DEAR DR. DONOHUE: You have never written extensively on the current plague of the decade, AIDS. The small details are always left out in a discussion of this disease. Please go into more detail about it. It is possible that one of my family members might be infected. I have noticed small changes in the appearance of skin and hair. My family refuses to talk about it. – C.M.

ANSWER: AIDS, the acquired immunodeficiency syndrome, is not an illness with a single list of signs and symptoms. It’s a complicated condition in which the immune system is disarmed, and the signs and symptoms that appear depend on which infection the AIDS patient contracts or which cancer takes hold.

The general story goes like this: About one to six weeks after HIV – the human immunodeficiency virus, the virus that causes AIDS – enters the body, half to two-thirds of infected people come down with an illness that resembles mononucleosis. They develop a fever and sore throat. Lymph nodes enlarge. Muscles and joints hurt. The skin might break out in a measleslike rash. Many have diarrhea and complain of a headache. All these symptoms usually go away.

Then, for 10 or more years, there are no signs or symptoms. When they do emerge, lymph node enlargement is common. Infections that are easily warded off by those with a robust immune system take hold. The mouth might become covered with thick, white patches due to infection with the candida yeast. Purple spots can break out on the skin – Kaposi’s sarcoma, an unusual cancer. Fever and diarrhea are common. Infections of the brain, liver and eyes can spring up. Great amounts of weight are lost.

All of the foregoing has been revised since the onset of therapy that can hold the virus at bay for prolonged periods of time. It is given well before there are any detectable signs of illness, when the blood shows a dearth of CD4 cells – infection fighters – and when it shows a rise in the number of HIV viruses.

Many HIV-infected people are alive, active and working far past the prior 10-year limit. A casual inspection of hair and skin won’t disclose the illness, even to a practiced eye.

DEAR DR. DONOHUE: Recently you described melanoma as a dark-brown or black patch on the skin. My husband had a malignant melanoma on his scalp that was pale blue-gray. It was only sheer luck and divine intervention that caused me to notice it and insist on its removal. – C.C.

ANSWER: “Melan” is Greek for “black,” and most melanomas are dark-colored – brown to black. Your husband is an exception to the rule. In those exceptional instances, the diagnosis is made only after a biopsy of a skin patch that’s enlarging or one that has recently sprung up. Your observation and insistence saved your husband’s life.

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.