Your health questions answered

Have I been fobbed off with a made-up diagnosis? Can I rely on the result of a home pregnancy test?

WHY HAVE I GOT FACIAL PAIN?

Q. For many months I have been troubled by pains on the left side of my face and below my eye. Initially it was diagnosed as sinusitis, but it did not get better with several courses of antibiotics. I have had X-rays, an MRI scan and several bloods tests, all of which have come back as normal. After all this, I have been told that I have "atypical facial pain" and I have been put on a low dose of antidepressants. This is not because I am depressed - it is supposed to be treatment for the pain. I find the whole experience rather upsetting and confusing, and the pain seems no better. Is "atypical facial pain" a real illness, or am I being fobbed off?

A. A typical facial pain is a real diagnosis, but it tends to be a diagnosis that is made when everything else has been ruled out. No one really understands what causes this type of pain. It is sometimes called chronic oral and facial pain, or persistent idiopathic facial pain. All the long words mean the same thing - pain in and around the face for which no cause can be found. Sometimes the underlying cause lies in the temporomandibular joint, where the upper end of the jaw bone connects with the skull bone just in front of the ear. This joint can cause facial pain if it is slightly misaligned or if it becomes arthritic. Muscle tension around the face and jaw can also contribute to the pain, as can anxiety. It is also important to rule out dental problems as a cause of the pain. The use of antidepressants as a treatment for atypical facial pain is widespread and they do seem to work for some people. A low dose of an antidepressant is often effective in relieving the pain and breaking the cycle of pain and anxiety.

ARE TESTS ACCURATE?

Q. How accurate are home pregnancy tests? Is it possible to be pregnant even though the test is negative on the day my period is due? And is it possible that a positive pregnancy test could be wrong?

A. Home pregnancy tests are designed to detect tiny amounts of a hormone called human chorionic gonadotrophin (hCG) in the urine. The hormone is produced by the placenta, and it begins to appear in the mother's urine as soon as the developing embryo is implanted in the wall of the uterus - hCG cannot appear in the mother's urine until the embryo is attached to the uterus. The embryo attaches to the wall of the uterus between 6 and 12 days after ovulation. So if a woman has a 28 day menstrual cycle, she usually will ovulate on day 14 of her cycle. If she falls pregnant, the earliest time that hCG is present is about a week before her period is due. A small number of pregnancies will not have implanted by the first day of the missed period, and in these cases a urine pregnancy test will not yet be positive. A positive pregnancy test is extremely unlikely to be incorrect if you follow the instructions correctly. If you have had an injection of hCG (for fertility treatment) this could cause a test to be positive in a woman who is not pregnant.

WHAT'S CAUSING MY EYE TROUBLE?

Q. I have had three episodes of a painful eye over the past four years. Once it was the right eye, and twice it was the left. The first time it was diagnosed as conjunctivitis, but it didn't get better with antibiotic ointment. Eventually it became so painful that I went to the casualty department, where iritis was diagnosed. I was treated with steroid eye drops and it got better quite quickly. Since then it has come back twice for no apparent reason.

A. Iritis causes pain, redness and watering of the eye, together with light sensitivity and sometimes blurring of vision. It is not an infection of the eye (unlike conjunctivitis). In fact, it is an autoimmune condition, in which the body produces a reaction against itself. A person who is developing iritis usually feels that the eye is a bit sore and red at first. This quickly progresses to quite a painful eye. The redness in iritis is concentrated around the iris. This is unlike conjunctivitis, in which the redness tends to be worst near the eyelids. As the inflammation of the iris becomes worse, the pupil can become small and irregularly shaped. People who get iritis sometimes have another underlying condition, such as ankylosing spondilitis, or inflammatory bowel disease. But about half of the people who get iritis get it for no apparent reason. The best way to treat it is with steroid eye drops, and drops to make the pupil open up. You are unlucky that the iritis has come back twice, as it often clears up, never to return.

Readers write

Two more suggestions for easing hip pain at night:

From LA: “You suggested that hip pain was unlikely to be arthritic if there was no pain walking. I had the same problem and was finally referred to an orthopaedic surgeon when a physio suggested I may have an arthritic hip. I only had pain when I was lying in bed. X-rays showed a severely arthritic hip which has been treated extremely successfully by the Birmingham hip operation.”

And from JB: “I have bursitis and exactly the problems mentioned by your correspondent. I have found using a 2in thick foam ‘mattress topper’ very helpful. This reduces pressure on the sore area. The one I use was not the most expensive, but works well.”

Please send your questions and suggestions to A Question of Health, The Independent, Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182; or e-mail health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally to questions.