Q. I am a 61-year-old man. In the past few months, I have been troubled by sudden daily eruptions of rashes. I usually feel the itch in the evening.
If I scratch at the area, rashes, which look like boils, will appear. Sometimes, the rashes disappear by midnight. I have tried using calamine lotion and balms, but to no effect. I am told that these rashes could be due to age-related hormonal imbalance. Is there any truth in this? How can I get rid of them?
A. Your clinical history suggests that you have chronic hives (also known as urticaria).
Chronic hives usually present as batches of red or white itchy wheals, patches or rings that can vary in shape and size, with surrounding skin becoming red (flare). They can occur on any part of the body.
Each individual rash can last from several minutes to a few hours but, in general, it tends to resolve within a day, as in your case. However, as some rashes disappear, new rashes may develop. It can then seem as if the rash is moving around the body. The rash may clear completely, only to return a few hours or days later.
Fortunately, the rashes tend to resolve without any scarring unless the skin has been injured while scratching to alleviate the itch.
While most cases of hives go away within a few weeks, for some, they are a long-term problem. Chronic hives are defined as hives which last more than six weeks, or hives that go away but often recur. A trigger causes the release of chemicals (for instance, histamine) from special cells (mast cells) in the skin.
These chemicals cause the tiny blood vessels under the skin's surface to become leaky. The pooling of leaked fluid in the skin causes a wheal. They can also cause the blood vessels to dilate, resulting in greater blood flow to the skin, causing the redness around the wheals.
Unfortunately, for most cases of chronic hives, a cause is never clearly identified. In some cases, chronic hives may be related to an underlying autoimmune disorder, such as thyroid disease or lupus. For some people, the rash can be triggered by heat, cold, pressure, scratch (trauma), emotions, exercise or sunlight, a condition called physical urticaria. You may have an overlap of physical urticaria, as scratching and changes in temperature (cooler temperatures in the evening) seem to trigger your rashes.
It is rare for chronic hives to be caused by an allergy to food or medication. However, a rare variant called urticaria vasculitis can occur in a small number of cases.
In this condition, the wheals last for more than 24 hours. They are often painful, may become dark red, and may leave a red mark on the skin when they disappear.
You may want to see your doctor or dermatologist to confirm if your rash is due to chronic urticaria. Treatment usually involves treating underlying medical conditions, avoiding identifiable triggers and symptom relief with oral medication such as antihistamines. In severe cases, immune suppressive agents can be given.
In your case, as the creams you have used do not work, you may need oral medication to provide you with the necessary relief.
DR RAYMOND KWAH
Dermatologist at Dermatology & Surgery Clinic at Paragon Medical Centre and Equity Plaza