Patients appear knee long blisters, generally common clinical reasons are mainly the following situations. First, the knee accidentally fall can cause local soft tissue contusion injury, and cause local tension blisters. At this time can be through the local external 0.5% vitality iodine gauze, syringe suction out of the blister within the cystic fluid to reduce local tension, oral bruise pills and other drugs. Most of the patients 3-5 days after the local soft tissue injury can be faster recovery, blisters at the knee can be self-absorbed, will not cause serious effects. Second, patients with allergic reactions to the skin at the knee can also cause local blister formation, and may even be accompanied by redness, swelling and pain. Patients can reduce the allergic reaction by rubbing Bactroban ointment, glycerite lotion, oral loratadine and other drugs to promote the faster absorption of knee blisters.