The classical morphologists of the past considered Mucha-Habermann disease (pityriasis lichenoides et varoliformis acuta) as being one of the major types of parapsoriasis. This classification has recently been challenged.
Szymanski1 has advocated removing Mucha-Habermann disease from the parapsoriasis group. He concluded from his histologic studies that it is essentially a vasculitis. Kruger and Weise2 consider it an allergic vasculitis with great histologic similarities to vasculitis allergica cutis (Ruiter). Others3,4 also have been agreeable to this removal.
A feeling that this new concept may not be entirely correct was expressed by Lorincz5 who called attention to the occasional case of pityriasis lichenoides et varioliformis acuta which gradually evolves into guttate parapsoriasis.
This problem has held our interest because we have been following for the past several years a patient whose Mucha-Habermann disease changed first into guttate parapsoriasis and then evolved into parapsoriasis en plaque. The following case
COHEN HJ, FRANK SB. Mucha-Habermann DiseaseParapsoriasis or Allergic Vasculitis? Report of a Case. Arch Dermatol. 1962;86(5):671–672. doi:10.1001/archderm.1962.01590110107017