Seasonal variation of acute necrotising ulcerative gingivitis in South Africans.

OBJECTIVES To examine seasonal variations in the presentation of acute necrotising ulcerative gingivitis (ANUG) in a previously unstudied population in Cape Town, South Africa. DESIGN A descriptive study of all presenting cases of ANUG at a health center over 6 years; patients were examined at one point in time. SETTING A clinic-based cross-sectional study was carried out among patients presenting routinely to the oral medicine clinic at the University of the Western Cape. Patients at this clinic were mostly colored and black people, and were of low socioeconomic status. SUBJECTS AND METHODS All patients presenting to the periodontal clinic were examined during the period from 15 March 1992 to 15 March 1998 and interviews were conducted. A comprehensive clinical intra-oral and peri-oral examination was carried out using a dental mirror and blunt probe by three trained calibrated dental examiners. The minimum criteria for inclusion as an ANUG patient were painful, bleeding gums with irreversible destruction of the interdental papillae (cratering) and marginal gingiva. Patients with multiple small ulcerations not restricted to the gingiva, but including other oral sites such as the tongue and buccal mucosa were diagnosed as herpetic stomatitis. Other distinguishing characteristics of ANUG included presence of a pseudomembrane, odor, a strange taste in the mouth, and hypersalivation. Swabs and biopsies taken to verify the diagnosis when necessary. If there was any doubt as to the diagnosis of the lesion it was not included among the ANUG cases. MAIN OUTCOME MEASURE Presence of ANUG. RESULTS Among the 19944 patients presenting for periodontal treatment, 684 were found to have ANUG. The ANUG patients consisted of 58% males; 73% of the ANUG patients were between the ages of 5 to 12 years. The majority of ANUG patients presented during the summer (55.4%), 27.7% in autumn and 8.4% during both winter and spring. Significant differences were evident between the numbers seen during the different seasons. CONCLUSIONS This study demonstrated a significant seasonal variation in the occurence of ANUG in Cape Town, South Africa.