Why do I get bumps on my hands when it gets warm out?

Eczema? You may have sweaty palms in the heat of the year. This can cause small blisters on the palms of the hands and along th sides of the hands and fingers and is called dishidrosis or dishidrotic eczema. This ususally responds to medium strength to high potency topical steroid creams/ointments. See your pcp or dermatologist. Keep the hands as dry as possible.