Lumbar spine fracture bed rest for 2~3 months down legs appear red spots may be the emergence of allergies, allergic purpura and other reasons. 1. Allergy: may be lumbar fracture or housing during the leg contact with allergic substances, easy to make the skin itchy and red spots of symptoms, accompanied by redness and swelling or red bumps and other symptoms. 2. Anaphylactic purpura: belongs to the systemic small blood vessel allergic reaction inflammation, but the lumbar spine fracture bed rest patient body immune disorders or allergens infection and heredity and other reasons, easy to make the legs appear measles and red spots and red pimples and other symptoms. It is necessary to go to the hospital in time to improve the allergy antibody and medical history and physical examination and other related examinations, which is conducive to the cause of the disease and condition, and speed up the recovery of the body.