Ask Dr Mark Porter

Our expert on diuretics, face pain and whether it’s OK to kiss your dog.

Q.  This may seem an odd question, but is it safe to let a dog lick your face? My sister has a Jack Russell which she adores. When he sits on her lap, she lets him lick her face, including her lips. It makes me feel queasy, but she says dog saliva is antibacterial, so I am worrying unnecessarily.

A. Saliva, both human and canine, does contain some chemicals which have antimicrobial or healing properties. But, having treated numerous infected dog bites over the years (and cat bites, which tend to be worse, infection wise), I wouldn’t let them lick a wound or graze as some people do. That said, our mouths are also packed full of bacteria – indeed we share around 50 different species with dogs – and human bites can pose a serious threat too.

In truth, problems normally only arise from bites where bacteria are pushed deep into the skin, and you are most unlikely to catch anything nasty from being licked by a healthy, regularly wormed dog – assuming you do not have a weakened immune system due to treatment like chemotherapy or any underlying illness.

I love dogs and have a seven-year-old Golden Retriever called Sid. However, if you saw what Sid gets up to… well, you wouldn’t want him ‘kissing’ you. And neither do I.

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Q.  Can you tell me the reason why I have to cut my fingernails every two weeks, but my toenails only every four to six weeks?

A. It is because fingernails typically grow twice as fast as toenails. American researchers monitored growth in a group of healthy young adults and found the average rate of nail growth in their hands was 3.5mm a month, compared to 1.6mm a month in their feet. The big toe has the fastest growing toenail, and the little finger has the slowest growing fingernail. Sound familiar?

It is unclear why there is such a variation between fingers and toes, but theories include trauma from using your hands more and differences in blood flow. Factors that slow growth include old age, poor nutrition and ill health, while being male and biting your fingernails speeds it up.

Q.  Can you help get to the bottom of a pain that my sister seems to be struggling to get help with. Whenever she eats or brushes her teeth, she gets a shooting sensation across the left side of her face. I have seen it happen over lunch and she winces and grabs her face, then it disappears as quickly as it arrived. Her dentist has found an infected nerve root on X-ray, but treatment hasn’t helped. Any ideas?

A.  I would have to examine your sister to be sure, but this sounds like trigeminal neuralgia (TN) – a severe, sporadic stabbing pain across one side of the face caused by compression of the trigeminal nerve (normally by nearby blood vessels).

It is most common in older people, and easily confused with dental or jaw problems, particularly if the pain is duller and more prolonged than normal (it can last minutes, rather than the classic ‘electric shock’ that lasts a few seconds). The fact that it is triggered by eating and brushing her teeth is typical, with other common precipitants including cold wind and touching your cheek. However, it can just strike out of the blue, too.

It often causes extreme distress and can be very debilitating. I would encourage your sister to see her GP and mention TN. Most cases can be controlled using medication (eg carbamazepine), but some require surgery to relieve the pressure. Please let me know the outcome.

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Q.  I am in my late seventies and have several health issues including diabetes, chronic kidney disease and mild heart failure, which leaves me breathless and means my ankles are constantly swollen. A heart specialist has suggested that I increase my water tablets (from furosemide 40mg a day to 80mg), but my GP is concerned about the impact on my kidneys – as am I. Is there a safer alternative?

A.  Furosemide is one of the most widely used and effective diuretics (water tablets) and a mainstay of treatment for heart failure where people tend to accumulate too much fluid – often in the ankles and legs, but elsewhere too, including the lungs where it can trigger marked breathlessness.

Many doctors are naturally wary of ‘flogging’ tired kidneys to remove more water (this is how furosemide shifts excess fluid – you pee it out). But used carefully, and monitored with blood tests, the drug is quite safe in people with kidney disease. Indeed, if it helps your heart failure it may actually improve your kidney function a bit.

It’s good to have a cautious doctor and the fewer drugs we all take, at the lowest dose that works, the better. But I would heed your cardiologist’s advice. Your GP will probably want to double check all is well by doing a kidney function test a few weeks after increasing the dose. I hope it helps with your fluid retention and breathing.

Q.  Can you gaze into your crystal ball please and tell us when the best time to book a holiday will be this year to avoid any restrictions? My wife and I are desperate to fly off somewhere warm and sunny and enjoy evenings eating outside again.

A.  You are asking the wrong chap. My wife Ros and I haven’t been on a plane for two years and the one trip we did book – to Greece last year – was postponed because of Covid. This pandemic has been full of surprises, not least the arrival of omicron, and I fear it has more up its sleeve. Late autumn and winter is always going to be the riskiest period, so I would be booking something between May and mid-November to have the best chance of a relaxing, ‘restriction lite’ break. This is what my family is doing this year. Good luck!

Email drmark@saga.co.uk. He can’t reply individually but will respond to queries in Saga Magazine. Always talk to your own GP.

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Article first published in Saga Magazine March 2022.