Why do adults suddenly get.. ALLERGIES? Dear Miriam.
As summer gets into full swing, many of us will come down with unexplained sniffles or a nasty rash - and be shocked when the doctor says it's hay fever or a food allergy.
It amazes me that adults are so surprised to discover they've developed an allergy to something. I suppose it's because we tend to associate them with childhood but sudden adult allergies are not unusual - and some scientists think they may be on the rise.
Allergies can develop at any time in your life and can be a reaction to anything.
I used to run an allergy clinic that only treated adults, including people who'd developed allergies to pets, water - even exercise, in one case.
Why adults ignore allergies
A relative of mine developed hay fever at the age of 70 a few years ago. He, like many people, mistook the runny nose and itchy eyes for a "summer cold".
The symptoms lasted for a couple of weeks, then disappeared and he forgot all about it. It was only the following summer - when the same symptoms returned but lasted longer - that we finally realised it was hay fever, even though he'd never had it before.
But, while delaying a diagnosis of hay fever might not be the end of the world, ignoring symptoms of a more serious allergy could be dangerous, which is why adults must be vigilant.
What to watch out for When it comes to allergies, symptoms tend to get worse each time - an escalation known as the "allergic march" - so it's important to see your GP if you suffer any of the following... Runny nose or nasal congestion: This can be triggered by an airborne allergen such as pollen, dust or pet dander.
Itchy, swollen eyes: This can be due to allergens such as pollen entering the eyes, or from using a new eye cream. A red and white, raised rash: Known as urticaria, this looks like nettle rash and disappears after 20 minutes. It's almost always a sign that you've had an allergic reaction to something you've eaten. Swelling of the lips, tongue and/or face: This is the rarest but most dangerous kind of allergic reaction and can come on very quickly.
It can be the result of eating a food such as peanuts or shellfish, from taking certain medication or from a wasp sting. It can quickly develop into anaphylactic shock, in which the throat and airways swell and breathing becomes difficult. It can kill in minutes, so you must get to hospital immediately.
"But I've eaten peanuts before!"
Contrary to popular belief, an allergy always develops to something you've been exposed to before, so don't think you can't become allergic to peanuts just because you've eaten them many times.
An allergy happens when antibodies in our immune system overact to something harmless they see as a threat. They trigger the production of histamine, which causes the symptoms we associate with allergies. But, to produce antibodies in the first place, your body must have encountered a substance at least once before.
Why adults get allergies
Here are some reasons: They run in the family: Allergies seem to have a genetic component. Many people find, when they ask their parents, that there's a history of allergies in the family.
Life today is too clean: Our immune system needs constant stimulation to stop it over-reacting to safe things. Overuse of antibacterial products and general overcleanliness may prevent this vital stimulation happening. You took a lot of antibiotics as a child: Some studies suggest this could make you more likely to develop allergies as an adult.
Why a sudden reaction?
We're not sure exactly but a sudden allergy in adulthood nearly always happens after something has shaken up the immune system, including any of the following: You've had a strep throat infection.
You've been through a serious illness or operation.
You've recently been through the menopause.
Your body has been through a period of extreme emotional stress such as bereavement or divorce.
Your doctor may want to do an allergy skin test. Treatment then involves avoiding known allergens, plus - depending on symptoms - the use of antihistamine, nasal sprays and decongestants.
If you have a severe allergy that puts you at risk of anaphylactic shock, you'll need to carry an adrenaline jab with you at all times.
I developed hay fever at 35
Vanessa Sterling, 35, is an art curator from London. I was walking down the street at the beginning of spring this year when I first noticed the symptoms.
My eyes were sore and swollen, and my nose felt blocked. I had no idea what was wrong and thought I might be getting a cold.
I carried on as normal, putting up with feeling poorly until I mentioned it to my fiance, Patrick. He suffers with allergies and said: 'You know what, it sounds like hay fever.'
I thought he must be wrong as I'd never suffered from any sort of allergy - I'd assumed you only developed them as a kid. But, with a cold ruled out, I went to the pharmacist and he agreed with Patrick and suggested I tried some antihistamine. Within an hour, my eyes had calmed down and my nose was clear. My doctor then confirmed the diagnosis.
Now, when it's windy and the pollen is blowing off the trees, my hay fever gets really Sometimes, it stops me working as my eyes are so swollen, I can't look at my computer screen.
I've no idea why it developed so suddenly, although I've had a stressful year planning a wedding and moving house.
Talking to my family, I've since discovered that my mother developed an allergy to pollen in her 50s, so maybe it runs in the family. I just hope it doesn't get any worse.