DEAR DR. DONOHUE: Please discuss the management of seasonal allergies. Should I always take an antihistamine? Are some better than others? If I take one and two hours later I’m sneezing my head off, can I conclude that that one doesn’t work for me? Should I use eyedrops and nasal sprays along with an antihistamine? I notice my chin will start to itch before I have an attack. What do you make of that? — M.C.

ANSWER: If your allergies are really bad, you ought to consider immunotherapy, desensitization. Treatment has to begin before the allergy season sets in. An allergist tests you for suspected allergens (provokers), has a serum made incorporating those allergens and then begins the desensitization process. You start with a highly diluted shot of the allergen solution and gradually progress to stronger concentrations. You’re building a tolerance. Your need for medicines should be greatly reduce or eliminated.

If your allergies are not so bad, then you can rely on medicines. Start with an antihistamine. Which one is best for you is something you can determine only through trial and error. Allegra (a prescription medicine) and the nonprescription Zyrtec, Claritin and Tavist are popular choices. An effective antihistamine works until the next dose is scheduled, not for just two hours.

Rinsing your nose with a saltwater solution puts a stop to nasal symptoms. Dissolve half a teaspoon of salt and a pinch of baking soda in a cup of boiling water. Let the water cool. Gently flush each nostril with an irrigating syringe, found in all drugstores. Do this twice a day. If that doesn’t get the job done, then try nasal sprays such as Flonase or Nasonex.

If the antihistamine doesn’t stop eye itching, then you need eyedrops. I don’t know what to make of the itchy chin.

DEAR DR. DONOHUE: I am 72 years old, not married but still have sex. In October 2008, I went without sex until May 2009. My ejaculate had blood in it. My doctor said I must have an infection and put me on antibiotics. I saw a urologist, and he told me to continue with the pills. The next ejaculate had less blood. As time passed, there was no blood. I got it into my head that the blood happened because I wasn’t having sex. Is that true? — J.W.

ANSWER: Blood in the seminal fluid scares the man and his partner. It’s called hematospermia, and it’s relatively common. It can come from an infection, a tumor or an inflammation of the genital tract. Most often, it’s due to harmless breaking of tiny vessels in the place where sperm is stored. After a prolonged period of sexual abstinence, an obstruction often occurs in the sperm storage receptacle. Resumption of sex brings about bleeding that lasts only a few days. You were checked by two doctors. No serious cause was found. You can safely forget this episode.

DEAR DR. DONOHUE: I have a ruptured disc in my lower back. It took five shots to stop the pain. That was in 2006. My back hasn’t hurt since.

I was told not to wait too long to get the disc fixed because I might lose control of my bladder and bowels. What do you say are the odds of this happening? — J.W.

ANSWER: Back discs are oval affairs that lie between adjacent backbones. They absorb shock and keep the back limber. Each disc has a tough outer rim and a soft, jellylike core. When the outer rim develops even a tiny crack, the inner core protrudes through it. That’s a ruptured (or herniated or slipped) disc. If it presses on a spinal nerve, pain results. For 90 percent of people with this condition, the pain subsides in a month or so. Some have a ruptured disc but have no pain.

The protruding, jellylike core dries out. The problem goes away.

If pain persists, then a person can think about surgical correction. People without pain do not need surgery. The likelihood of your losing bowel or bladder control is close to zero.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.