Retired GP, journalist and author James Lefanu has written a column for The Telegraph for 20 years. He always welcomes letters from readers about any of their medical concerns

Recently I received a letter from a reader in Somerset in his mid seventies. He described himself as “fit as a fiddle” thanks to yoga breathing exercises every morning and daily walks with his labrador on the Mendip Hills. Nonetheless he explained that he has been “driven mad with desperation” by chronic itchiness of his skin and scalp. “There is nothing to show for it” he writes, “no rashes only my scratch marks”. The likely culprit, given his age, is the rather cruelly named senile itchiness (or pruritus) caused by age-related thinning and dryness of the skin. The generous application of the moisturisers and emollients prescribed by his family doctor has, however, provided only scant relief. So what to do?

This is not straightforward as there is a longish list of possible explanations warranting. In their most recent report, The British Association of Dermatologists advises an extensive range of investigations of liver, kidney and thyroid function. While there are many possible causes, two possibilities in particular need to be pursued. The first, for reasons that remain obscure, is iron deficiency. This should be readily established by the standard blood test but is not excluded by a normal result and more specialised measurements may be necessary. Iron supplements are almost immediately (and dramatically) effective. Next, severe itchiness, especially at night, may be the only sign of Hodgkin’s lymphoma so a CT scan of the chest and abdomen “should be considered”.

Despite the most thorough of investigations, for most no underlying cause can be identified. This is Generalised Pruritus of Unknown Origin (GPUO) that may be alleviated by the same drugs – antidepressants and Gabapentin – that are of value for the relief of neuropathic pain.

Partial knee replacements may be the answer

Further to the recent comments on why “tried and tested” types of knee implants might be preferable to innovative newer models, I am grateful to orthopaedic surgeon William Tice for drawing attention to the relative merits of the two main operative procedures – the total and partial knee replacement.

The former, as its name indicates, entails removing the arthritic damaged cartilage from the ends of both the upper and lower bones of the knee joint (the femur and tibia respectively) and replacing them with a metal and plastic implant. The “partial”, by contrast, is suitable for those in whom the arthritic changes are limited to the inner or outer aspect (or compartment) of the knee. This is replaced in the same manner leaving intact the unaffected side.

The partial is appropriate for around half of those requiring a knee replacement and, being a less extensive procedure, recovery is speedier with reduced likelihood of complications such as thrombosis and infection. It is, however, technically more difficult, so many surgeons, Mr Tice observes, stick to doing the total which accounts for the vast majority (86 per cent) of knee replacements in Britain. In practical terms this makes little difference as both procedures have a similar high success rate. Nonetheless, as these figures suggest, around a third of those having the ‘total’ will have done as well (or better) with the’ partial’. Useful to know.

Why tight clothes could be causing havoc with your health

A century or more ago, doctors attributed a host of digestive and respiratory ills in women to the “injurious effect of having to wear tight corsets”. The modern equivalent is reported by a lady from Woking intermittently troubled by stomach pains and loose stools but only when at work. It then occurred that whereas she wore a girdle during the week, she dispensed with it when at home at the weekend. “Though quite slim” she comments “like a lot of women past menopause, I have a largish stomach”. She put aside her girdle and has not been troubled since. This is almost certainly the female variation of “tight trouser syndrome” experienced by men whose symptoms of abdominal