The house dust mite, the spores of the mould, humours, animal fur and feather are responsible for the triggering of ’recurring’ symptoms of the perennial rhinitis which exist throughout the whole year. Symptoms. Symptoms are the same as ones of seasonal allergic rhinitis, however nasal obstruction and inflammation of the sinuses (sinusitis) are frequent complications.

Most complaints are caused by the house dust mite, which in real life cannot be found in all house dust, but exclusively in the bed. Studies have shown that the dust found in the mattress includes dust mites in an over 100% higher concentration that dust found on the floor.

Mite only live and reproduce on places (producing allergens), where the following conditions prevail:

• Plenty of food available (they mostly eat necrosed epithelial cells).
• Permanent temperature, around 20 °C, humidity ranging between 60-80%.
• Lack of sunlight (sunbeams destroy mites).

Beds offer an ideal living environment for the mite as they contain their food in high numbers (epithelial cells), and due to the moisture and heat given off by the human body, temperature and humidity conditions are optimal. Also, lack of sunlight is fully secured.

The metabolism product of the mite named Dermatophagoides pteronyssinus, the same allergen which induces house dust sensitivity, is one of the most well-known and widespread allergens among the allergens inducing chronic persistent allergic rhinitis. Symptoms of allergy are well-known: sneezing, rhinorrhea, nasal itching, nasal obstruction, itching of the eyes and the palate.

Complaints can be caused by house dust mite allergy in the following cases:

• Some sort of allergic disease has already occurred within the family.
• Allergic disease are more likely to appear in firstborn children.
• Allergy is more frequent in boys.
• In case an allergy-originated disease has already appeared in the patient.
• Symptoms are always related to a given place (e.g. bedroom).
• Nasal obstruction paired with a thicker secretion appears at night-time.
• Watery rhinorrhea lasting for more than 7-10 days.
• Nasal complaints appear without fever.
• Symptoms are not recovered even following an antibiotic treatment.