Mite and cockroach sensitisation in patients with allergic rhinitis in the Free State

Studies in patients with allergic rhinitis living in the Free State have showed grass pollens to be the predominant allergens, with house-dust mite sensitisation being less prevalent than in the coastal areas and a low rate of sensitisation to the storage mite Lepidoglyphus destructor. No studies have been conducted on sensitisation to the other storage mites, spider mites or cockroaches. We aimed to determine the prevalence of sensitisation to various house-dust mites, storage mites, spider mites and cockroaches in patients with allergic rhinitis living in the Free State.

Fifty consecutive patients with allergic rhinitis attending the ear, nose and throat clinic at Universitas Hospital underwent skin-prick testing and/or ImmunoCAP RAST testing for common aero-allergens, house-dust mites, storage mites, spider mites and cockroaches.

Forty-six per cent of patients were sensitised to one of the house-dust mites, with house mite sensitisation being significantly more common in patients who had previously lived at the coast. Storage mites were not common aero-allergens, while 46% of patients were sensitised to the spider mite Tetranychus urticae. Blatella germanica was the cockroach species to which patients were most commonly found to be sensitised on ImmunoCAP RAST testing, with 38% of patients being sensitised to this aero-allergen.

House-dust mites, T. urticae and the cockroach B. germanica appear to be important aero-allergens in the Free State. Storage mite sensitisation is not common.