Skin becomes dry and itchy when it loses moisture faster than it can replace it, often in winter, in low-humidity or air-conditioned environments, or after frequent hot showers and harsh soaps that strip natural oils. Skin also tends to get drier with age. Regular use of a fragrance-free moisturiser (emollient), shorter lukewarm showers and gentle cleansers usually help a lot.
Persistent or very itchy skin may be eczema or contact dermatitis, especially if there are red, inflamed or cracked patches. Less commonly, generalised itch without an obvious rash can be linked to thyroid problems, iron deficiency, liver or kidney issues, or certain medications, which is worth checking if it does not settle.
See a doctor or pharmacist if itch disrupts your sleep, the skin is broken or infected (warm, weeping, increasingly red), or self-care does not help within a couple of weeks. Seek prompt care for itch with jaundice, significant weight loss or widespread rash. This is general information only.