The sole and essential symptom is itchiness, usually more or less paroxysmal, and worse at night. There are no primary structural lesions, but in severe and persistent cases the parts become so irritated by continued scratching that secondary lesions, such as papules and slight thickening and infiltration, may result. It is much more common in advanced life—pruritus senilis. In such cases, as well as in those cases in younger and middle-aged individuals in which the itchiness develops at the approach of cold weather and disappears upon the coming of the warm season (pruritus hiemalis), the pruritus is usually more or less generalized, although not infrequently in the latter the legs are specially involved.
In some individuals an attack of pruritus, of variable intensity, lasting from five to thirty minutes, comes on immediately after a bath (bath-pruritus). It is usually confined to the legs from the hips down.
Is pruritus always more or less generalized?
No; not infrequently the itching is limited to the genital region (pruritus scroti, pruritus vulvæ) or to the anus (pruritus ani).
To what may pruritus often be ascribed?
To digestive and intestinal derangements, hepatic disorders, the uric acid diathesis, gestation, diabetes mellitus, and a depraved state of the nervous system.
Pruritus vulvæ is at times due to irritating discharges, and pruritus ani occasionally to hemorrhoids and seat-worms.
Is there any difficulty in the diagnosis of pruritus?
No. The subjective symptom of itching without the presence of structural lesions is diagnostic. In those severe and persistent cases in which excoriations and papules have resulted from the scratching, the history of the case, together with its course, must be considered. Care should be taken not to confound it with pediculosis. In this latter the excoriations usually have a somewhat peculiar distribution, being most abundant on those parts of the body with which the clothing lies closely in contact. (See Pediculosis corporis.) In pruritus of the genitocrural region the possibility of pediculi being the cause must be kept in mind; an examination of the parts for the parasite or for ova (attached to the hairs) would prevent error. (See Pediculosis pubis.)
What prognosis would you give in pruritus?