Undifferentiated systemic connective tissue disease-"overlap' in Zimbabwe.

OBJECTIVE: To define the clinical characteristics of the overlapping, undifferentiated systemic connective tissue disease in one of the tropical African countries. DESIGN: A descriptive retrospective study of records of patients registered on a special rheumatology clinic between 1989 and 1994. SETTING: Harare Central Hospital Rheumatology Clinic, Zimbabwe. SUBJECTS: All registered patients with systemic connective tissue diseases. MAIN OUTCOME MEASURES: Numbers of patients, laboratory and clinical features of undifferentiated overlapping connective tissue disease. RESULTS: The distribution for those who satisfied internationally accepted criteria for classification/diagnosis were: 48(52.8pc) rheumatoid arthritis (RA), 17(18.7pc) systemic lupus erythematosus (SLE), 10(11pc) juvenile chronic arthritis (JCA), four (4.4pc) polymyositis/dermatomyositis (PMD) and 11 (12.1pc) overlapping connective tissue disease (overlap) and one unclassified disease. No pure progressive systemic (PSS) was registered. Among the overlap patients, five had SLE-RA, three SLE-PSS and one each for SLE-RA-PSS, RA-PSS and SLE-PDM overlapping clinical features respectively. In two patients with SLE-PSS, the criteria of each of the individual connective tissue disease were satisfied. Similarly, in one patient with SLE-RA and another with RA-PSS features, the criteria of individual disease were also satisfied. CONCLUSION: In undifferentiated overlapping connective tissue diseases-overlaps occur in tropical Africa, the SLE-RA overlapping features predominate and are moderately severe diseases.