Allergies happen when your immune system overreacts to a normally harmless substance like dust or pollen. Hay fever, hives and anaphylaxis are all types of allergic reactions.

Many of those affected reach quickly for antihistamines to treat mild to moderate allergies (though adrenaline, not antihistamines, should always be used to treat anaphylaxis).

If you’re using oral antihistamines very often, you might have wondered if it’s OK to keep relying on antihistamines to control symptoms of allergies. The good news is there’s no research evidence to suggest regular, long-term use of modern antihistamines is a problem.

But while they’re good at targeting the early symptoms of a mild to moderate allergic reaction (sneezing, for example), oral antihistamines aren’t as effective as steroid nose sprays for managing hay fever. This is because nasal steroid sprays target the underlying inflammation of hay fever, not just the symptoms.

Here are the top six antihistamines myths – busted.

Myth 1. Oral antihistamines are the best way to control hay fever symptoms

Wrong. In fact, the recommended first line medical treatment for most patients with moderate to severe hay fever is intranasal steroids. This might include steroid nose sprays (ask your doctor or pharmacist if you’d like to know more).

Studies have shown intranasal steroids relieve hay fever symptoms better than antihistamine tablets or syrups.

To be effective, nasal steroids need to be used regularly, and importantly, with the correct technique.

In Australia, you can buy intranasal steroids without a doctor’s script at your pharmacy. They work well to relieve a blocked nose and itchy, watery eyes, as well as improve chronic nasal blockage (however, antihistamine tablets or syrups do not improve chronic nasal blockage).

Some newer nose sprays contain both steroids and antihistamines. These can provide more rapid and comprehensive relief from hay fever symptoms than just oral antihistamines or intranasal steroids alone. But patients need to keep using them regularly for between two and four weeks to yield the maximum effect.

For people with seasonal allergic rhinitis (hayfever), it may be best to start using intranasal steroids a few weeks before the pollen season in your regions hits. Taking an antihistamine tablet as well can help.

Antihistamine eye drops work better than oral antihistamines to relieve acutely itchy eyes (allergic conjunctivitis).

Myth 2. My body will ‘get used to’ antihistamines

Some believe this myth so strongly they may switch antihistamines. But there’s no scientific reason to swap antihistamines if the one you’re using is working for you. Studies show antihistamines continue to work even after six months of sustained use.

Myth 3. Long-term antihistamine use is dangerous

There are two main types of antihistamines – first-generation and second-generation.

First-generation antihistamines, such as chlorphenamine or promethazine, are short-acting. Side effects include drowsiness, dry mouth and blurred vision. You shouldn’t drive or operate machinery if you are taking them, or mix them with alcohol or other medications.

Most doctors no longer recommend first-generation antihistamines. The risks outweigh the benefits.

The newer second-generation antihistamines, such as cetirizine, fexofenadine, or loratadine, have been extensively studied in clinical trials. They are generally non-sedating and have very few side effects. Interactions with other medications appear to be uncommon and they don’t interact badly with alcohol. They are longer acting, so can be taken once a day.

Although rare, some side effects (such as photosensitivity or stomach upset) can happen. At higher doses, cetirizine can make some people feel drowsy. However, research conducted over a period of six months showed taking second-generation antihistamines is safe and effective. Talk to your doctor or pharmacist if you’re concerned.

Myth 4. Antihistamines aren’t safe for children or pregnant people

As long as it’s the second-generation antihistamine, it’s fine. You can buy child versions of second-generation antihistamines as syrups for kids under 12.

Though still used, some studies have shown certain first-generation antihistamines can impair childrens’ ability to learn and retain information.

Studies on second-generation antihistamines for children have found them to be safer and better than the first-generation drugs. They may even improve academic performance (perhaps by allowing kids who would otherwise be distracted by their allergy symptoms to focus). There’s no good evidence they stop working in children, even after long-term use.

For all these reasons, doctors say it’s better for children to use second-generation than first-generation antihistimines.

What about using antihistimines while you’re pregnant? One meta analysis of combined study data including over 200,000 women found no increase in fetal abnormalities.

Many doctors recommend the second-generation antihistamines loratadine or cetirizine for pregnant people. They have not been associated with any adverse pregnancy outcomes. Both can be used during breastfeeding, too.

Myth 5. It is unsafe to use higher than the recommended dose of antihistamines

Higher than standard doses of antihistamines can be safely used over extended periods of time for adults, if required.

But speak to your doctor first. These higher doses are generally recommended for a skin condition called chronic urticaria (a kind of chronic hives).

Myth 6. You can use antihistamines instead of adrenaline for anaphylaxis

No. Adrenaline (delivered via an epipen, for example) is always the first choice. Antihistamines don’t work fast enough, nor address all the problems caused by anaphylaxis.

Antihistamines may be used later on to calm any hives and itching, once the very serious and acute phase of anaphylaxis has been resolved.

In general, oral antihistamines are not the best treatment to control hay fever – you’re better off with steroid nose sprays. That said, second-generation oral antihistamines can be used to treat mild to moderate allergy symptoms safely on a regular basis over the long term.

Janet Davies, Respiratory Allergy Stream Co-chair, National Allergy Centre of Excellence; Professor and Head, Allergy Research Group, Queensland University of Technology; Connie Katelaris, Professor of Immunology and Allergy, Western Sydney University, and Joy Lee, Respiratory Allergy Stream member, National Allergy Centre of Excellence; Associate Professor, School of Public Health and Preventive Medicine, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Still or sparkling? It’s a question you’ll commonly hear in a café or restaurant and you probably have a preference. But is there any difference for your health?

If you love the fizz, here’s why you don’t have to pass on the sparkling water.

What makes my water sparkle?

This article specifically focuses on comparing still filtered water to carbonated filtered water (called “sparkling water” or “unflavoured seltzer”). Soda water, mineral water, tonic water and flavoured water are similar, but not the same product.

The bubbles in sparkling water are created by adding carbon dioxide to filtered water. It reacts to produce carbonic acid, which makes sparkling water more acidic (a pH of about 3.5) than still (closer to neutral, with a pH around 6.5-8.5).

Which drink is healthiest?

Water is the best way to hydrate our bodies. Research shows when it comes to hydration, still and sparkling water are equally effective.

Some people believe water is healthier when it comes from a sealed bottle. But in Australia, tap water is monitored very carefully. Unlike bottled water, it also has the added benefit of fluoride, which can help protect young children against tooth decay and cavities.

Sparkling or still water is always better than artificially sweetened flavoured drinks or juices.

Isn’t soda water bad for my teeth and bones?

There’s no evidence sparkling water damages your bones. While drinking a lot of soft drinks is linked to increased fractures, this is largely due to their association with higher rates of obesity.

Sparkling water is more acidic than still water, and acidity can soften the teeth’s enamel. Usually this is not something to be too worried about, unless it is mixed with sugar or citrus, which has much higher levels of acidity and can harm teeth.

However, if you grind your teeth often, the softening could enhance the damage it causes. If you’re undertaking a home whitening process, sparkling water might discolour your teeth.

In most other cases, it would take a lot of sparkling water to pass by the teeth, for a long period of time, to cause any noticeable damage.

How does drinking water affect digestion?

There is a misconception drinking water (of any kind) with a meal is bad for digestion.

While theoretically water could dilute stomach acid (which breaks down food), the practice of drinking it doesn’t appear to have any negative effect. Your digestive system simply adapts to the consistency of the meal.

Some people do find that carbonated beverages cause some stomach upset. This is due to the build-up of gases, which can cause bloating, cramping and discomfort. For people with an overactive bladder, the acidity might also aggravate the urinary system.

Interestingly, the fizzy “buzz” you feel in your mouth from sparkling water fades the more you drink it.

Is cold water harder to digest?

You’ve chosen still or sparkling water. What about its temperature?

There are surprisingly few studies about the effect of drinking cold water compared to room temperature. There is some evidence colder water (at two degrees Celsius) might inhibit gastric contractions and slow down digestion. Ice water may constrict blood vessels and cause cramping.

However other research suggests drinking cold water might temporarily boost metabolism, as the body needs to expend energy to warm it up to body temperature. This effect is minimal and unlikely to lead to significant weight loss.

Which water wins?

The bottom line is water is essential, hydrates us and has countless other health benefits. Water, with carbonated bubbles or without, will always be the healthiest drink to choose.

And if you’re concerned about any impact to teeth enamel, one trick is to follow sparkling water with a glass of still. This helps rinse the teeth and return your mouth’s acidity back to normal.

Christian Moro, Associate Professor of Science & Medicine, Bond University and Charlotte Phelps, Senior Teaching Fellow, Medical Program, Bond University

This article is republished from The Conversation under a Creative Commons license. Read the original article.