Candida and psoriasis.

Sir, I was not surprised that Dr Flytström and co-workers failed to cultivate Candida in the intertriginous areas of psoriatics (1). As I showed, over 30 years ago, Candida acts as a primer and disappears when Gram-negative bacteria come along to replace it (2). This does not mean that the yeast is unable to do harm to the skin. Once applied on the folding skin where occlusion is provided, it produces a pustular dermatitis that heals spontaneously when left to dry, but, when humidity is high enough, it is replaced by Gram-negatives that work as perpetuators of the dermatitis. This has been shown in the interdigital spaces, but it is likely to occur in all intertriginous folds. Nowonder therefore that cultures do not yieldCandida in the intertriginous areas of psoriatics. The yeast is no longer there, but its köbnerizing effect has already taken place.