I have itchy arms and legs at night before sleep, but not when i lie in my bed in the mornings or evenings, no bumps or insect bites, what can it be?

Itchy: Do you have dry skin? This is one cause. Occasionally itchiness develops at night when the body temperature rises. You can prevent this by taking benadryl( may make you drowsy) or Claritin (loratadine). Overactive thyroid or polycythemia(excess red blood cells) are rarer causes. Your physician can evaluate you and order any appropriate tests.