Since Adamson's1 report in 1920 postulating a relation between keratosis blennorrhagica and psoriasis arthropathica, various clinicians have felt that the two conditions are identical. Adamson based his contention on the following four points. First, cases of arthropathic psoriasis are observed in which the lesions on the palms and soles strikingly resemble those of gonorrheal keratosis. Second, in many cases of keratosis blennorrhagica there are lesions on the limbs and trunk which are indistinguishable from those of psoriasis. Third, there are cases in which it is difficult to make a definite diagnosis between the two. Finally, there is a striking similarity in the histologic architecture of the two conditions.
No serious objections can be raised against the arguments advanced, but the conclusion drawn appears erroneous at this date. With the advantage of twenty years of further study of the subject, most dermatologists feel that the two conditions are separate entities.
EPSTEIN E. DIFFERENTIAL DIAGNOSIS OF KERATOSIS BLENNORRHAGICA AND PSORIASIS ARTHROPATHICA. Arch Derm Syphilol. 1939;40(4):547–559. doi:10.1001/archderm.1939.01490040028004