What causes itching and does scratching help?

Itchy Skin: Causes of itching include: dry skin, internal diseases, nerve disorders, irritation and allergic reactions, drugs, pregnancy, skin conditions and rashes. Itchy skin that isn't accompanied by other obvious skin changes, such as a rash, is most often caused by dry skin (xerosis). Dry skin usually results from environmental factors that you can influence. These include hot or cold weather with low humidity.