Dr Bernadette Carr answers your question on cold sores and cystitis

I never had a cold sore until two weeks ago — it has now cleared up, is there anyway to prevent another one?

Cold sores can be very tender and painful. At the primary stage, it is asymptomatic but may reactivate later in life.

They usually resolve without any treatment but this can take seven to 10 days and begin with an itch or tingling, this can last from several hours or up to a day.

Cold sores appear as groups of small blisters on the lip and around the mouth and are caused by the herpes simplex virus (HSV). The incubation period is one to 26 days.

Once you have had a cold sore, the virus settles in to a nearby nerve sheath and stays there for the rest of your life.

For the majority of the time, it is inactive and causes no symptoms. It becomes active from time to time in some people, causing cold sore blisters around the mouth with a variable recurrence rate and may be associated with chest infections, emotional stress, menstruation and exposure to sun.

Antiviral creams are available and these may help to reduce the severity of the symptoms if they are applied when the itch or tingling begins. It is not possible to completely prevent sores but here are some suggestions to prevent the sores spreading:

* Make sure you do not to touch the cold sores — only touch them when applying antiviral creams and wash hands thoroughly with soap and water afterwards.

* Avoid sharing cups or lip balms.

* If using antiviral cream, dab it on the sore, rather than rub it in, to prevent damage to the blisters or cause more pain.

* Using a sun block on your lips may help to prevent cold sores triggered by exposure to sunshine.

When our bodies are placed under stress or our immune system is low, the likelihood of a cold sore flare up is more likely to occur. Try to relax and include some form of relaxation in your daily routine, ensure you get a good night’s sleep.

If you develop another cold sore I would suggest making an appointment with your GP who can advise you as to how to manage any future outbreaks.

I am a woman in my 30s and recently had cystitis, is it possible to prevent getting another infection?

Cystitis can be very uncomfortable and I can understand why you want to avoid a recurrence. Most bladder infections, including cystitis, are common in women and they will usually clear without any complications in a few days.

Cystitis means a burning discomfort on passing urine as a result of inflammation of the bladder. The usual treatment is with a course of antibiotics if bladder infection is diagnosed and paracetamol or ibuprofen will help to ease the pain. Symptoms of bladder infection include:

* Frequent and painful urination.

* Abdominal pain.

* Blood in the urine.

* Generally feeling unwell.

* Temperature.

Urine infections are caused by bacteria that come from the bowel and travel through the urethra to the bladder and into the urine. These germs do no harm in the bowel but they can cause infection if they get into other parts of the body.

As the urethra is shorter in women than in men, women are eight times more likely to develop cystitis than men and about half of women will have at least one episode of cystitis in their life.

Given that cystitis may be caused by an infection, it is not possible to completely prevent it but here are some general suggestions:

* Avoid using perfumed bubble bath, soap or shower gel and shower rather than bath.

* Always empty your bladder fully when you go to the toilet.

* When you go to the toilet always wipe yourself from front to back to prevent germs travelling up through the anus.

* Never delay going to the toilet as it can make you more vulnerable to infection.

* Wear underwear made from cotton rather than synthetic material.

* Avoid wearing tight fitting jeans and trousers.

* Drink plenty of fluids.