Korean J Dermatol.
1976 Mar;14(1):5-16.
The Studies of the Pathogenicity of Demodex Folliculorum and the Treatment of Demodididosis
Abstract
- The pathogenicity of Demodex folliculorum (DF) is not well established, becausc this cutaneous parasite can be found very often not only from acneic skin lesions but also on healthy human skin, surface, particularly on sebaceous gland-rich and functionaIly active areas of the skin, i.e. on face, and therefore, the mite has been generally considered as normal inhabitant of human skin. However, as is the case with candidiasis, the parasite could also be pathogenic in the state of disturbed host-para-site relationship. To find out the pathogenicity of the mite, the authors studied the incidence of finding DF from different sites of face in several groups of 60 acneic patients (various types of acne vulgaris and rosacea) and 30 normal subjects as control. And the results obtained were as follows: the mite was found in 33 cases out of the acnei patients (55%), in male patients 67% (12 out of l8) were positive and in fernales 50% (21 out of 42). In the control group of 3O (15 each sex), 17 cases (9 males and 8 females) had thc mite, the incidence rate being 57%, The incidence rate of DF in various types of acneic skin lesions were: 85% in rosacea. 80% in pustular acne 71% in cvstic acne and 32% in papular acne. The distribution of the mite in various sites of the face differed markedly in the acneic and normal groups. In the control group 17 (57 %) were positive on nose, 3 (10%) on cheek, 2 (7%) on chin, and none on the forehead. Among 60 acneic patients, however, 18 (30%) were positive on cheek, 17 (28%) on nose, 15 (25%) on chin 12 (20 %) on forehead. In addition, the acuthors observed two cases of demodicidosis in the dogs. These two dogs were siblings and lived together with other dogs of the same lineage, but the other dogs were not affected. In spite of vigorous treatment with 15 % benzyl benzoate aqueous emulsion and 10 % crotamiton ointment applied topically for two to three weeks, the dogs died within one to two months. Slight improvement only was noted in the first week of the treatment, but the dogs were gradually emaciated, leading to death. At the onset of the disease, both dogs were two to three months old. Histopathological studies of the affected skin revealed dense patchy lymphocytic infiltration predominantly in perifollicular area, follicular keratotic plugging and egg-like materials in the Iumen of hair follicle. Histopathology of the affected canine skin appeared similar to that of human demodicidosis except that the mitelike material was observed lodged in the lumen of hair follicle. The morphology of demodex folliculorum canis seemed slightly different from that of the human strain (DF hominis). It is generally smaller in size and has narrower and shorter stunted abdomen than human strain, otherwise it is almost alike. The human demo3icrdosis can be effectively treated with 15% benzyl benzoate aqueous emulsion, 1% gamma benzene hexachlrode cream and 10 % crotamiton ointment, and it seems to be most effective agent being crotamiton ointment among them. It is suggested that demodex folliculorum, which has been hitherto thought to be harmless, can be pathogenic in certain individuals and that some immunologic factors might be implicated in the process of the demodicidosis.
