Q. I'm so allergic to perfume that I can't even go to a department store without suffering for days afterward. I feel like a hermit. I reacted to so many things on my allergy tests, even sterile water, that the doctor gave up for fear of making me worse. Will anything help? -- Yvonne, Florida

A. You probably have multiple chemical sensitivity (MCS) syndrome. Depending on whom you see for help, it may be treated as a genuine allergy, a psychogenic disorder (physical symptoms with a psychological cause), or a get-rich-quick opportunity by a charlatan who promises a pricey cure.

Why low-level, nontoxic exposure to certain substances can cause fatigue, weakness, dizziness, depression, headaches, joint pain or other MCS symptoms in you but not in your neighbor has long stumped immunology experts. Theories abound: That we've flooded the world with so many chemicals and scents that it's amazing more people aren't like you. That in some people, one chemical sensitivity evolves to many. That repeated exposure to irritants increases your reaction. That MCS is linked to depression and anxiety. Or that you're just highly sensitive to scents.

MCS may be a mystery, but you don't have to live like a hermit. (Though do learn to spot department-store perfume-spritzing terrorists from 50 paces.) Your best hope for relief is to seek the help of a holistic-minded doc who will consider all explanations for your condition, from chemicals to stress, and treat each symptom one by one.

Q. I have little white bumps on my upper arms. What causes them, and how do I get rid of them? -- Anonymous

A. Can you say "keratosis pilaris"? It's less embarrassing than "chicken skin," which is the street name for this common condition. It affects about 40 percent of adults and as many as 80 percent of adolescents (like they need another skin problem). It's caused when a protein in your skin forms hard plugs in hair follicles. The result can look like anything from permanent, rough, red and white goosebumps to a bad case of acne. As if that weren't annoying enough, sometimes it itches.

There's no cure, but this is one of those body oddities that gradually fades away as you grow older or will simply disappear on its own. Until that happens, you've got several options for minimizing the breakouts. Dryness makes it worse, so wash with a soapless cleanser (like Dove or Cetaphil), followed by moisturizer. For mild bumps, gentle exfoliation -- no harsh scrubbing, please -- can help loosen those plugs. For more serious cases, where the bumps are irritated and itchy, your doctor can prescribe lotions containing lactic acid, salicylic acid, alpha hydroxyl acid or retinoic acid, or a steroid cream.

Q. How much exercise is too much? Every day, I walk between 45 and 60 minutes and practice yoga. I swim and do core exercises three times a week. My doctor says I should slow down, but I hate to give up any workouts. Since I have been on the Mediterranean diet you docs recommend, I've lost weight and have 30 pounds and 2 inches from my waist left to lose. -- Frances, Florida

A. You don't say why your doctor wants to take the wind out of your sails. We're guessing it may be concern that you're not giving yourself time to recover between workouts and could burn out your brain or body. We don't think you have a problem, but here's why your doc might: something called "overtraining syndrome."

While overtraining syndrome mainly affects competitive athletes who constantly put the pedal to the metal, if you did cardio for two hours a day, you could be a candidate. When it happens, rather than getting stronger and better, you get weaker and worse. The reason: Your body needs downtime between workouts (especially strength training) to build new muscle fibers, sprout new capillaries to increase blood flow, replenish glycogen (your main fuel) and recharge your mitochondria (energy factories in your cells). You can't be constantly kicking butt for all of these to happen. You have to kick back, too.

If you're tired even after resting, feel blue, easily irritated, often muscle-sore or have frequent viral infections, you may be overtraining. Start giving yourself a day or two off a week. But if you feel good, we'd say start educating your doc: Buy him a copy of "The RealAge Workout: Maximum Health, Minimum Work" and tell him he probably should be doing a little more for his own maximum health.