Dear Dr. Donohue — I have a rash that has lasted for six months.It’s very itchy. The itchy spots are both large and small. I getthem all over my body at different times. I have been on Zyrtec forthree months, but it only controls so much. I also take Benadryl. Ihave been diagnosed with peanut allergy.How long does it take forpeanuts to leave the system? — J.S.
Answer — You describe chronic hives (urticaria) to a T. It’srecurrent outbreaks of itchy, red skin bumps that look a bit likemosquito bites. Chronic hives are crops of them that keep appearingfor longer than six weeks. although everyone immediately thinksthis is an allergic reaction, allergy is the cause in only a fewpeople. The mechanisms causing the outbreak are understood, butwhat turns those mechanisms on isn’t understood. Histamine and ahost of similar body chemicals are released into the blood. Moderntheory suggests that the release stems from an attack by the immunesystem on cells that produce those chemicals.
Many doctors check for food and drug allergies. Foods that areimplicated the most are spices, herbs, eggs, seafood, smoked meats,tomatoes, peas, mushrooms, spinach, olives, breads and margarines.The most often blamed drugs include penicillin, sulfa, diuretics(water pills), aspirin, NSAIDs (Aleve, Advil, etc.) and ACEinhibitors (blood pressure medicines). Thyroid disease sometimesbrings on hives. although these things are not commonly found ascauses of chronic urticaria, a search for them can be a huge helpto the minority of cases in which they are playing a role.
Treatment centers on antihistamines taken on a regular basis,not just when an outbreak occurs. Zyrtec (cetirizine) is oftenchosen. Allegra, Claritin and Clarinex are other frequent choices.Benadryl and Atarax, two older antihistamines, are most useful whentaken before bedtime.
They’re sedating and can provide uninterrupted sleep. on thebright side, most people get over chronic hives in one to twoyears. on the dark side is the fact that not all do.
Dear Dr. Donohue — I saw an article about a new kind of AIDSvirus, called AIDS-2. it was alarming. it said this new virus couldspread even more widely than the older virus. is this just anotherexample of fear-mongering? — T.R.
Answer — HIV-1, human immunodeficiency virus 1, is the majorcause of AIDS. HIV-2 is a virus similar to HIV-1 that causes AIDS,usually to a lesser degree than does the HIV-1 virus. HIV-2 appearsto have originated in the west coast of Africa. It’s not a newvirus. It’s been known for many years. It’s treated with the samemedicines used for HIV-1.
Write Dr. Donohue at P.O. Box 536475, Orlando, Fla.32853-6475.