Final answer:
The complaint of itching may be associated with the use of azelaic acid, which is used to treat skin conditions like acne and rosacea.
Step-by-step explanation:
The clinic nurse who is assessing a client taking azelaic acid might find that the client has complaints that can be associated with its use. Among the options provided, the complaint of itching (D) may be associated with the use of azelaic acid. Azelaic acid is a medication generally used to treat skin conditions such as acne and rosacea. Itching can occur as a local skin reaction due to its application. Fatigue, nausea, and headache are less commonly related to the topical use of azelaic acid, and they might be symptoms of various other conditions or medications.