In summer, the water at the beaches can contain bird parasites that are so small that they are not visible. When bathed, they can drill into the skin a few millimeters before dying, resulting in a harmless reaction with itchy rash.
It can itch in different places on the body and the itching may be due to various things, such as dry skin or infection. Read more here about causes of itching.
Scabies is a small spider-like animal, a mite. The scavenger enters the skin and makes passages in the outer layer of skin where they lay their eggs. The most common symptom is it itching, especially at night. Scabies are usually treated with medicines that you apply to your skin. Scabies is usually transmitted through close body contact.