Product information:

Purotex is a textile treatment that uses five 100% natural bacteria or probiotics, selected for their ability to clean up house dust mite allergen along with other allergen types.

Study design:

• Placebo-controlled: the effect of the Purotex impregnated mattress and pillow covers will be compared to untreated, classical bedding covers (placebo).
• Cross-over design: There will be 2 'treatment' arms. One arm (Arm 1) in which the subjects will first use the Purotex impregnated covers (Set A=Purotex) during 2 months (=period A) and, after a wash out period of 1 month, the untreated covers (set B=placebo) during 2 months (=period B). In the second arm (Arm 2), the subjects will first use the untreated set (set A=placebo) and, after a wash out period the Purotex impregnated covers (set B=Purotex).
• Randomized: The subjects will be randomly assigned to one of the 2 treatment arms.
• Double blind: both the subjects and the investigators will not know to which treatment arm the subjects are assigned.

Study hypothesis:

We want to investigate:

• if there is a reduced concentration of HDM allergen in Purotex covers compared to untreated covers in real life
• if patients with allergic rhinitis to house dust mite use the Purotex covers, they experience an improvement of their quality of life and sleep, and an improvement of their allergic symptoms and global discomfort

Inclusion Criteria:

• Subjects must be willing to give/sign informed consent
• Subjects (male or female) must be at least 18 years old and maximum 65 years old at screening
• Clinical history of allergic rhinitis for at least 1 year
• Positive skin prick test for D. Pteronyssinus ± D. Farinae
• Positive nasal provocation test with the house-dust-mite allergen
• Specific IgE: Unicap positive to D. Pteronyssinus (d1) and D. Farinae (d2) (> 0.7U/ml)
• VAS score for global discomfort caused by nasal- or other allergic symptoms during the previous 4 weeks ≥ 5.
• The concentration of Der p1 in the dust collected from own bedding (mattress and pillow), measured by ELISA is above the detection limit (≥ 0.488 ng/ml).

Exclusion Criteria:

• Patients sensitized to animals should not be included if they are symptomatic upon exposure and regularly exposed to animals: positive SPT to pets and pets at home
• Patients with an allergy to tree pollen (symptoms during the season + positive skin prick test) should not be included
• Subject pregnant or lactating
• Completed allergen specific immunotherapy (SCIT or SLIT) with HDM within the last 5 years
• SCIT or SLIT during the study period
• Regular use of oral corticosteroids for exacerbations of asthma
• Daily use of oral corticosteroids
• Daily use of cyclosporine or other immunosuppressant drugs
• Regular use of antibiotics
• History of anaphylactic reaction to an allergen
• Severe general diseases (especially cardiopulmonary disease with reduced lung capacity)