Phòng khám chuyên khoa da li�u - Thạc s� bác s� Hu�nh Văn Quang

Skin and soft tissue infectionsBacterial infections

Skin and soft tissue infectionsBacterial infections

 

Bites and clenched fist injuries

 

Bites and clenched fist injuries often become infected. The organisms involved in human bites and clenched fist injuries are Staphylococcus aureus, Eikenella corrodens, Streptococcus species and beta-lactamase-producing anaerobic bacteria. The organisms involved in animal bites are Pasteurella species, Staphylococcus aureus, Capnocytophaga canimorsus, Streptococcus species and anaerobes. Cat bites have a higher incidence of infection than dog bites. In all cases a patient's tetanus immunisation status must be assessed. Postexposure rabies or Lyssavirus prophylaxis may need to be considered, eg bat bite.

 

The recommended management for human and animal bites and clenched fist injuries is thorough cleaning, debridement, irrigation, elevation and immobilisation.

 

Low risk

Antibiotics may not be necessary for mild wounds not involving tendons or joints that can be adequately debrided and irrigated and that are seen within 8 hours.

 

High risk

Wounds having a high risk of infection include:

·            wounds with delayed presentation (>=8 hours)

·            puncture wounds unable to be debrided adequately

·            wounds on hands, feet or face

·            wounds with underlying structures involved, eg bones, joints, tendons

·            wounds in the immunocompromised patient.

Presumptive therapy is necessary, use

amoxycillin+clavulanate (child: 22.5+3.2 mg/kg up to) 875+125 mg orally, 12-hourly for 5 days.

 

If the commencement of the above is likely to be delayed, give

procaine penicillin (child: 50 mg/kg up to) 1.5 g IM, as 1 dose, followed by amoxycillin+clavulanate as above.

 

For patients hypersensitive to penicillin, see Established infection below.

 

If obviously infected, a wound swab should be taken. Delaying primary wound closure should also be considered.

For severe and penetrating injuries, especially those involving joints and/or tendons, use initially

	metronidazole (child: 10 mg/kg up to) 400 mg orally, 12-hourly for 5 to 10 days
	PLUS EITHER
1	cefotaxime (child: 50 mg/kg up to) 1 g IV, 8-hourly for 5 to 10 days
	OR
1	ceftriaxone (child: 50 mg/kg up to) 1 g IV, daily for 5 to 10 days.

 

Alternatively, use

1	piperacillin+tazobactam (child: 100+12.5 mg/kg up to) 4+0.5 g IV, 8-hourly for 5 to 10 days
	OR
1	ticarcillin+clavulanate (child: 50+1.7 mg/kg up to) 3+0.1 g IV, 6-hourly for 5 to 10 days.

 

For patients with immediate penicillin hypersensitivity, use

	metronidazole (child: 10 mg/kg up to) 400 mg orally, 12-hourly for 5 to 10 days
	PLUS EITHER
1	doxycycline (child >8 years: 2 mg/kg up to) 100 mg orally, daily for 5 to 10 days
	OR
2	trimethoprim+sulfamethoxazole (child: 4+20 mg/kg up to) 160+800 mg orally, 12-hourly for 5 to 10 days
	OR
3	ciprofloxacin (child: 10 mg/kg up to) 500 mg orally, 12-hourly for 5 to 10 days.

 

Treatment should be modified according to Gram stain and culture.

If osteomyelitis is suspected, treatment duration should be extended.

Boils, carbuncles and folliculitis

 

 

Boils and carbuncles

 

The causative organism is generally Staphylococcus aureus, occasionally in association with Streptococcus pyogenes. If the lesions are small or few in number they may be managed by hot compresses with drainage if appropriate. If lesions are extensive or cause systemic symptoms, use

di/flucloxacillin (child: 25 mg/kg up to) 500 mg orally, 6-hourly for 5 to 7 days.

 

For patients hypersensitive to penicillin (excluding immediate hypersensitivity), use

cephalexin (child: 25 mg/kg up to) 500 mg orally, 6-hourly for 5 to 7 days.

 

For patients with immediate penicillin hypersensitivity, use

clindamycin (child: 10 mg/kg up to) 450 mg orally, 8-hourly for 5 to 7 days.

 

In areas where non–multiresistant MRSA strains are prevalent, a swab should be taken before initiating therapy. If this organism is isolated or strongly suspected, treatment should be guided by susceptibility testing. These strains are generally susceptible to clindamycin or trimethoprim+sulfamethoxazole as well as the drugs normally chosen for the multiresistant strains (vancomycin, rifampicin, sodium fusidate, quinupristin/dalfopristin and linezolid).

 

Recurrent staphylococcal skin infection including boils

 

Treat the acute lesions as described in boils and carbuncles. Once all lesions are healed, chronic carriage of pathogenic Staphylococcus aureus may be documented with nasal and or perineal swabs. Use

	mupirocin 2% nasal ointment intranasally, twice daily for 7 days
	PLUS
	wash daily with an antiseptic wash containing triclosan 1%, paying particular attention to hair-bearing areas, and wash clothes, towels and sheets in hot water. These measures should be continued for 4 weeks.

 

The whole family and close contacts may need similar treatment if these measures fail.

If lesions continue to recur despite good compliance, repeat the above regimen together with

	rifampicin (child: 7.5 mg/kg up to) 300 mg orally, 12-hourly for 7 days
	PLUS
	di/flucloxacillin (child: 12.5 mg/kg up to) 250 mg orally, 6-hourly for 7 days.

 

For MRSA use

fusidate sodium (child: 12 mg/kg up to) 500 mg orally, 12-hourly instead of di/flucloxacillin.

 

Successful eradication is unlikely if the strains are resistant to mupirocin or any of the antibiotics prescribed. Seek expert advice.

 Folliculitis

 

This common condition presents with mildly itchy pustules on an erythematous base. It may affect any part of the hair-bearing skin in adults and children. It is often a problem in hot weather, and often occurs in macerated areas, including under wet dressings. The patient is often a chronic carrier of Staphylococcus aureus. Folliculitis is most often due to Staphylococcus aureus infection, but this should be confirmed by culture as Pseudomonas aeruginosa, Pityrosporum species, dermatophytes and herpes simplex virus may also cause folliculitis. Folliculitis may also be ‘sterile’, although in this situation Staphylococcus epidermidis is usually cultured. A variant known as eosinophilic folliculitis occurs in human immunodeficiency virus (HIV) disease but is not infective.

Determine the causative organism, if any, by culture of a swab. Viral cultures may be indicated if the lesions suggest herpes simplex infection.

For staphylococcal infection, treat as for impetigo with a staphylococcal carrier state, since this is usually the case. For pseudomonal folliculitis, which is due to contact with contaminated water, identify the source (eg hot water tank, spa) and cease contact with it until the water supply has been treated. Sterile folliculitis is usually due to maceration, particularly in obesity, heavy sweating, contact with occlusive substances such as oils, shaving and waxing. Attention to underlying problems is appropriate in these cases, but antiseptic washes, eg triclosan 1%, chlorhexidine 2%, are also required to diminish the overgrowth of skin flora in these cases.

 

Cellulitis and erysipelas

 

 

Cellulitis presents with spreading, tender erythema, associated with fever and systemic toxicity. It may be associated with lymphangitis and lymphadenopathy. As the rash progresses, blistering may occur. The causative organism is almost always Streptococcus pyogenes, but Staphylococcus aureus is important with wound-associated cellulitis. Now that Hib vaccination is widespread, Haemophilus influenzae is a rare cause of cellulitis. In immunosuppressed patients, a wide variety of organisms including Gram-negative bacteria, fungi and mycobacteria may also be responsible.

Cellulitis in children is often periorbital. Cellulitis in adults most often affects the lower legs. It is often unilateral, at least initially and there is usually an underlying abnormality, such as tinea pedis, fissured dermatitis, lymphoedema, lymphatic malformation, previous deep vein thrombosis, vascular surgery or radiotherapy. A search for a portal of entry should be made to prevent possible recurrences. Recurrent cellulitis may result in lymphoedema, which in itself worsens the situation. Cellulitis may also complicate wounds, eg cuts, abrasions, insect bites or scabies.

Erysipelas is a localised form of cellulitis involving the face, presenting with sudden onset of butterfly erythema associated with fever, and constitutional upset. There may be an underlying facial sinus or dental infection. It is almost always caused by Streptococcus pyogenes. Dental examination and imaging of sinuses is recommended.

 

If Streptococcus pyogenes is suspected, use

1	procaine penicillin (child: 50 mg/kg up to) 1.5 g IM, daily
	OR
2	phenoxymethylpenicillin (child: 10 mg/kg up to) 500 mg orally, 6-hourly.

 

If Staphylococcus aureus is suspected, (and also covering Streptococcus pyogenes) use

di/flucloxacillin (child: 25 mg/kg up to) 500 mg orally, 6-hourly.

 

For patients hypersensitive to penicillin, use

clindamycin (child: 10 mg/kg up to) 450 mg orally, 8-hourly.

 

To treat infection with either streptococci or staphylococci, use

di/flucloxacillin (child: 50 mg/kg up to) 2 g IV, 6-hourly.

 

For patients hypersensitive to penicillin (excluding immediate hypersensitivity), use

1	cephalothin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	OR
1	cephazolin (child: 25 mg/kg up to) 1 g IV, 8-hourly.

 

For patients with immediate penicillin hypersensitivity, use

1	clindamycin (child: 10 mg/kg up to) 450 mg IV, 8-hourly THEN clindamycin (child: 10 mg/kg up to) 450 mg orally, 8-hourly
	OR
1	lincomycin (child: 15 mg/kg up to) 600 mg IV, 8-hourly THEN clindamycin (child: 10 mg/kg up to) 450 mg orally, 8-hourly
	OR
2	vancomycin (child: 20 mg/kg up to) 1 g IV, 12-hourly.

 

Intravenous home-based therapy may be used in suitable patients.

	cephazolin 2 g IV, 12-hourly for 4 to 7 days
	OR THE COMBINATION OF
	cephazolin 2 g IV, daily for 4 to 7 days
	PLUS
	probenecid 1 g orally, daily for 4 to 7 days.

 

For paediatric doses, consult an outpatient IV therapy service experienced with children.

Ceftriaxone has a broad spectrum of activity which is not required for routine cellulitis where streptococci and staphylococci are the likely pathogens.

 

Clostridial infection

This varies from mild cellulitis to overwhelming myonecrosis (gas gangrene). The basis of treatment is surgical debridement of necrotic tissue and antibiotic therapy. In severe infections, hyperbaric oxygen is an important adjunct if available. The diagnosis of gas gangrene is a clinical one. Neither the isolation of clostridia nor the presence of gas in tissue is diagnostic of the condition.

For cellulitis without myonecrosis, use

benzylpenicillin (child: 30 mg/kg up to) 1.2 g IV, 4-hourly.

 

For myositis/myonecrosis (gas gangrene), use

benzylpenicillin (child: 60 mg/kg up to) 2.4 g IV, 4-hourly.

 

For patients with immediate penicillin hypersensitivity, use

metronidazole (child: 12.5 mg/kg up to) 500 mg IV, 8-hourly.

 

Other measures, for example resuscitation, surgery and hyperbaric oxygen, are vitally important and require expert advice.

 

Compound fractures

Prophylaxis or early treatment directed particularly against Staphylococcus aureus should be given. The patient's immune status to tetanus should be assessed.

1	di/flucloxacillin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	OR
2	cephalothin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	OR
2	cephazolin (child: 25 mg/kg up to) 1 g IV, 8-hourly
	OR
3	clindamycin (child: 10 mg/kg up to) 450 mg IV, 8-hourly
	OR
3	lincomycin (child: 15 mg/kg up to) 600 mg IV, 8-hourly.

 

Duration of prophylaxis should be for 1 to 3 days.

If wound soiling or tissue damage is severe and/or devitalised tissue is present, add

1	gentamicin (child <10 years: 7.5 mg/kg; >=10 years: 6 mg/kg) 4 to 6 mg/kg IV, daily (adjust dose for renal function, see Monitoring of aminoglycosides)
	OR
2	ciprofloxacin (child: 5 mg/kg up to) 200 mg IV, 8-hourly THEN (child: 10 mg/kg up to)500 mg orally, 12-hourly.

 

If clindamycin or lincomycin are not used as the primary choice, then for clostridial species add either

	benzylpenicillin (child: 30 mg/kg up to) 1.2 g IV, 6-hourly
	OR
	metronidazole (child: 12.5 mg/kg up to) 500 mg IV, 12-hourly.

 

Alternatively, use

1	piperacillin+tazobactam (child: 100+12.5 mg/kg up to) 4+0.5 g IV, 8-hourly
	OR
1	ticarcillin+clavulanate (child: 50+1.7 mg/kg up to) 3+0.1 g IV, 6-hourly.

 

Duration of treatment should be for 5 to 7 days, or longer if bone infection is established, see Bone and joint infections.

 

Diabetic foot infections

 

Diabetic foot infections should always be regarded as serious, and treated vigorously. Culture may be unhelpful because of polymicrobial infections and superficial colonisation but may guide therapy particularly if Staphylococcus aureus or multiresistant pathogens are found. Anaerobic organisms are almost always involved, often with mixed Gram-positive and Gram-negative aerobic organisms. Surgical debridement is often necessary and antibiotic therapy should be effective against the mixed aerobic and anaerobic organisms frequently responsible. Underlying osteomyelitis should be considered. Vascular supply should be assessed.

For mild to moderate infection with no evidence of osteomyelitis, use

	metronidazole 400 mg orally, 12-hourly
	PLUS
	cephalexin 500 mg orally, 6-hourly.

 

Alternatively, use

amoxycillin+clavulanate 875+125 mg orally, 12-hourly.

 

For patients with penicillin hypersensitivity, use

	ciprofloxacin 500 mg orally, 12-hourly
	PLUS
	clindamycin 600 mg IV, 8-hourly.

 

For severe potentially limb-threatening infection, use

1	piperacillin+tazobactam 4+0.5 g IV, 8-hourly
	OR
1	ticarcillin+clavulanate 3+0.1 g IV, 6-hourly.

 

Alternatively, and for patients with penicillin hypersensitivity, use

	ciprofloxacin 750 mg orally, 12-hourly
	PLUS EITHER
1	clindamycin 900 mg IV, 8-hourly
	OR
1	lincomycin 900 mg IV, 8-hourly.

 

For patients with evidence of osteomyelitis, see Osteomyelitis.

For severe potentially life-threatening infections, see Severe sepsis

Depending on the organisms subsequently isolated from deep tissue specimens, other antibiotic combinations may be indicated. The duration of treatment will depend upon the response.

For further information on the management of diabetes see Diabetes: diagnosis and management plan, Diabetes: specific management, Diabetes: complications, or wound care see Diabetic foot ulcers.

 

Impetigo

 

This condition is caused by Staphylococcus aureus or Streptococcus pyogenes. Both organisms may be isolated in which case Strep. pyogenes is thought to be the primary pathogen. Strep. pyogenes is usually the primary pathogen in central and northern Australia.

Impetigo presents most often in children but may be seen at any age. Clinically it may be nonbullous, presenting with yellow crusts and erosions, or bullous, presenting with mildly irritating blisters that erode rapidly leaving a brown crust. The former tends to be a less acute condition. Diagnosis is confirmed by skin swab to define the infective organism and confirm antibiotic susceptibility. The condition is contagious. If due to Strep. pyogenes, glomerulonephritis may follow within 8 weeks.

Seek and treat underlying dermatosis such as dermatitis, scabies or head lice.

In situations where Streptococcus pyogenes is suspected or confirmed as the primary pathogen, use

	saline OR soap and water OR aluminium acetate solution OR potassium permanganate solution topically, 12-hourly to remove crusts (see Pompholyx - Specific treatments for dermatitis)
	PLUS
	phenoxymethylpenicillin (child: 10 mg/kg up to) 500 mg orally, 6-hourly for 10 days
	OR
	benzathine penicillin (child: 30 to 45 mg/kg up to) 900 mg IM, as 1 dose (see also dosing table for children).

 

For patients with penicillin hypersensitivity, use

roxithromycin 300 mg orally, daily (child: 4 mg/kg up to 150 mg orally, 12-hourly) for 10 days.

 

In situations where Staphylococcus aureus is suspected or confirmed as the primary pathogen, for mild or localised infections, use

	saline OR soap and water OR aluminium acetate solution OR potassium permanganate solution topically, 12-hourly to remove crusts (see Pompholyx - Specific treatments for dermatitis)
	PLUS
	mupirocin 2% topically, 8-hourly for 7 days.

 

For severe, widespread or longstanding infections where Staphylococcus aureus is suspected or confirmed, use

1	di/flucloxacillin (child: 12.5 mg/kg up to) 250 mg orally, 6-hourly for 10 days
	OR
2	cephalexin (child: 12.5 to 25 mg/kg up to) 250 mg orally, 6-hourly for 10 days
	OR
3	roxithromycin 300 mg orally, daily (child: 4 mg/kg up to 150 mg orally, 12-hourly) for 10 days.

 

Each of these drugs is active against both Staph. aureus and Strep. pyogenes.

Mastitis

 

Acute mastitis is usually associated with lactation and is frequently due to Staphylococcus aureus. Poor infant positioning and milk stasis are contributory factors to the infection. Suckling should be continued or milk from the infected breast expressed manually or by pump. In the absence of systemic symptoms in early mastitis, increased feeding on the affected side and gentle expression may prevent progression.

If systemic symptoms develop, early treatment with antibiotics is important to try to prevent abscess formation.

1	di/flucloxacillin 500 mg orally, 6-hourly
	OR
2	cephalexin 500 mg orally, 6-hourly.

 

If severe cellulitis has developed, antibiotics should be given IV.

1	di/flucloxacillin 2 g IV, 6-hourly
	OR
2	cephalothin 2 g IV, 6-hourly
	OR
2	cephazolin 1 g IV, 8-hourly.

 

For patients with immediate penicillin hypersensitivity, use

1	clindamycin 450 mg IV, 8-hourly THEN 450 mg orally, 8-hourly
	OR
1	lincomycin 600 mg IV, 8-hourly THEN clindamycin 450 mg orally, 8-hourly.
	OR
2	vancomycin 1 g IV, 12-hourly.

 

Failure of symptoms to improve after 2 to 3 days suggests other pathogens or an abscess, requiring review, surgical drainage and bacteriological examination of the pus.

Necrotising fasciitis or synergistic gangrene

 

The basis of treatment is surgical removal of devitalised tissue, which reduces mortality and assists in diagnosis. Causative organisms are usually mixed aerobes and anaerobes, eg Escherichia coli, Bacteroides fragilis, streptococci and staphylococci. Use initially

	benzylpenicillin (child: 60 mg/kg up to) 2.4 g IV, 4-hourly
	PLUS
	gentamicin (child <10 years: 7.5 mg/kg; >=10 years: 6 mg/kg) 4 to 6 mg/kg IV, daily (adjust dose for renal function, see Monitoring of aminoglycosides)
	PLUS
	metronidazole (child: 12.5 mg/kg up to) 500 mg IV, 8-hourly.

 

Depending on the severity of the infection, and/or the organisms subsequently isolated, other antibiotics in combination may be indicated, eg the addition of di/flucloxacillin if Staphylococcus aureus is present.

For proven Streptococcus pyogenes necrotising fasciitis, use

	benzylpenicillin (child: 45 mg/kg up to) 1.8 g IV, 4-hourly
	PLUS EITHER
1	clindamycin (child: 15 mg/kg up to) 600 mg IV, 8-hourly
	OR
1	lincomycin (child: 15 mg/kg up to) 600 mg IV, 8-hourly.

 

For patients hypersensitive to penicillin (excluding immediate hypersensitivity), substitute for benzylpenicillin

1	cephalothin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	OR
1	cephazolin (child: 25 mg/kg up to) 1 g IV, 8-hourly.

 

 

Paronychia

 

Chronic paronychia is painless and is a traumatic nail dystrophy. Pushing back the cuticles, or removal of the cuticles through keratolytics (as used by manicurists) damages the waterproof seal between the proximal nail fold and the nail plate that protects the nail matrix. Once damaged, water and debris can enter the nail matrix and produce inflammation of the undersurface of the proximal nail fold.

Loss of the cuticle is an essential feature of the diagnosis; if the cuticle is intact, consider other causes of swelling of the proximal nail fold. Nail biting is commonly associated. Treatment is dependent on correct care of the cuticle.

Secondary infection with Candida is common. Although Candida may aggravate the problem, it does not cause it; paronychia is essentially a problem caused by nail manicure that damages the integrity of the cuticle. Chronic paronychia may be aggravated by episodes of acute paronychia caused by secondary infection with staphylococci (see below).

Advise patients to:

·            not push back their cuticles or manicure their nails

·            avoid playing with or picking at their cuticles

·            never insert anything beneath the cuticle to clean out debris

·            keep their hands out of water, and wear cotton-lined rubber gloves when doing the dishes or other wet work

·            wear cotton gloves in the garden and leather gloves in cold weather

·            use a mild soap and shampoo to minimise irritation in the shower

·            continue with meticulous hand care until the cuticle regenerates (approximately 6 weeks).

 

Topical corticosteroids are helpful. Use

a potent or very potent topical corticosteroid topically, once daily for 14 to 21 days.

 

If there is secondary Candida infection, add

miconazole 2% tincture topically, twice daily for 5 to 7 days.

 

When there is persistent exudate, use an antiseptic tincture to dry out the area:

thymol 4% in alcohol 70%, applied with a dropper to the base of the nail.[Note 1]

 

When the area is dry and without exudate, to waterproof and protect the area, use

white soft paraffin topically, 5 to 10 times daily.

 

Refer unresponsive cases to a dermatologist.

 

Acute paronychia is due to bacterial (usually staphylococcal) or, rarely, viral (herpes simplex virus) infection. It may aggravate chronic paronychia. The proximal nail fold becomes painful and pus should be drained.

For staphylococcal infection not responding to drainage, use

di/flucloxacillin (child: 25 mg/kg up to) 500 mg orally, 6-hourly for 7 days.

 

For patients hypersensitive to penicillin (excluding immediate hypersensitivity), use

cephalexin (child: 12.5 mg/kg up to) 500 mg orally, 6-hourly for 7 days.

 

For patients with immediate penicillin hypersensitivity, use

clindamycin (child: 10 mg/kg up to) 450 mg orally, 8-hourly for 7 days.

 

For infection caused by herpes simplex virus (herpetic whitlow), use

1	valaciclovir 500 mg orally, 12-hourly for 7 to 10 days
	OR
2	famciclovir 250 mg orally, 12-hourly for 7 to 10 days
	OR
3	aciclovir (child: 5 mg/kg up to) 200 mg orally, 5 times daily for 7 to 10 days.

 

Aciclovir is the preferred treatment in children with acute paronychia caused by herpes simplex virus.

 

Superficial thrombophlebitis

 

Superficial thrombophlebitis may occur spontaneously and antibiotics are not indicated. However, thrombophlebitis related to an IV catheter is usually due to Staphylococcus aureus infection and antibiotic therapy should be given as for suspected bacteraemia in the presence of intravascular cannulae, see Severe sepsis, intravascular device source. The infected catheter should be removed and the tip, together with blood cultures from another site, sent for culture. Surgical drainage of purulent material and/or removal of the infected clot may sometimes be required.

Varicose or decubitus ulcers

 

Local measures similar to those for postoperative wound infections are most important. If there is surrounding cellulitis, treat with systemic antibiotics as for diabetic foot infections, as the organisms involved are similar.

Water-related skin and soft tissue infections

 

In a patient presenting with a wound infection, cellulitis or sepsis which may be related to contact with water, eg in fishermen, swimmers or aquarium owners, the following organisms may be encountered: Aeromonas species (source: fresh or brackish water); Mycobacterium marinum (source: fish tanks); Shewanella putrefaciens, Vibrio vulnificus, Vibrio alginolyticus and other noncholera vibrios (source: salt or brackish water).

Treatment of most of these infections is difficult and advice should be sought from a clinical microbiologist or an infectious diseases physician. In mild infection, treatment may be given as for mild early cellulitis.

 

Infections by Aeromonas species are associated with exposure to fresh or brackish water or mud (water activities, caving) through cuts and abrasions. The resulting illness may be a superficial skin infection, myositis or sepsis with metastatic complications. In about 25% of cases the patient has an underlying systemic illness.

ciprofloxacin (child: 5 mg/kg up to) 300 mg IV or (child: 10 mg/kg up to) 500 mg orally, 12-hourly.

 

Meropenem or imipenem are possible alternatives for polymicrobial infection.

 

Coral cuts are often infected with Streptococcus pyogenes, but infection may also occur with marine pathogens. For mild infection, treat as for impetigo, and if unresponsive or severe, treat as for severe cellulitis. Treatment may need to be modified depending on response and culture results.

 

For the treatment of Mycobacterium marinum infections, see Nontuberculous mycobacteria.

 

Vibrio species should be suspected in skin infections in patients who have been exposed to salt water. Local management of skin lesions may include incision, drainage and debridement. There is considerable variability in antimicrobial susceptibility. Initial treatment should include

doxycycline (child >8 years: 2 mg/kg up to) 100 mg orally, 12-hourly.

 

Alternative antibiotics which could be considered are cefotaxime, ceftriaxone, ciprofloxacin or minocycline.

Wound infections

 

Postoperative wound infections

 

Local measures such as surgical drainage and irrigation with sodium chloride 0.9% will usually suffice. Topical antibiotics may cause skin hypersensitivity and the emergence of resistant organisms, and are not recommended. In all cases a patient's tetanus immunisation status must be assessed, see Table 2.23.

For mild to moderate infection with surrounding cellulitis, use

1	di/flucloxacillin (child: 25 mg/kg up to) 500 mg orally, 6-hourly
	OR
2	cephalexin (child: 25 mg/kg up to) 500 mg orally, 6-hourly.

 

Alternatively, if Gram-negative organisms are suspected or known to be involved, use

amoxycillin+clavulanate (child: 22.5+3.2 mg/kg up to) 875+125 mg orally, 12-hourly.

 

For more severe infections particularly where systemic symptoms are present, use

1	di/flucloxacillin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	OR
2	cephalothin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	OR
2	cephazolin (child: 25 mg/kg up to) 1 g IV, 8-hourly.

 

If Gram-negative organisms are suspected or known to be involved, add

gentamicin (child <10 years: 7.5 mg/kg; >=10 years: 6 mg/kg) 4 to 6 mg/kg IV, daily (adjust dose for renal function, see Monitoring of aminoglycosides).

 

If there is a high incidence of MRSA in the surgical unit, use

vancomycin (child: 20 mg/kg up to) 1 g IV, 12-hourly.

Post-traumatic wound infections

 

Generally, antibiotics are used in the early treatment of contaminated wounds following significant injury such as muscular, skeletal and soft tissue trauma, crush injuries and stab wounds. Antibiotics are not routinely required in all wounds. Careful cleaning and debridement of wounds is important in preventing infection, and immobilisation and elevation are also helpful. Likely pathogens include Staphylococcus aureus, Streptococcus pyogenes, Clostridium perfringens and aerobic Gram-negative bacilli. In all cases a patient's tetanus immunisation status must be assessed, see Table 2.23.

Surgical removal of devitalised tissue and other measures are vitally important and require expert advice.

 

Antibiotics are seldom necessary, however, if management is delayed or debridement difficult, use

	di/flucloxacillin (child: 25 mg/kg up to) 500 mg orally, 6-hourly for 5 to 7 days
	PLUS
	metronidazole (child: 10 mg/kg up to) 400 mg orally, 12-hourly for 5 to 7 days.

 

Alternatively, use

amoxycillin+clavulanate (child: 22.5+3.2 mg/kg up to) 875+125 mg orally, 12-hourly for 5 to 7 days.

 

 

	di/flucloxacillin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	PLUS
	gentamicin (child <10 years: 7.5 mg/kg; >=10 years: 6 mg/kg) 4 to 6 mg/kg IV, daily (adjust dose for renal function, see Monitoring of aminoglycosides)
	PLUS
	metronidazole (child: 12.5 mg/kg up to) 500 mg IV, 12-hourly.

 

Alternatively, use

	metronidazole (child: 12.5 mg/kg up to) 500 mg IV, 12-hourly
	PLUS EITHER
1	cephalothin (child: 50 mg/kg up to) 2 g IV, 6-hourly
	OR
1	cephazolin (child: 50 mg/kg up to) 2 g IV, 8-hourly.

 

Duration of treatment should be at least 5 days.

If antibiotic prophylaxis against gas gangrene is required, to the initial regimen add

benzylpenicillin (child: 60 mg/kg up to) 2.4 g IV, repeat in 4 hours if necessary.

 

Refer to perforated viscus, and compound fractures.

Tetanus prophylaxis 

 

Time since vaccination	Type of wound	Tetanus toxoid	Tetanus immunoglobulin
History of 3 or more doses of tetanus toxoid
<5 years	all wounds	no	no
5 to 10 years	clean minor wounds	no	no
	all other wounds	yes	no
>=10 years	all wounds	yes	no
Uncertain vaccination history or <3 doses of tetanus toxoid
	clean minor wounds	yes	no
	all other wounds	yes	yes

 

 

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