Data in the literature regarding the prevalence of Candida in psoriatic and atopic dermatitis patients are controversial. We conducted a prospective study to determine the prevalence of Candida on the tongue, axillae and groin of psoriatic patients when compared with atopic dermatitis patients and normal controls. During the period 2003-2005, data were collected from 100 psoriatic patients, 100 patients with atopic dermatitis and 100 normal controls. Fungal test specimens for Candida were collected from the axillae, groin and tongue of each patient. There was no increase in the prevalence of Candida in intertriginous area of either psoriatic or atopic dermatitis patients. However, the prevalence of Candida on the tongue was significantly higher in psoriatic patients (32%) compared with atopic dermatitis (18%) (P = 0.024) and higher, although not significantly, than in normal controls (21%) (P = 0.08). Our study did not reveal higher prevalence of Candida in the axillae and groin of either psoriatic or atopic dermatitis patients. There was a higher prevalence of Candida on the tongue of psoriatic patients. The Candida of the tongue was asymptomatic and did not correlate with age, gender, type of psoriasis or severity of the disease, therefore we conclude that this is clinically irrelevant.

Comparison of three test methods used for the diagnosis of candidiasis.Scand J Dent Res. 1994 Oct;102(5):295-8.

A total of 266 specimens was taken from oral mucosa or dentures of 88 patients with suspected Candida-infected oral mucosa. One-third of the debris from each sample was cultured on Microstix-Candida (C), strips, one-third was cultured on Oricult-N-plates, and the rest was collected on glass plates and stained by the periodic acid-Schiff (PAS) method. The PAS-stained samples were analyzed under the light microscope for the presence of Candida hyphae. The other samples (Oricult-N or Microstix-C) were studied visually, according to the manufacturer's recommendation. PAS-stained specimens showed significantly less often positive results than those of the two culture methods. These data suggest that oral candidiasis may be incorrectly diagnosed if based upon results obtained with the culture methods. It is also possible that the PAS-staining method yielded false negative findings. This possibility should always be considered, especially if other findings and symptoms disagree with the test results obtained.