The national campaign against syphilis is doing much to arouse in physicians and especially in the laity a syphilis consciousness. The campaign, while it seeks to draw attention to all forms of syphilis, stresses particularly the detection and management of the highly infectious primary and secondary manifestations. Syphilis not only simulates other diseases in its late manifestations but the secondary eruption may imitate many other dermatoses. Many persons have now learned that secondary syphilis is a generalized eruption and we have been impressed during the past two years by an increasing number of persons who, on discovering the presence of pityriasis rosea on their bodies, have come to us for assurance that they do not have syphilis.
Pityriasis rosea is a harmless and clinically unimportant disease per se, but, although uncommon (an incidence of about 5 per 1000 skin diseases1), it takes a prominent place in the differential diagnosis of secondary syphilis with which it may be confused. The acute generalized maculopapular and papular types which occasionally appear on the face and genitalia at first sight do look formidable. If the busy physician makes only a superficial examination or is unfamiliar with the fundamental characteristics of the disease, he may be led to an erroneous diagnosis of syphilis. An intimation of such a diagnosis to the patient may do irreparable damage to both the patient himself and his domestic happiness as well as cause the physician much embarrassment.
The superficial, cutaneous, fungous infections occupy a position parallel with that of. . .