Ab strain or hernia?
Bear down as if you're having a bowel movement, and feel the area in question. "A lot of times you can feel a soft protrusion where intestines have poked through the abdominal muscles," says Travis Stork, M.D., MH's emergency-medicine advisor and the author of The Lean Belly Prescription. That's a hernia.
If your abs are strained, lay off exercise for a few days and they should recover. But if the area suddenly becomes more painful, particularly after you cough or lift something heavy, you could have a strangulated hernia. That's a medical emergency; see a doctor.
Sensitive tooth, or a cavity?
Examine the tooth in a mirror. If it appears shinier than the teeth near it (or if its gum line has receded more), you may have worn away the enamel or gum by overbrushing, says Denis Kinane, B.D.S., Ph.D., of the University of Pennsylvania school of dental medicine. But if the tooth has a cavity, it may still look just like the neighboring teeth.
See a dentist if you suspect a cavity. If you have sensitivity, don't worry: It's common and may improve with time. (Consider a toothpaste like Sensodyne. And don't overbrush.) A dentist can verify the diagnosis at your next visit.
Fracture, or sprain?
Use the tip of your finger to press where it hurts, and then press the surrounding area. "If you put pressure on the bone and it doesn't hurt as much as, say, the area next to it, it's probably a sprain," says Jonathan P. Garino, M.D., an orthopedic surgeon based in suburban Philadelphia. But if touching the bone itself causes more pain, it's likely a fracture.
Monitor your pain. Due to inflammation, a sprain will be worse the day after the injury. If you suspect a fracture or it doesn't improve within 48 hours, see a doctor as soon as possible.
Jock itch, or herpes?
Scratch the inflamed area. If skin flakes off, or if the area becomes warmer and itchier after a sweaty workout, you probably have jock itch, says Adnan Nasir, M.D., MH's dermatology advisor. Jock itch also worsens over time. By contrast, a herpes outbreak looks like a cluster of red bumps capped with clear blisters. Plus, the area will clear up between outbreaks.
Jock itch typically stays in the folds of your skin and can be treated with an over-the-counter cream such as Lamisil. Herpes can spread around any area of your genitals, and while medication can prevent outbreaks, there is no cure. See your doctor and talk to your partner. That being said, you can have herpes even if you don't have the telltale bumps. In fact, even though 16 percent of people in the United States have the virus, only one quarter of them know they have it.
Toenail fungus, or runner's toe?
Trim the affected nails. "With toenail fungus, the nail is frail and crumbles like chalk when trimmed," says Dr. Nasir. "The nail also lifts easier, leaving a gap between the nail and the nail bed, unlike with runner's toe." The final test: Give it a sniff. Fungus stinks; runner's toe doesn't.
Toenail fungus goes away after treatment. If you have a case of runner's toe, you can prevent it from returning by wearing narrower shoes. "The less space in the sneaker," Dr. Nasir says, "the less your foot will slide and jam into the wall of the shoe."
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