Demodicosis (mange) is fairly common in the hamster and can be caused by two species of mites, Demodex criceti and Demodex aurati. Both of these mites are normally resident on the skin of hamsters and a clinical disease is usually only seen in malnourished, elderly and/or immunodepressed animals. The clinical manifestations are alopecia, erythema, scales and crusts; pruritus is not usually present (Fig. 1). The diagnosis is made from skin scrapes and microscopic observation of the parasites. D. criceti is shorter and stubbier (Fig. 2) while D. aurati has a longer and thinner shape (Fig. 3). The treatment consists of baths with amitraz (250 ppm) once a week, until a month after the skin scrapes have become negative. The owner should, however, be warned that the affected animal probably has another disease, for example a tumour, which may well become evident later; for this reason treatment of demodicosis rarely resolves the problem completely.
Infestations by Notoedres may be found rarely: these infestations cause otitis with the development of yellowish crusts, but may also give rise to alopecia and erythema of the ears, muzzle, paws, tail and genital area. In these cases there is severe pruritus. The diagnosis is confirmed from examination of the material in the ear and of skin scrapes. The treatment is administration of ivermectin.