What is the prevalence of allergic fungal sinusitis (AFS)?

Updated: Mar 16, 2018
  • Author: John E McClay, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Approximately 5-10% of patients affected by chronic rhinosinusitis actually carry a diagnosis of allergic fungal sinusitis (AFS). Atopy is characteristic of the disease; approximately two thirds of patients report a history of allergic rhinitis, and 90% of patients demonstrate elevated specific IgE to one or more fungal antigens. Approximately 50% of patients in a series by Manning et al had asthma. No linkage to aspirin sensitivity has been established.

Incidence of allergic fungal sinusitis (AFS) appears to be impacted by geographic factors. Review of world literature reveals that most sites reporting cases of allergic fungal sinusitis (AFS) are located in temperate regions of relatively high humidity. However, incidence of allergic fungal sinusitis (AFS) varied remarkably based on the location of reporting sites. Allergic fungal sinusitis (AFS) in the United States was encountered most commonly within the Mississippi basin, the Southeast, and the Southwest. The reason for this geographic difference remains unexplained.

Allergic fungal sinusitis (AFS) is most common among adolescents and young adults; the mean age at diagnosis is 21.9 years. The male-to-female (M/F) ratio of allergic fungal sinusitis (AFS) differs slightly between published reports but is believed to be equal when all ages are evaluated together. A literature review of 98 cases in the 1980s and early 1990s from 29 published journal articles reported an equal M/F incidence. A review by the author and colleagues of 151 patients at the University of Texas (UT) at Southwestern also revealed an equal M/F ratio, with ages ranging from 5-75 years. [9]

However, the M/F ratio may be age dependent and different in children and adults. In the review of patients at UT Southwestern, in children, males dominated (M/F ratio 2.1:1; average age, 13 y), and in adults, females dominated (M/F ratio 1:1.4; average age, 36 y). When evaluating the average ages and sex ratios of other studies, series with younger average ages are more likely to have a male predominance. The average ages in the male-dominated series were 25 and 27 years, while the average age in the female-dominated series was 33 years. The only other pediatric series consisted of 10 patients and had an M/F ratio of 1.5:1, with a mean age of 13.6 years. Interestingly, when 2 series of patients from a single institution were reviewed over time, an early study had an M/F ratio of 1.5:1, with an age range of 13-51 years (average age, 27.5 y), and a later review had an M/F ratio of 1:1.4, with an age range of 13-69 years (no average age given).


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