ABSTRACT
Itch is a subjective phenomenon, and itch models in animals are restricted by the fact that animals cannot express whether they scratch themselves due to itch or due to other sensations, such as pain or discomfort, or for no special reason at all (l,2). Therefore, scratching in animals has been regarded as an indirect correlate to itch. So far, only a few valid animal models for pruritus have been established. Spontaneous scratching in rats is probably a cerebral phenomenon or otherwise explained as a general behavior, rather than as a reaction to skin stimuli (3). Feeding rats a diet low in magnesium induces a skin rash, which may share features with atopic dermatitis (4,5). The rash is attributed to lowered serum Mg2 + and described in the literature as extremely pruritic (6). Sometimes, the diet is also low in fat (7), but dietary lipid depletion probably does not play any significant role in the pathogenesis of the hypomagnesic dermatitis rat model (8).
