an investigation into the nature and existence of the cicada insect The most common cause of itching is a primary skin disease such as eczema, urticaria, lichen planus, psoriasis, dermatitis herpetiformis, insect bites and scabies systemic causes of itch include pregnancy, chronic renal failure, cholestasis, thyroid dysfunction, haematological disorders, iron deficiency and internal malignancy [6].