DEAR DOCTOR,

Is it normal for a scar of an almost 20-year-old injury to just start itching? I have a scar on my leg from a wound I got when I was much younger, but it itches like crazy and I wonder why. What could be the cause of this and how should I handle it?

PATRICK

DEAR PATRICK, 

What kind of injury did you have. Was it a clean wound or had it  become infected at that time? Is the skin over the wound normal or has it become thickened and rough?

Normally when a part of the body is injured,  the nerves supplying that part are also irritated and this manifests as itching. Also there is release of chemical mediators of inflammation in response, including histamine. This causes itchiness. During healing, the skin over the injury and adjoining part gets remodelled as new collagen and skin layer is formed over the injured part, stimulating the nerves beneath, resulting in itching.  Dryness over a healed wound whether  recent or old, also leads to itching. Old wounds formed due to burns or contractures are often itchy after healing, because the skin over and adjoining it becomes a bit tight during healing process.  

Keloid formation is one of the most common cause for an old wound to start itching. Keloids are like overgrown, raised  scars over an injury site. It happens due to overgrowth of the skin after healing and is due to tendency of the body in persons prone to it. A keloid often looks reddish or blackish. The skin overlying it , is often thickened and crab like and itches a lot. Though multiple factors are involved but, itching is a sure sign that the wound is healing well, or has healed well. If coincidentally fungus infection has occurred over the site of an old wound, it will manifest as intermittent severe itching and flaking of skin.

One should avoid scratching, in spite of the  temptation to do so, when it itches a lot. Because scratching by finger nails can lead to infection and abscess formation. This manifests as painful red swelling. As the abscess will heal after treatment, it can cause more itching. If at all necessary, a soft napkin or cloth should be used to wipe that area gently. Avoid tight fitting clothes or socks as they will irritate that part and aggravate the itching.  One should also avoid use of nylon clothes and socks, as they prevent aeration and augment itching. Applying  some lubrication like Vaseline or glycerine over the itchy part, helps in curing dryness of the skin, thus preventing itchiness.  In case of severe itching anti histamine drugs can be taken for a short duration for symptomatic relief. At times, steroid ointments applied for a short while also help in reducing itchiness. But they should be taken after seeking advice from a medic.

Dr Rachna Pande is a specialist in internal medicine 

E-mail: rachna212002@yahoo.co.uk