Cellulitis: bacteriology was not very good as detecting infecting pathogens.

Clinical bottom line (level 4)

Three-quarters of patients with cellulitis or erysipelas had positive serology for streptococcal or staphylococcal infection.
Around 40% had a culture positive for a known pathogen.

Leppard et al: British Journal of Dermatology 1985; 112: 559-567

Expires November 2004

The study

Case series with ?objective ?blinded outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: university hospital, UK, 1980-2

35 patients (aged range 38 to 84 years, 57% female) cellulitis or erysipelas referred for further assessment during an epidemic of necrotising fasciitis.

Outcomes studied:

positive bacterial culture from draining fluid, ulcers or fissures, or blisters
serology positive for Staphylococcus and Streptococcus

The evidence

outcome	time to outcome	number of patients/total number	% (95% CI)
positive bacterial culture	?	15/35	43% (26% to 59%)
serology positive	?	26/35	74% (60% to 89%)

All patients with erysipelas were systemically unwell - only one was taking any immunosuppressive drugs; none had diabetes. Patients with cellulitis were less ill; one was receiving steroids.
Needle aspiration was attempted in first 12 patients with erysipelas, but failed in each so was abandoned.

Comments

Extremely low rate of cellulitis and erysipelas - unlikely that all patients in the area were actually referred.
Unclear how many patients had their management changed on the basis of these investigations.

Citation

Leppard BJ, Seal DV, Colman G, et al: The value of bacteriology and serology in the diagnosis of cellulitis and erysipelas. British Journal of Dermatology 1985; 112: 559-567

_{Clinical Question.}

_Patient	_{cellulitis or erysipelas}
_{Intervention or Exposure}	_prevalence
_Outcome	_{positive serology}