The group of resistant, maculopapular, scaly erythrodermias comprises erythrodermie pityriasique en plaques disseminées (Brocq), dermatitis psoriasiformis nodularis (Jadassohn), pityriasis lichenoides chronica (Juliusberg), lichenoid psoriasiform exanthem (Neisser) and parakeratosis variegata (Unna, Pollitzer and Santi).
In 1902, Brocq suggested the term parapsoriasis, to include all of these, and differentiated three distinct types: parapsoriasis en gouttes, parapsoriasis lichenoides and parapsoriasis en plaques.
While these three types are alike in histologic architecture, symptomatology and rebelliousness to treatment, they are easily and sharply differentiated on the basis of their respective eruptive elements.
All writers are in accord that the etiology is unknown and that no method of treatment has proved successful.
Having had under recent observation three cases, one of each type, it has seemed worth while to record the case histories, emphasizing what inquiries were entered into with respect to causes and what, if any, therapeutic results were attained.
Case 1.—History and Examination