DEAR DR. DONOHUE: Please talk about lockjaw. I grew up on a farm, and it was something I heard about all the time. You were supposed to be careful when you were in a barn to spot any rusty nails you might step on. Is that so? I don’t hear much about it anymore. Why? – L.S.

ANSWER: I heard the rusty nail/lockjaw story as a kid too, and I didn’t grow up on a farm. Frankly it’s a seldom-seen illness since routine immunization against it has been in effect for many years. The real name of lockjaw is tetanus, and just about everyone has gotten a tetanus immunization.

The tetanus bacterium, Clostridium tetani, is found throughout the world in soil and in animal feces. A number of cases develop after a puncture wound when the bacterium is introduced deep into tissues. Rusty nails are only one way the germ gets into the body, and they are not the most common way.

The tetanus germ makes a poison that causes muscles to go into violent and painful spasms. Spasms of the jaw muscles are how tetanus came to be known as lockjaw. Patients can’t open their mouths. Tetanus also causes generalized muscle spasms, with the patient awake during the spasms. The slightest stimulation, a loud noise, for example, can trigger muscle spasms.

Penicillin, human tetanus immune globulin and medicines that control muscle spasms can get most patients through this harrowing illness.

I don’t want to scare people about tetanus. It is uncommon. However, everyone, at every age, should keep their tetanus immunizations up to date. They have to be obtained every 10 years. Only one-third of the adult population of the United States and Canada is adequately protected against tetanus.

DEAR DR. DONOHUE: Every spring I have hay fever so bad that I am virtually housebound. I have used antihistamines, nasal sprays, including steroid nasal sprays, cleansing my nose with saltwater flushes and many, many other medicines, but I do not get any relief. My primary care doctor suggests I see an allergist for allergy shots. Do they really work? Would you advise them? – H.M.

ANSWER: Allergy shots, also known as hyposensitization, work for most. An allergist first has to determine exactly what a patient is allergic to and then has a serum compounded that contains the allergic materials. The shots are then given in a series of weekly and in increasingly concentrated doses until a maintenance dose is reached, and that dose is then injected monthly.

The shots stop mast cells from emptying themselves of chemicals that spur allergy symptoms like sneezing, itching and running nose when allergic material lands on them.

I would advise anyone with severe allergy symptoms that do not respond to medicines to have allergy shots. You can start now and be prepared for the allergy season of spring when it arrives next year.

DEAR DR. DONOHUE: I have an adult son who has had a sore on the side of his nose for many months. I have pestered him to see a doctor, but he won’t. He says it stays there because he picks at it. Is that a suitable explanation? – W.M.

ANSWER: Any sore that doesn’t heal deserves a doctor’s examination. A nonhealing sore is a sign of skin cancer.

I’ve told the story of my grandfather many times. He had a sore on the side of his nose, and he neglected to take care of it. He put a salve on it that he got from a traveling salesman. The sore was a cancer, and he lost that side of his nose.

My other advice to your son is to stop picking the sore.

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.