic acid 2% / betamethasone valerate 0.1%)

• Apply twice daily (maximum 14 days)

For skin flexures and genital area

Trimovate® cream (clobetasone / oxytetracycline / nystatin)

• Apply twice daily (maximum 14 days)

See section 13.4 Topical corticosteroids

Reducing bacterial infections

• Ensure appropriate potency of topical corticosteroid is being used. Inadequate control of the underlying atopic eczema is the most frequent cause of repeated infections.
• Consider antiseptic emollients / shower / bath preparations (e.g. Dermol® range) to reduce bacterial colonisation.

Eczema herpeticum

Suspect if

• areas of rapidly worsening, painful eczema
• possible fever, lethargy or distress
• clustered blisters (often in one area) consistent with early-stage cold sores
• punched-out erosions (usually 1–3 mm) uniform in appearance which may coalesce.

Management

• Take viral swabs
• Treat with aciclovir tablets
• If you suspect secondary bacterial infection, start treatment with appropriate systemic antibiotics as well.
• Refer immediately (same day) for specialist dermatological advice

Patients with an orbital infection, a high temperature or those who are systemically unwell should be considered for admission into secondary care.

River or seawater exposure: consult microbiologist for advice (possible Vibrio infection).

Check MRSA status and send swabs if:

• Previously known MRSA positive
• Current inpatient of 5 days duration or longer
• Inpatient within the last 3 months
• Transferred from another hospital
• Chronic medical conditions, e.g. haemodialysis or wound care
• Resident of a nursing or residential home

The formulary gives dose and duration of treatment for adults unless stated otherwise.

Flucloxacillin

• 500mg - 1g every 6 hours for 7 days, if slow response continue for a further 7 days

Penicillin allergy

Clarithromycin

• 500mg every 12 hours for 7 days, if slow response continue for a further 7 days

If facial cellulitis

If the cellulitis is clearly not associated with mucosal structures such as the facial sinuses or teeth then treat as standard cellulitis, see above. If mucosal facial structures are involved use co-amoxiclav:

Co-amoxiclav

• 625mg every 8 hours for 7 days, if slow response continue for a further 7 days

Ulcers are always colonised.

Check MRSA status and send swabs if:

• Previously known MRSA positive
• Current inpatient of 5 days duration or longer
• Inpatient within the last 3 months
• Transferred from another hospital
• Chronic medical conditions, e.g. haemodialysis or wound care
• Resident of a nursing or residential home

Antibiotics should only be used in active infection (increased pain, pyrexia, erythema beyond 2cm, localised heat). If antibiotics given, review with culture results.

If antibiotics are required treat with cellulitis regimen (see above)

The 5-day decolonisation protocol consists of all or some of the following products, depending on colonised sites. Obtain further advice from Infection Control if necessary.

• Chlorhexidine 4% Skin Cleanser for bathing/ showering/ washing for five days (for patients with nasal and/or skin carriage). Use as liquid soap with a disposable wipe. Do not use patient's flannel. If the patient's condition allows, also use to wash hair. Specialist dermatology advice should be sought prior to decolonising patients with skin disorders, e.g. eczema, psoriasis. Octenisan may be useful for babies and sensitive skin
• Mupirocin 2% nasal ointment applied to each nostril three times daily (for patients with nasal carriage and /or skin carriage). Apply using a cotton bud or gloved fingertip
• Mupirocin 2% cream applied to small superficial wounds three times a day. If wounds are healing despite the presence of MRSA, it will probably be more harmful to disturb the wound three times a day to apply mupirocin – in which case normal wound care should continue. Mupirocin is not appropriate for large or complex wounds

An MHRA patient information leaflet is available on the Public Health England (HPA) website.

Human bites: Thorough irrigation is important. Assess risk of tetanus, HIV, hepatitis B&C- follow inoculation policy. Antibiotic prophylaxis is advised.

Cat / dog / bat bites: Assess risk of tetanus and rabies- follow inoculation policy.

Give prophylaxis if:

• All cat bites
• Puncture wound from any animal
• Bite to hand, foot, face, joint, tendon, ligament. If the bite is near a joint or tendon, refer to plastics.
• Immunocompromised / diabetic / asplenic / cirrhotic
• Contact Microbiology if the bite is from an unusual animal, or presents more than 24 hours after the bite.

Prophylaxis and treatment

Co-amoxiclav

• 625mg every 8 hours for 7 days

Penicillin allergy

Metronidazole

• 400mg every 8 hours for 7 days, plus

Doxycycline

• 100mg every 12 hours for 7 days

Treat all home and sexual contacts within 24 hours

Application notes

1. Take an ordinary tepid bath
2. After drying the skin apply to the whole body including face, neck, scalp & ears
3. Reapply if hands are washed in this 48 hour period
4. 24 hours later take another bath and change underclothes, nightclothes, sheets and pillow cases

Permethrin 5% cream

• Two applications one week apart

If allergy

Malathion liquid 0.5% aqueous liquid

• Two applications one week apart

Skin: localised infection

The use of OTC dusting powders and creams can be recommended to help prevent re-infection of athlete's foot.

Oral therapy is indicated in scalp infections; discuss with specialist.

Terbinafine is fungicidal and the treatment time is shorter than with fungistatic imidazoles.

Terbinafine 1%

• Topical: apply every 12 hours for 1-2 weeks after visible clearance (i.e. 4-6 weeks) to reduce relapse

Miconazole 2%

• Topical: apply every 12 hours for 1-2 weeks after visible clearance (i.e. 4-6 weeks) to reduce relapse

Clotrimazole 1%

• Topical: apply 2-3 times daily for 1-2 weeks after visible clearance (i.e. 4-6 weeks) to reduce relapse

Skin: extensive infection or failure to respond to topical anti-fungal

Take skin scrapings for culture for intractable infections, and if infection confirmed consider oral terbinafine/ itraconazole.

Terbinafine

• Oral: 250mg daily for 4 weeks

Itraconazole

• Oral: 200mg daily for 7 days
• Use twice daily for palm or sole infections
• See warnings below

Proximal fingernail or toenail (adults)

Take nail clippings and only start therapy if infection is confirmed by laboratory.

Oral terbinafine is more effective than oral azoles (fungicidal agent). Idiosyncratic liver reactions occur rarely with terbinafine.

Terbinafine

• Oral: 250mg daily
• Treat fingernails for 6 to 12 weeks
• Treat toenails for 12 weeks

Pulsed itraconazole monthly is recommended for infections with candida and non-dermatophyte moulds.

Itraconazole

• Oral: 200mg twice daily for 7 days of each month
• Treat fingernails with 2 courses
• Treat toenails for 3 courses
• See warnings below

Warnings on itraconazole use

1. Itraconazole has a negative inotropic effect.
   1. It should not be used in patients with heart failure or at risk of it.
   2. It should not be used with other negatively inotropic drugs such as calcium channel blockers.
2. Itraconazole has a range of clinically important drug interactions such as statins, anti-epileptics, anti-arrhythmics, antihistamines, calcium channel blockers, HIV drugs. This list is not exhaustive and the BNF or other texts should be consulted.
3. Absorption of itraconazole is pH dependent. It is reduced by antacids and PPIs. Avoid antacids for 2 hours. If on a PPI, take itraconazole with an acidic drink.
4. Do not use itraconazole if there is a past history of hepatic disease.

Varicella zoster/chicken pox and herpes zoster/shingles

Pregnant / immunocompromised / neonate: exposed to chicken pox or shingles: seek urgent specialist advice

Chicken pox, consider aciclovir:

• If onset of rash less than 24 hours & over 14 years of age or
• Severe pain or
• Dense/oral rash or
• Secondary household case or
• Taking steroids or
• A smoker

Shingles, treat if over 50 years of age and:

• Within 72 hours of rash (post herpatic neuralgia is rare if under 50 years of age) or
• Active ophthalmic or
• Ramsey Hunt syndrome or
• Eczema

If indicated

Aciclovir tablets

• 800mg five times daily for 7 days
• Child doses see BNFC

Cold sores resolve after 7–10 days without treatment.

Topical antivirals applied prodromally reduce duration by 12-24 hours