Intranasal administration of corticosteroids: patients, administration techniques and instructionsIntranasal corticosteroids (INCs) are used in allergic rhinitis and suppress allergic inflammation in the nasal mucosa. Adequate administration of INCs has received limited attention in clinical practice and scientific literature, whilst research about correct administration of asthma inhalers is widely available and has become a major focus area. Corine Rollema approaches different aspects related to treatment with INCs in her thesis. This thesis shows that there is sufficient research about the efficacy and safety of INCs. However, efficacy and safety may also depend on nasal particle deposition. According to Rollema's research it remains unclear whether, and to what extent, a set of administration variables affect deposition.In addition, patients apply certain habits for administration of INCs based on different instructional sources. The conducted research shows that various instructional sources including instructions in patient information leaflets, given by healthcare providers and in videos on YouTube® are incomplete, non-uniform or of insufficient quality.This thesis describes what characterizes current INC-users and what side effects may occur in clinical practice. In addition, the administration technique of patients was analyzed and knowledge about the administration of INCs was found to be insufficient. To successfully instruct children about the administration of INCs, this thesis indicates that an instructional video for children is an effective tool to improve administration.Rollema hopes that further research about the administration of INCs will lead to a combination of a well-substantiated administration technique and a patient-tailored instruction and evaluation, which may lead to optimal treatment with INCs.