Non-interventional Study to Assess the Tolerability and the Safety Profile of SCIT Therapy With Acarovac® Hausstaubmilbe

House dust mite sensitized Patients receive increasing doses of subcutaneous immunotherapy with Acarovac. During the up-dosing phase, patients will receive 4 injections in 1-2 week intervals with increasing allergen amount up to the individual maximum tolerable dose. After reaching the individual maximum tolerable dose patients will receive one maintenance dose in a 4 - 8 week interval.