relapse

a new exacerbation of a disease during remission after an apparent recovery. In the case of a latent chronic infection, for example, brucellosis, pneumonia, and erysipelas, a relapse may be caused by inadequate immunity, chilling, or the supervention of a secondary infection. It may also be caused by a faulty diet, for example, with colitis, or by the cyclical nature of the disease itself (malaria, relapsing fever). The pathogenic microflora of the body is usually activated as a result of a relapse. A repeated infection caused by the same microorganisms is called a reinfection.

The pathogenesis of a relapse of a noninfectious disease is caused by shock, for example, with eczema, by vascular disorders, by regular malignant growth, and by inadequate treatment, for example, by the incomplete removal of a tumor. The pathogenesis of a relapse is sometimes unknown, for example, with familial Mediterranean fever and schizophrenia.

The clinical symptoms of a relapse may resemble or differ from the onset of a disease as a result of both the nature of the disease and the prescribed treatment. A relapse is sometimes more severe than the first attack of a disease and is more difficult to treat, as in the case of a relapse of acute leukemia. A relapse may be accompanied by complications, for example, intestinal bleeding in typhoid. Relapses are common to some diseases, for example, chronic dysentery. Treatment and preventive methods for relapses are usually the same as for the original disease.