dermatologic disorders
Hand and Foot Dermatitis
Pathophysiology of Hand and Foot Dermatitis
A hallmark histologic feature of dermatitis is edema between epidermal keratinocytes (spongiosis). When enough edema accumulates, cell-cell adhesions (desmosomes) rupture, forming microvesicles. The microvesicles become visible macroscopically only after they enlarge. In areas other than the hands and feet, these vesicles typically rupture quickly and are not noticed. However, on the hands and feet, because of their thicker stratum corneum, vesicles tend to persist longer and become visible. Visibility of these vesicles indicates dyshidrotic dermatitis (a misnomer because it has nothing to do with sweating or abnormal sweat glands). The most severe form of dyshidrotic dermatitis, pompholyx, is characterized by coalescence of vesicles, forming larger bullae. Pompholyx is called cheiropompholyx when on the hands, podopompholyx when on the feet, and cheiropodopompholyx when on both hands and feet. 