==== Front Ann Saudi MedAnn Saudi MedAnnals of Saudi Medicine0256-49470975-4466King Faisal Specialist Hospital and Research Centre 10.5144/0256-4947.2008.140aasm-2-140aLettersSeasonal variation of appendicitis in northern Saudi Arabia Sanda Robert B. aZalloum Mohammed bEl-Hossary Mustapha aAl-Rashid Fowaz bAhmed Omer aAwad Anas aFarouk Ashraf aSeliemt Salah aMogazy Kasem a a Surgery Department of Hail General Hospital, Hail, Saudi Arabia b Surgery Department of King Khalid Hospital, Hail, Saudi ArabiaCorrespondence and reprints: Robert B. Sanda, FRCSI, robeesanda@yahoo.comMar-Apr 2008 28 2 140 141 Copyright © 2008, Annals of Saudi Medicine2008This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. ==== Body To the Editor: We have noted apparent discrepancies in the monthly number of appendectomies performed in our hospitals, which we decided to verify. Retrospectively, we analyzed all cases operated on with a discharge diagnosis of acute appendicitis in Hail General Hospital (HGH) and King Khalid Hospital (KKH), Hail, Saudi Arabia, from January 2000 to December 2006. These two hospitals treat nearly all cases of appendicitis in this city. Negative appendectomies and cases with intra-operative findings of other pathology with similar clinical features as acute appendicitis were excluded. A total of 3159 cases met our inclusion criteria comprising of 1629 and 1530 cases from HGH and KKH, respectively. We used the chi-square statistic for analysis with probability less than 5% set for statistical significance. We observed a low in the number of appendectomies in the winter months of December to February and a high in the spring months of March to May (Figure 1). These differences proved to be significant (P<.001). Our finding agrees with published reports from the USA,1 Canada,2 Italy,3 Israel4 and Russia5 where appendicitis had a peak incidence in the summer months with a winter nadir. The reason for these trends has been the subject of conjecture. While many believe that the etiology of acute appendicitis is multi-factorial,5 none have been able to show conclusively its precise etiology. Gender and ethnic trends have been observed1,2,6 and offered as proof the role of genetic factors. Diet, hygiene, the climate and infective agents,7 on the other hand, have been proposed as environmental factors that may play roles in the etiology of acute appendicitis. The increase in incidence of acute appendicitis in the spring months in our locality coincides with the onset of the sandstorm season in the Arabian peninsula, characterized by strong winds blowing across the desert bringing dust that hangs in the air. We are inclined to believe that the weather change has something to do with our observation. Our hypothesis has found credence in the work of Kwasi et al8–10 who have studied the health impact of this climatic phenomenon in the city of Riyadh. They amply demonstrated the strong pathogenic potential of date palm pollen as an allergen and isolated viable microbial pathogens and pollen allergens in sandstorms.11 Further support for our hypothesis comes in the recent paper by Bellester et al,12 who found a significant association between tonsillectomy and appendectomy among Spanish patients. We suggest that the intense challenge to the mucosa-associated lymphoid tissue from allergens, bacteria and viruses, as occurs during the sandstorm season, may be causally related to acute appendicitis and would explain the seasonal variation we have noted. By implication we expect that preventive strategies and adequate treatment of respiratory tract infections and allergies affecting the airway among children should prevent some cases of acute appendicitis. Figure 1 Bar diagrams showing the combined monthly number of cases of appendicitis Hail General Hospital and King Khalid Hospital, Hail from 2000 to 2006 inclusive. ==== Refs REFERENCES 1 Luckmann R Davis P The epidemiology of acute appendicitis in California: racial, gender, and seasonal variation Epidemiology 1991 9 2 5 323 30 1742380 2 Al-Omran M Mamdani M McLeod RS Epidemiologic features of acute appendicitis in Ontario, Canada Can J Surg 2003 8 46 4 263 8 12930102 3 Gallerani M Boari B Anania G Cavallesco G Manfredini R Seasonal variation in onset of acute appendicitis Clin Ter 2006 Mar-Apr 157 2 123 7 16817501 4 Freud E Pilpel D Mares AJ Acute appendicitis in childhood in the Negev region: some epidemiological observations over an 11-year period 1973–1983 J Pediatr Gastroenterol Nutr 1988 Sep-Oct 7 5 680 4 3183871 5 Khaavel’ AA Birkenfeldt RR Nature of the relation of acute appendicitis morbidity to meteorological and heliogeophysical factors Vestn Khir Im I I Grek 1978 4 120 4 67 70 6 Petroianu A Oliveira-Neto JE Alberti LR Comparative incidence of acute appendicitis in a mixed population, related to skin color Arg Gastroenterol 2004 Jan-Mar 41 1 24 6 7 Martin DL Gustafson TL A cluster of true appendicitis cases Am J Surg 1985 11 150 5 554 7 2998216 8 Kwaasi AAA Tipirneni P Harfi H Parhar RS Al-Sedairy ST Date palm (Phoenix dactylifera L) is a potent allergen Ann Allergy 1992 68 78 9 Kwaasi AAA Parhar RS Tipirneni P Al-Sedairy ST Characterization of antigens and allergens of date palm (Phoenix dactylifera L) pollen: immunological assessment of atopic patients using whole extracts or its fractions Allergy 1992 47 535 44 1485659 10 Kwaasi AAA Tipirneni P Harfi H Al-Sedairy ST Major allergens of the date palm (Phoenix dactylefira L) pollen: identification of IgE binding components by ELISA and immunoblot analysis Allergy 1993 48 511 8 8238810 11 Kwaasi AAA Parhar RS Al-Mohanna FAA Harfi HA Collison KS Al-Sedairy ST Aeroallergens and viable microbes in sandstorm dust Allergy 1998 53 255 65 9542605 12 Andreu Ballester JC Ballester F Colomer Rubio E Millan Scheiding M Association between tonsillectomy, adenoidectomy, and appendicitis Rev Esp Enferm Dig 2005 3 97 3 179 86 15839812