PARIS — Patients colonized with certain enterotoxic strains of Staphylococcus aureus had significantly worse Psoriasis Area and Severity Index scores than did patients not colonized with these bacterial strains, raising the possibility that antibiotics might have an adjunctive role in treatment, Austrian dermatologists reported at the European Congress on Psoriasis 2004.
Nordwig S. Tomi, M.D., and Elisabeth Aberer, M.D., of Karl Franzens University in Graz, Austria, theorized that enterotoxins might act as superantigens in stimulating dysfunction within T-cells and keratinocytes, triggering psoriasis.
To test the hypothesis, they took sample swabs from the lesional skin and nares of 25 patients with psoriasis for evidence of S. aureus colonization and identification of enterotoxins A, B, C, or D.
Samples from 15 of 25 patients grew positive cultures; these samples were from the nares alone in 1 patient, skin only in 4 patients, and skin and nares in 10. Sixty percent of the strains produced S. aureus enterotoxins.
Enterotoxin A was not detected in any patient, but four patients had enterotoxin B, two had enterotoxin C, one had D, and combinations of A plus D and B plus C were found in one patient each.
“The Psoriasis Area and Severity Index score was significantly higher (P = .001) in patients with enterotoxin-producing staphylococcal strains,” the investigators reported in a poster presentation at the meeting.
“Our results support the hypothesis that S. aureus enterotoxins can trigger psoriasis,” they concluded, noting that in patients with exacerbated psoriasis and a positive S. aureus enterotoxin profile, “antibiotics could be a supporting treatment tool.”
The dermatologists called for more research into the mechanisms by which superantigens may trigger psoriasis.