Characteristics of atrophic rhinitis in Thai patients at the Siriraj Hospital.

The common characteristics of primary atrophic rhinitis were studied in 46 Thai patients. From history and demographic data the female to male ratio was found to be 5.6 to 1. The significance of environmental factors was supported by the findings that 69.6% were people from rural areas and 43.5% were industrial workers but a hereditary factor has not been confirmed. The results of the blood tests did not elucidate iron deficiency anemia or nutritional deficiency as the cause of primary atrophic rhinitis. However, all nasal swab cultures yielded pathogenic organisms where Klebsiella species especially, K. ozaena, were the most common bacteria isolated which were 100% susceptible to cephalosporins. This finding together with the evidence of sinusitis seen in 58.7% of either plain x-rays or CT scans, was suggestive of the important role of infection in atrophic rhinitis. Atrophic change of the mucosa and bone with widening of the nasal cavity were constant findings in the CT scans but the developmental anomaly of the maxillary antrum was found in only 15.2%. The histological study showed characteristic changes especially squamous metaplasia and 80% of the cases were compatible with the Type II histopathological classification, i.e. vasodilatation of the capillaries. The mucociliary function was proven to be impaired in accordance with the loss of cilia. The evidence of Type I allergy demonstrated by skin testing, which was obvious in 85%, is highly suggestive of allergic/immunologic disorders. Although many factors have been cited previously as the possible cause of primary atrophic rhinitis, the common characteristics found in our patients indicate that only bacterial infection, environmental factors and allergic/immunologic disorders could be one or more of its multifactorial etiology and should be further investigated.