There are many reasons why the palms of the hands grow small grains like small blisters, such as sweating herpes, hand, foot and mouth disease, ringworm and so on. 1. Sweat herpes: may be related to mental factors, local infection, allergy or irritation, etc., can cause the palm of the hand long small grains like small blisters phenomenon, while the local will be accompanied by obvious itching. 2. hand, foot and mouth disease: hand, foot and mouth disease is mostly due to viral infections, can cause the palm of the hand long small grains like small blisters, accompanied by the oral cavity and feet are small blisters, accompanied by pain. 3. ringworm: ringworm is a fungal infection, not only will cause the palm of the hand long small grains like small blisters, at the same time will be accompanied by local flaking and other phenomena. There are many reasons why the palms of the hands are so long as small grains like small blisters, and it is recommended to consult a doctor in a timely manner after the symptoms appear, take standardized treatment according to the doctor’s instructions, and not to ignore the symptoms, and take it lightly.