Itchy hands

I'm a 42 year old female. A few days ago I noticed slight itching intermittenly all over but no rash whatsoever.  Also noticed my hands and feet feel swollen/tight, but do not look swollen, and itch.  When walking it felt as though there was a knot on the ball of my foot but nothing visible.  Itching comes and goes as does the swollen feeling.  I took Benadryl yesterday and did notice some relief.  No symptoms this morning but noticed the feeling coming back again around 4pm today so I took more Benadryl.  Any idea what might be wrong?  Thanks.