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April 1976

Pityriasis Lichenoides and Toxoplasmosis

Author Affiliations

Iowa City, Iowa

Arch Dermatol. 1976;112(4):557. doi:10.1001/archderm.1976.01630280075030

To the Editor.—  In most instances, dermatologists are able to distinguish between pityriasis lichenoides et varioliformis acuta (PLVA), or Mucha-Habermann syndrome, and chronic guttate parapsoriasis (CGP). Unfortunately, there are occasions when it is impossible to decide between these two entities. The difficulty in separating PLVA and CGP lends support to grouping them as pityriasis lichenoides (PL).1 If PL is viewed as a continuum of dermatological pathology, PLVA can be the acute end of the spectrum and CGP can be the chronic end.Vascular alterations occur in PL. In CGP, they are mild and consist simply of a perivascular lymphocytic infiltrate. In PLVA, the vascular changes are more profound. In addition to lymphocytic invasion of the walls of small vessels in the papillary dermis, there is erythrocyte extravasation and edema of endothelial cells, with luminal narrowing.The suppressive effect of tetracycline on PLVA2 in some patients and presence of