Final answer:
Itching can be caused by various factors, including allergic reactions. Antihistamines, opioids, neurotransmitters, and corticosteroids are all pharmacological mediators that can influence the sensation of itching.
Step-by-step explanation:
The pharmacological mediators of itching include antihistamines, opioids, neurotransmitters, and corticosteroids. Each of these plays a different role in the sensation of itching. Antihistamines block histamines, which are released during allergic reactions and can cause itching. Opioids can both induce and reduce itching, depending on the receptor types they activate. Neurotransmitters may be involved in signaling pathways that relay itch information to the brain. Lastly, corticosteroids are used to reduce inflammation, which can help alleviate itching associated with various dermatological conditions.