Itching at night, also known as nocturnal pruritus, happens for several reasons related to how the body functions differently at night. One major factor is the body's circadian rhythm, which regulates hormones and chemicals like cortisol, melatonin, cytokines, and prostaglandins; their levels change at night and can increase skin inflammation and itching. Additionally, body temperature rises slightly at night, and skin loses more moisture, both of which can trigger itchiness. Psychological factors also play a role—during the day, distractions limit the perception of itch, but at night, the quiet and stillness make it more noticeable. Common causes include dry skin, eczema, allergic reactions, bug bites (like bedbugs or scabies), and sometimes underlying health conditions such as liver disease or thyroid issues. Environmental factors such as dry air and certain detergents can worsen the sensation as well.

In summary, night itching is often due to natural changes in body chemistry and environment, but persistent or severe itching may indicate a medical condition needing attention.