Hello and hope you are doing well.
The commonest cause of itching and swelling of hands is any allergy. On exposure to allergens our immune system responds by secreting histamines in larger amounts. This can lead to swelling. Contact dermatitis is a possibility. The allergen can be anything from bed linen,mattress,dust etc.In few cases it may be difficult to detect the allergen .Besides inflammation of the joints, hand swelling and pain can be seen in most arthritis types like polycythemia Vera, systemic lupus erythematosus and fibromyalgia. Swollen hands can be due to carpal tunnel syndrome or Buerger’s disease. Hand injuries, fractures, insect bite, kidney or liver diseases, blood disorders are other few possibilities. These possibilities are based on the information provided by you. For accurate diagnosis a complete clinical evaluation and work up is important. Tests like complete blood counts, RA factor, ESR, Xray hands and other tests depending on the suspected cause may be needed. I sincerely hope it helps.
Take care and good luck!