Comparison of Demodex folliculorum density in haemodialysis patients with a control group

Demodex folliculorum (DF) is resident in human pilosebaceous follicles. Mite density is low in healthy skin. Many cases of demodicosis in association with immunosuppression have been reported. Patients undergoing haemodialysis are also immunosuppressed.

We aimed to compare the Demodex folliculorum density in haemodialysis patients and healthy subjects.

Mite density of 87 patients undergoing haemodialysis was compared with that of age- and sex-matched controls. Two samples of standardized skin surface biopsies were taken from each subject from the forehead, cheek and nose. The number of mites counted on the surface area of 1 cm2 was accepted as the density of DF. The length and width of mites were measured by oculometer.

DF density was found in 17 (19.54%) of the 87 dialysis patients and in 9 (10.34%) of 87 controls. A mean mite density of 5.11+/-5.65 was found in dialysis patients and of 2.55+/-1.6 in controls. Differences between the two groups in mite density were not statistically significant (P=0.13). There was also no significant difference in mite length between the two groups (P=0.06). There was, however, a significant difference in mite width (P=0.018).

Despite the presence of sebaceous gland atrophy in haemodialysis patients, the higher density of DF in these patients than controls supports the supposition that this mite can increase immunosuppression.