DEAR DR. GOTT: In April 2010, I had partial shoulder replacement surgery. While in the hospital, I had an allergic reaction to one or more of the medications I was given. It started out with my head itching really badly and then spread to a rash on my back. At that time I was given Benadryl.

After I came home, it got worse and spread from my neck to my ankles. My knees and shoulders were covered in a solid red mass. It hurt to walk because my joints were stiff and painful. I went to my family doctor, and she diagnosed it as Stevens-Johnson syndrome (SJS). She told me that she had seen only one case worse than mine, and while I was in the doctor's office four different doctors came in to check out the reaction.

I have done some research on the Internet about this but really don't understand all of it. One doctor told me I would have the SJS for the rest of my life, and another told me that once the hives were gone I would no longer be bothered with it.

I also wonder if the SJS could have affected the healing of my shoulder. I am having a lot of pain and a burning feeling in my shoulder. My surgeon said that there is nothing he can do for me, and I should find out what medicine or medicines I am allergic to so I can take some pain medication.

I am totally confused and don't know what to do. If you could give me some information I would be grateful. Also, what tests can be done to determine what I am allergic to?

DEAR READER: Stevens-Johnson syndrome is a rare, yet serious condition in which the skin and mucous membranes adversely react to a medication, illness or infection. In some cases the cause cannot be identified. It can be a medical emergency that may require hospitalization. Recovery can take weeks or months depending on the severity.

Sore throat, burning eyes, fever and cough may begin several days before the skin manifestations. Hives, skin pain, facial and/or tongue swelling, sloughing (shedding) of the skin, blisters on the skin and mucous membranes (especially the eyes, nose and mouth), and a red or purple skin rash that spreads within hours or days may occur.

There are no standard recommendations for treatment other than immediately stopping whatever medication or offending agent causing the reaction. In many instances, physicians urge the discontinuation of all non-essential drugs. This is followed by supportive care such as eye care, wound care and replacing lost nutrients and fluids.

Antihistamines, pain relievers, antibiotics and topical or intravenous corticosteroids may also be prescribed. Intravenous immunoglobulin (IVIG) may be given in an attempt to stop the progression. Skin grafting may be required if large areas of the body area are affected by sloughing of the skin.

It is important to work with your physician to determine the cause. Because medication is often the cause, it is important to know which one caused the reaction. Become informed of other related medications that should be avoided. It is vital that all your physicians and caregivers be aware that you developed this reaction and what caused it. You should also wear a medical alert bracelet or necklace, so in the event of an accident where you are incapable of providing information to emergency personnel, they will be able to know at least part of your health history and thus avoid giving you the medication (or one of the related drugs) inadvertently.

Request that your primary care physician refer you to an allergist. He or she can examine and test you for allergies or sensitivities to various substances. This is especially important so that you can identify the culprit and avoid further contact or take preventive measures against it (such as in the case of infection).

You may also benefit from speaking with another orthopedic specialist or surgeon regarding your shoulder. Your healing may have been delayed as a result of the SJS, but to ensure nothing further is going on, examination and testing are your best bet.

Readers who are interested in learning more can order my Health Report "Allergies" by sending a self-addressed, stamped No. 10 envelope and a $2 U.S. check or money order for each report to Dr. Peter Gott, P.O. Box 433, Lakeville, CT 06039. Be sure to mention the title(s), or print an order form from my website's direct link: www.AskDrGottMD.com/order_form.pdf.

Dr. Peter H. Gott is a retired physician and the author of several books, including "Live Longer, Live Better," "Dr. Gott's No Flour, No Sugar Diet" and "Dr. Gott's No Flour, No Sugar Cookbook," which are available at most bookstores or online. His website is www.AskDrGottMD.com.