Clear passage

Allergic conditions are the most common problem treated by ENT surgeons here. TAN SU YEN reports on their treatment and new methods to trace the cause of allergies

THERE are those who wake up and smell the coffee, and then there are those of us who wake up to a sneezing fit so dramatic we can barely smell a thing. And it isn't just the sneezing. There are the itchy, streaming eyes, the equally itchy, runny nose and the endless routine of nose-blowing, sniffing and snivelling to contend with. It hardly adds up to a pretty picture but that's allergic rhinitis for you.

One in four Singaporeans is believed to suffer from allergic conditions, of which the most common is allergic rhinitis. The good news is that allergic rhinitis is eminently treatable even if there is no 'cure' for it as such, says consultant ear, nose, throat surgeon Dr Ravi Seshadri, who is clinical director of MD Specialist Healthcare, a member of Pacific Healthcare.

'You don't expect a cure for your allergies because it is in your genes, so you try to control and manage the problem. Our role is to try to bring the nose back to the point where patients are happy with it and then teach them how to maintain the nose themselves,' he says

To help patients achieve some clarity on their condition, Dr Ravi typically shares this analogy: 'This is what I tell all my patients with allergic rhinitis: just consider yourself to have asthma but you don't have asthma in the lungs, you have asthma in the nose. We want you to try and control and prevent this asthma in the nose. Don't look for a cure because there is no cure for asthma so it really is up to you to look after yourself.'

Dr Ravi estimates that 80 to 90 per cent of all cases of allergic rhinitis can be treated successfully with medication and surgery may not be required. In children, treatment with medication is the norm. 'Quite often patients have to take antihistamines. In the past antihistamines were sedating. However, now we have the non-sedating type which allows people to carry on with their normal routine of work or studies when they are on medication.'

In recent years, topical nasal steroid sprays have emerged as a safe and effective way of managing allergic rhinitis although some patients remain apprehensive about being prescribed steroids. Says Dr Ravi: 'When you tell the patients that there is a topical nasal steroid spray they get a bit worried but the steroid sprays we have now are very good. They treat the nose but they don't get absorbed into the blood stream and affect the body so you don't have to worry about side-effects.'

Patients typically stay on their medication for two to three months before stepping down to medicating on a need-to basis. 'Once the patients are well, I generally tell them to tail down the medication themselves and to take it minimally as needed.'

The good doctor also prescribes exercise as a healthy and active way to manage allergies. 'I encourage all my patients to start exercising regularly because when you exercise, your immunity builds up and as your immunity goes up, your allergy goes down.'
But not all patients are in a position to go off their medication after three months even if their condition has improved, Dr Ravi reveals. 'If patients are allergic to certain things in their environment that they can change, they have to do it. Occasionally, you come across some patients who are allergic to pets, like cats and dogs, and they want to keep their pets. If you want to have your pet, then you should be ok with taking the medication if you want to control the symptoms. Ultimately it is a lifestyle situation and a lifestyle decision that the patient has to make.'

That lifestyle choice is possible only because allergic rhinitis has no sinister undertones whatsoever. 'The difference between allergic rhinitis or what I call 'asthma in the nose' and asthma in the lungs is that when your nose gets blocked or runs or you sneeze it is frustrating but it is not going to kill you. However, with asthma in the lungs if you don't look after yourself it could kill you.

'When you have asthma in the lungs and you have an allergy to pets, then you have to seriously think: 'Am I going to have a pet or not?' When you have allergic rhinitis then most people don't mind having a blocked nose, but they want to keep their pets.' Having said that, Dr Ravi points out that sinusitis, a condition that often gets confused with allergic rhinitis, requires more immediate attention. 'Going back to the analogy of having asthma in the nose - if you have sinusitis together with the allergic rhinitis it is like having a bronchitis infection with your asthma. So you have to treat the infection first before you manage the asthma.'

The sinuses are air-filled cavities within the facial bone. If the nose is badly congested with mucus or fluid because of allergic rhinitis, air cannot get into the sinus cavity to ventilate it. As a result, the drainage of the mucus into the nose is hampered; the mucus becomes stuck within the sinuses and gets infected, filling up with pus.

Chronic cases of sinusitis may require surgery to surgically drain the pus or clear the diseased sinuses. If the patient is seen early the infection could be treated with medication. While much of the emphasis in most ENT practices is on the nose, Dr Ravi, who is a visiting consultant at the voice clinic at Tan Tock Seng Hospital, also sees patients with voice problems at his private practice. Patients seen frequently are those who work with their voices like teachers, singers and radio and TV professionals.

Says Dr Ravi: 'Most of the time, they have used their voices for too long and with too great an intensity. They may also be using the wrong technique to project their voices and they don't hydrate their vocal cords enough.'

Hoarseness as a result of straining your vocal cords can lead to cysts or polyps forming in the voice box. These growths can be examined using a probe known as a laryngeal stroboscope. Treatment for voice problems usually takes the form of voice therapy and medication, accompanied where necessary, by surgery.

In Dr Ravi's book, however, prevention is still the best strategy for those who use their voices daily on the job. 'I would urge school teachers, for example, to use a microphone and to keep a bottle of water by their side and take sips from it every 15-20 minutes to rehydrate themselves,' he says.

Getting to the root of that chronic cough

A COUGH that simply won't go away can be very trying - both for the victim and for people around the sufferer. Imagine being in full flight at a presentation only to be overcome by a wave of coughing, or inadvertently adding some unwelcome accompaniment to a virtuoso concert performance with a hacking cough.

Physicians classify a cough that lasts for longer than three weeks as persistent enough to warrant further investigation. If the cause is believed to lie in the lower respiratory system, a patient will be referred to a respiratory physician. If the seat of the problem is believed to lie further up, the patient should see an ENT specialist.

Long-lasting coughs due to upper respiratory causes are more common than people realise, says consultant ENT surgeon Dr Gerard Chee Hsien of G H Chee Ear Nose Throat & Dizziness Centre, a member of Pacific Healthcare. 'There are a few broad causes that are related to a chronic upper respiratory cough - allergies, oesophageal reflux, infections like viral laryngitis or a bacterial infection, or even an infection from another part of the respiratory system that affects the throat, like sinusitis.' Dr Chee's special area of interest within ENT lies in chronic cough induced by allergies and sinusitis. Such coughs can affect both children and adults. In fact, 25 per cent of the general population in Singapore is believed to suffer from some form of allergy.

Allergies can be divided into those caused by inhalants or what you breathe and those caused by food or what you eat. Dr Chee says: 'Dust mites are the most common cause of inhalant allergies in Singapore, although what people are allergic to are not the dust mites themselves but the microscopic faeces of the dust mites. Dust mite allergies account for 80 per cent of all inhalant allergies; the other 20 per cent is made up of allergens like cockroach faeces, grasses, pollens, cats and dogs dander and just about anything that can float in air. We can test for the common allergens but it is impractical to test for all possible aeroallergens.

'The other more controversial area of allergies is food allergies. Within food allergies there are histamine-related food allergies and there are non-histamine related food allergies. Most specialists managing allergies such as immunologists and paediatricians understand and accept histamine related food allergies like seafood, chocolates, peanuts and eggs, all of which are foods that can potentially release histamine. Non-histamine related food allergies are more controversial and difficult to diagnose and manage.

'I believe that you can be allergic to just about anything that you eat; it doesn't have to be histamine related. Many researchers are trying to unravel the pathogenesis of this kind of food allergy. 'Allergic conditions like allergic rhinitis cause a cough through a process that doctors describe as a postnasal drip, in which mucus is discharged from the nose into the throat causing irritation in the process. The same thing happens with sinusitis, but with sinusitis it is pus which pours backwards into the throat. Managing the sinusitis, with medication and where necessary endoscopic sinus surgery, usually addresses the cough. Similarly, antihistamines address the postnasal drip caused by histamine related allergies. The missing link is how to treat patients with non-histamine related food allergies.'

Dr Chee says: 'There are children who have been tested to have histamine related food allergies and who are on antihistamines but who continue to suffer from symptoms like chronic cough, runny nose, blocked nose and sneezing. This tells us that there is something else that is causing the allergy other than histamine release. Otherwise their symptoms would have been controlled with antihistamines.'

While the standard skin-prick test is used to ascertain histamine related allergies, Dr Chee and clinicians at the National University Hospital (NUH) use a different technique known as the Intradermal Provocation Food Test (IPFT) to determine non-histamine related food allergies.

Dr Chee says: 'This can be quite a painful test in which food extracts are injected directly into the patient's dermis. In order to determine what food extracts to test, we ask patients to keep a food diary for two weeks and we test for the 15 to 20 foods that the patients eat most frequently. Most adults will be able to tolerate the test, which is done in a clinic and takes about 90 minutes to perform. With children, we generally do the test under sedation and take the opportunity to clean out their noses at the same time.'

On average, the tests reveal three to five types of food that the patient may be allergic to, although Dr Chee has seen patients with more than 10 food allergies. The challenge then is for the patient or the parents of the young patient to come up with a diet that excludes these offending foods. Dr Chee says: 'The good news is that we do not need to omit these foods forever. The recommended period for dietary control is six months, preferably one year. After that, we can introduce these foods in small amounts into the diet. The immune system goes through a process of modulation during the period when the offending foods are eliminated and it doesn't react to these foods when they are reintroduced after laying off for a period of time.'

Source: Business Times,25 August 2006