Left-sided lower back pain can be caused by numerous conditions or injuries. According to the American Academy of Family Physicians, although almost everyone experiences low back pain at some point in their lives, the quality and location of low back pain varies considerably from one person to the next. Some people may have low back pain on both sides of the body, whereas other people may experience back pain on the left or right side only.
Psoriatic Arthritis
Psoriatic arthritis can cause left-sided lower back pain. According to the Mayo Clinic website, psoriatic arthritis is a type of arthritis that occurs in some people who have psoriasis. Psoriasis is a serious autoimmune disease that's characterized by scaly, red patches on the skin. In most cases, psoriasis manifests before psoriatic arthritis, although the reverse can be true in some individuals. Common signs and symptoms associated with psoriatic arthritis include pain and stiffness in the involved joints, swollen joints and joints that are warm to the touch. The Mayo Clinic website states that there are five types of psoriatic arthritis, which are categorized based on their specific pain pattern: joint pain on one side of the body, joint pain on both sides of the body, joint pain in the fingers, spinal pain and destructive arthritis or arthritis mutilans. According to the Mayo Clinic website, there is currently no cure for psoriatic arthritis.
Pelvic Inflammatory Disease
Pelvic inflammatory disease, or PID, can cause left lower back pain. The U.S. National Library of Medicine and the National Institutes of Health, or NIH, states that PID is a general term that describes infection of the endometrium, or uterine lining; fallopian tubes; or ovaries. PID is usually caused by bacteria that migrate from the vagina into the other structures of the female reproductive tract. According to the NIH, the most common cause of PID is unprotected sex. Chlamydia and gonorrhea are two sexually transmitted diseases that can cause PID. Other ways in which bacteria can enter the body include childbirth, endometrial biopsy, insertion of an intrauterine device, miscarriage and abortion. Possible signs and symptoms associated with PID include the following: lower back, lower abdomen and pelvic pain and tenderness; fever; vaginal discharge; and fatigue.
Kidney Cancer
Kidney cancer can cause left-sided lower back pain. According to the National Cancer Institute, or NCI--a division of the National Institutes of Health--the kidneys are a pair of organs situated on either side of the spine in the abdominal cavity. The kidney is approximately the size of a fist. Kidney cancer most frequently manifests in people over the age of 40. Although the exact cause of kidney cancer is unknown, certain factors increase a person's risk for the disease, including smoking; obesity; hypertension, or elevated blood pressure; long-term kidney dialysis; exposure to certain workplace chemicals; and being male. The NCI states that males are almost twice as likely to develop kidney cancer than females. Common signs and symptoms associated with kidney cancer include the following: bloody urine, persistent pain in the side or lower back, a lump in the side or the abdomen, unexplained weight loss, fever and fatigue.
