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Three Part Question

IN [children with infected atopic dermatitis] WILL [a swab] INFLUENCE [the choice of antibiotic treatment]?

Clinical Scenario

A six year old boy attends the Paediatric Emergency Department. He has area of broken eczematous skin that appears to be infected. He has been treated with Flucloxacillin but it appears to have made no difference.

You wonder if other bacteria may be present or if there is antibiotic resistance and what antibiotic to use.

Search Strategy

Cochrane database, OVID medline< 1950 to June Week 3 2010, EMBASE < 1980 to Week 25 2010. CINAHL.
Cochrane database: 'atopic dermatitis' OR 'eczema'.
OVID Medline/EMBASE/CINAHL: (exp dermatitis,atopic OR exp eczema) AND (exp infection OR exp bacteria) LIMIT to child < 18 years AND human AND english language.

Search Outcome

Cochrane database: 37 found. 0 relevant.
OVID Medline: 408 found. 3 relevant.
EMBASE: 619 found. 2 relevant.
CINAHL: 205 found. 0 relevant.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Ortega-Loayza et al May 2010 United States	93 children aged 0 to 18 years with infected skin conditions recruited from a dermatology clinic. 61 (66%) children had atopic dermatitis.	Prospective observational study. Swabs were taken from children presenting with signs of skin and soft tissue infection.	141 cultures were analysed	97 cultures were Staphylococcus aureus, 32% were methicillin-resistant. 31 patients had multiple cultures. 3.5% had streptococcus infections. Also found were enterococcus and diphtheroids.	Sample size not discussed. Person(s) performing skin swabs are not mentioned, results may have differed depending on the way sample was taken.
			97 cultures were tested for antibiotic susceptibility	Penicillin resistance 86%, erythromycin resistance 46%, methicillin 32%, clindamycin 22%, gentamicin 3%
			Methicillin-resistant Staphylococcus aureus had multiple resistance	Erythromycin resistance 71%, clindamycin 16%, gentamicin 2%
Ricci at el September-October 2003 Italy	81 children aged 2 months to 9 years with exudative moderate to severe atopic dermatitis recruited from a dermatology clinic.	Prospective observational cohort study. Swabs were taken from all children with exudative eczematous lesions.	308 samples were taken	52 (64.2%) children were colonised with Staphylococcus aureus. 5 with Streptococcus pyogenes. 1 with Candida albicans.	Sample size not mentioned. No standardisation of sample taking. No basic epidemiological data about the patients.
Arkwright et al July 2002 United Kingdom	150 records of children aged 0 to 16 years with atopic dermatitis who had skin swabs taken for suspected infection.	Retrospective cohort study.	Staphylococcus aureus identified	All samples (100%): all were resistant to at least one antibiotic	No attempt to standardise swab technique. No mention of inclusion criteria. No basic epidemiological data about the patient group.
			Pyogenes streptococci identified	80 samples (53%)
			Methicillin-resistant staphylococcus aureus (MRSA) identified	15 samples (19%)

Comment(s)

The papers show that a range of bacteria can infect atopic dermatitis. The most common bacterium found was Staphylococcus aureus. Treatment should therefore be initiated to treat this organism. Staphylococcus aureus was found to vary in resistance including resistance to methicillin (MRSA). A skin swab should be taken to allow the identification of another organism or resistance and the most effective antibiotic treatment to be given.

Clinical Bottom Line

A skin swab should be taken when infection of atopic dermatitis is suspected in order to provide effective antibiotic treatment.

References

1. Ortega-Loayza AG, Diamantis SA, Gilligan P and Morrell DS. Characterization of Staphylococcus aureus cutaneous infections in a paediatric dermatology tertiary health care outpatient facility Journal of the American Academy of Dermatology May 2010;62(5):804-11
2. Ricci G, Patrizi A, Neri I, Bendandi B and Masi M. Frequency and clinical role of Staphylococcus aureus overinfection in atopic dermatitis in children. Pediatric Dermatology September-October 2003;20(5):389-92.
3. Arkwright PD, Daniel TO, Sanyal D, David TJ, Patel L. Age-related prevalence and antibiotic resistance of pathogenic staphylococci and streptococci in children with infected atopic dermatitis at a single-specialty center. Archives of Dermatology July 2002;138(7):939-41.