Prevalence and determinants of allergic diseases in a Congolese population

Allergic rhinitis (AR) is increasing worldwide, but little is known about AR in Africa. We aimed to establish the prevalence of AR and related allergic diseases, to classify AR according to the Allergic Rhinitis and Its Impact on Asthma (ARIA) guidelines, and to determine factors associated with allergy in Congo.

We conducted a cross-sectional clustered survey of the population of 8 randomly chosen health zones of Kinshasa. Information was collected on demographics, home environment, participant characteristics, atopic history, and allergic symptoms. Skin-prick testing (SPT) was done.

Of 1508 screened individuals, 1412 (5-83 years of age) were interviewed and 1005 underwent SPT. Of the participants, 65.6% and 34.4% lived in urban and rural areas, respectively. Mean (± standard deviation [SD]) of age was 29 (±16) years and 52% were female. The 12-month prevalence of rhinitis, rhinoconjunctivitis, wheeze, and skin itch-rash was 30.8%, 24.4%, 15.4%, and 6.2%, respectively. Rhinoconjunctivitis and wheeze were more prevalent in urban than rural individuals. Of skin-tested respondents, 23.2% showed positive results, with mainly Dermatophagoides pteronyssinus and cockroach being involved. AR and non-AR prevalence was reported in 13.9% and 27.9%, respectively. Of AR individuals, 59.7% and 48.0% expressed moderate to severe and persistent symptoms, respectively. Independent determinants of having any allergic diseases in multivariate analysis were active smoking, presence of cockroach in home, history of atopy in siblings, personal history of atopy, using straw or herb mattress, and positive SPT responses.

This study revealed a high prevalence of allergic diseases in Congolese individuals. It is important to increase awareness toward allergic disorders and to ensure adequate management.