I had shingles two years ago. So why am I STILL itchy now?

Q TWO years ago, I had a very bad attack of shingles in my right eye and scalp. I was in such agony I went to hospital and was put on a morphine drip for three days. My right eye and scalp now feel constantly irritated and itchy. I’ve been told there’s nothing I can do about it, but it drives me crazy. I’m 79 and otherwise fit and active.

Shiela Peczenik, Andover, Hants.

A What you describe is known as postherpetic neuralgia, a sensation triggered by nerve damage following shingles.

Shingles is caused by the varicella-zoster virus, the same virus that causes chickenpox. Like most of us, you probably have had chickenpox in childhood — after you recovered, the virus will have gone into hibernation in nerve tissue close to the brain or spinal cord.

Your immune system will have kept it under control for all that time until two years ago, when, for some reason, your immunity waned, allowing the virus to reactivate wherever it had been lurking for all those years. In your case, it was possibly in a branch of the trigeminal nerve, which is responsible for sensation in the forehead and eye region (the upper third of the face).

as well as the painful blistering rash of shingles, this will have caused an inflammatory response around your right eye and scalp.

the pain usually dissipates after several weeks, but in some people it can persist, and this is termed postherpetic neuralgia; essentially the nerve cells that were damaged by inflammation continue to send pain signals to the brain.

the damage may also cause areas of numbness and abnormal sensation when the skin is touched or something cold or warm is applied — in your case, this has triggered a persistent itching. there are drugs that can reduce the abnormal sensations, but treatment may have to continue for many months — with the occasional review by your doctor or a pain clinic specialist to fine-tune the correct dose. the two drugs of choice are gabapentin and pregabalin. these are anticonvulsant medicines which are also proven to be useful in the treatment of nerve-derived pain — they effectively dampen the pain signals.

the other option — with a similar mechanism — is taking a tricyclic antidepressant such as amitriptyline. this should be started at the dose of 10 mg taken at night (by comparison, as a treatment for depression the dose is much higher, 75mg to 150 mg).

Even at that low dose, sleepiness and dry mouth may be troublesome side-effects, particularly in the first week or two, and it may take up a month to notice any improvement.

One other suggestion to discuss with your GP is the prescription-only capsaicin cream, which contains a purified version of the ingredient in chilli peppers that makes them taste hot.

Research has shown this can help relieve nerve pain in the skin. It must be applied four times daily to the skin only (not the eye) and can cause a burning discomfort — which up to a third of users may find is worse than the symptom they are hoping to treat — but it might be worth a try. You have already suffered the complication for two years and I think there’s a strong case for talking to your GP about further treatment, or asking for a referral to a specialist pain clinic.

Q SINCE returning from a holiday four years ago, my feet have ached. At first I thought it was because I’d been wearing flip-flops, but I’ve had a number of different diagnoses and treatments.

After a second MRI scan, I’ve now been told it’s arthritis. I had steroid injections three weeks ago but, to my dismay, my feet are no better. I’m 84 and very healthy otherwise. My toes are fine — it’s my insteps and ankles that hurt.

Name and address supplied.

A I SENSE your frustration and disappointment — in your longer letter you detail a saga of different clinicians (including a podiatrist, two orthopaedic surgeons, and your GP), and now you feel that, despite treatment, the pain has not changed.

I note that the pain, under the instep of each foot as well as around the ankle, came on suddenly, and that you suspect it was triggered by wearing flip-flops.

It may be a cliche to blame walking in such unsupportive shoes, but it’s something I’ve seen several times, and on every occasion the diagnosis was plantar fasciitis.

this affects the soft tissues of the underside of the foot, specifically the ligaments that attach muscles of the underside of the foot to the underside of the heel bone. It’s caused by inflammation triggered by overuse (like a repetitive strain injury).

It may be that using your toes to grip on to the flip-flops to keep them on might have upset the usual muscle function of the underside of the foot — especially if doing more walking than usual when on holiday.

the condition is more common in older people, but affects both feet in only 10 per cent of cases.

the diagnosis is based upon the symptoms, with the pain often being most severe with the first steps of the day — and the point where the instep meets the heel bone feeling acutely tender when pressed.

Plantar fasciitis may not show up on scans, and these may even be misleading because if they reveal any arthritic change, this could be misdiagnosed as the cause of the pain.

the treatment includes rest, wearing supportive, wellcushioned shoes with good arch and heel support and, often, an orthotic in the shoe (a wedgeshaped one that raises the heel slightly). It usually takes six to 12 months to recover.

the question to ask your GP or orthopaedic specialist is whether your pain might be due to plantar fasciitis.