The common clinical causes of itchy and swollen palmar pachyderm include pachyderm muscle strain, angioneurotic edema, and so on. 1. Intermuscular strain: Intermuscular strain plays an important role in thumb activity, if the thumb activity is too frequent or fatigue, may cause intermuscular strain edema, and there will be a non-infectious inflammatory reaction, which will cause stimulation of the peripheral nerves, the clinical manifestations of the affected area itching, pain and so on. 2. Angioneurotic edema: if the allergic people, the palmar intertriginous part of the hand after contact with allergic substances or stimulation, may induce the body’s allergic reaction, resulting in increased vascular permeability of the part, nerve excitation or damage, clinical manifestations of the part of the swelling, redness, itching, pressure and pain, and so on. There are many reasons for this symptom, if the symptoms persist, it is recommended that people with the disease should go to the hospital for a clear diagnosis through examination and targeted treatment.