EXFOLIATIVE dermatitis is not a common disorder. Crocker (1903) estimated its incidence at 3 per 2,000 and Lancashire (1927) at 1 per 2,250 cases of skin disease. In the latter half of the last century several types of this condition were recognized in adults. The more important of these were erythema scarlatiniforme (Féréol, 1876), epidemic exfoliative dermatitis (Savill, 1891), pityriasis rubra (Hebra, 1868), and the Wilson-Brocq type of exfoliative dermatitis (Wilson, 1867). Each of these had certain characteristic features, but there is no evidence that any of them was a distinct clinical entity.
A fresh approach to the subject was made by Baxter (1879), who divided all cases into the so-called "primary" and "secondary" types and recognized that it was often impossible to distinguish between the two by clinical observation alone.
The primary cases developed in an apparently healthy person; the secondary ones supervened upon a previous skin disease, such