DEAR DR. DONOHUE: About two months ago, I wrote you inquiring about the shingles vaccine for polio victims. Will the vaccine cause the polio virus to reactivate, or will it cause a severe case of shingles? — N.J.

ANSWER: People born after the polio vaccine became available in 1955 have little appreciation of what a dreaded illness it was. Polio is coming close to being eradicated worldwide. That goal hasn’t been achieved, but it appears to be doable.

Many people who suffered from the paralysis caused by polio are now faced with another problem — post-polio syndrome. The muscle strength they regained after the initial infection is being lost, and pain is re-emerging. That’s not because the polio virus has come back to life; it’s because nerves that took over for nerves killed by the virus are now degenerating.

I referred your question to Post-Polio Health International, an organization that should be known to all victims of polio and all those suffering from post-polio syndrome. They have had experience fielding such questions. Their medical experts see no reason not to take the shingles vaccine. It does not reactivate the polio virus. Nor does it cause post-polio patients to have a severe case of shingles.

Post-polio patients ought to contact Post-Polio International and learn about its many services available to previous victims of polio. Its website is www.post-polio.org.

DEAR DR. DONOHUE: Regarding applying lotion to the back, there is a long-handled applicator with three round lotion containers. Then about 20 balls apply the lotion as you roll it up and down your back. It is priced below $10.

I have seen it at Bed, Bath and Beyond and at Walgreen’s. — G.V.

ANSWER: Thanks for the information. Both the letter writer and I could use such a gadget. I haven’t checked out either place yet, but I intend to.

DEAR DR. DONOHUE: Please explain the disease porphyria. We recently lost a young man, age 44, from this illness. One of its signs was hypopigmentation of the skin. Is it genetic? Is there a cure? — N.J.

ANSWER: Porphyria is not an easily explained illness. It’s not one illness. It’s eight illnesses. Furthermore, it involves eight different enzymes. Enzymes are body proteins that speed cell chemistry. In this case, it’s chemistry involving production of heme, the large material inside every red blood cell that transports oxygen from the lungs to the rest of the body.

The production of heme involves eight steps, with an enzyme required at each step. Each of the eight porphyrias has a distinctive enzyme missing for one of the eight steps. The missing enzyme leads to an accumulation of only partially formed heme precursors that cause either skin or nerve trouble.

One of the consequences of the most prevalent variety of porphyria — porphyria cutanea tarda, PCT — is severe and painful blistering of skin. Sunlight triggers the reaction.

I can’t describe the unique manifestations of all eight diseases. Most of them are inherited. There may not be cures for all, but treatments are available for most.

The best I can do for you and those suffering from porphyria is to refer you to the American Porphyria Foundation (www.prophyriafoundation.com) or the Canadian Porphyria Foundation (www.cpf-inc.ca) for detailed information on this family of illnesses. If affected people are not aware of these foundations, they should contact them. They will have found a friend they didn’t know they had.

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.