Baby hand swelling may be mosquito bites, local allergies, trauma and other causes. 1. Mosquito bites: due to the baby’s skin is more delicate, mosquito bites, there may be localized swelling, generally unilateral hand swelling, more also accompanied by symptoms of itching. 2. local allergy: if the baby hand contact with allergic substances, can cause local vasoneurotic edema, resulting in baby hand swelling. 3. Trauma: the baby’s hands have a history of trauma, such as falling down when the hand first hit the ground, will lead to the baby’s hands swollen, more accompanied by pain and other symptoms. Baby hand swelling, may also be caused by other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, give targeted treatment or standardized treatment.