Final answer:
The use of a spacer with a fluticasone inhaler for asthma decreases the risk of developing oral candidiasis, which is an adverse effect of the medication.
Step-by-step explanation:
When teaching a child with a new prescription for a fluticasone inhaler to treat chronic asthma, it is important to include that the use of a spacer can decrease the risk for certain adverse effects of the medication. The correct answer to which adverse effect the spacer decreases the risk for is B) Oral candidiasis. A spacer is a device that attaches to the inhaler and helps to deliver medication more effectively to the lungs, which reduces the medication's contact with the mouth and throat, therefore decreasing the likelihood of developing oral candidiasis.