Dr Sarah Jarvis
My Weekly’s favourite GP from TV and radio writes for you
Allergies are really common – hay fever for instance is an allergy to pollen. Many rashes are an allergic reaction to things your skin comes into contact with.
Many allergies are minor but irritating, and can be dealt with using steroid (cream for skin, sprays for noses etc). But severe allergies can be life-threatening.
There are two main types of allergy, and the possible outcomes are completely different. Allergies are caused by an overreaction from your immune system – largely provided by the white blood cells in your body, which help fight off infection.
An IgE (Immunoglobulin E) reaction is rapid, often severe, even life-threatening – more later. A non-IgE reaction is delayed and can affect just one part of your body. Dermatitis means inflammation of the skin. Contact dermatitis causes a red, sore, sometimes itchy or scaly rash. Only one sort is due to allergy – you can also develop “irritant” dermatitis from strong cleaning products, solvents and some plants. Common causes of allergic contact dermatitis include nickel (in jewellery, belt buckles etc); cosmetics (including nail varnish and hair dyes); preservatives or perfumes in creams; and plants such as sunflowers, tulips and daffodils. You don’t start life allergic; your immune system is primed at some point to react. But once you’re allergic you should avoid the trigger for life. Allergic dermatitis can take hours or even days to develop so it can be hard to tease out the cause. You may be sent for “patch testing” (tiny
DIARRHOEA OR VOMITING WHEN YOU TAKE AN ANTIBIOTIC ISN’T DUE TO ALLERGY AND DOESN’T MEAN YOU NEED TO AVOID THAT ANTIBIOTIC FOREVER.
amounts of possible allergens are left on your skin to see what you react to). Treatment for both types involves steroid creams, moisturisers and avoiding the culprit.
Food intolerance is never life-threatening. It affects only the gut – wind, bloating, tummy pain, feeling sick and diarrhoea, for instance. You need not avoid the food completely and may not get symptoms if you have a small amount. If you have lactose intolerance, you might be fine with a cup of tea but suffer after eating a yoghurt.
Anaphylaxis is the most serious type of allergic reaction. Common causes include foods such as nuts, eggs, shellfish, strawberries, kiwi fruit; medicines including antibiotics, codeine-related medicines and aspirin; bee or wasp stings; and latex.
Anaphylaxis has been in the news after the tragic death of a young woman allergic to sesame who unknowingly ate the seeds in a sandwich. The symptoms come on in minutes and worsen rapidly. They include an intensely itchy, blotchy rash; swelling of tongue, throat and lips, which can block your airways; wheezing, hoarseness, feeling faint, palpitations, vomiting, diarrhoea, a sense of doom and collapse. It can be fatal so call 999 immediately.
If you’ve ever had this sort of serious reaction, you should be referred to an allergy clinic for testing – people who have an anaphylactic reaction to one thing are often allergic to others. You must avoid the slightest trace of whatever you are allergic to forever, and always carry an adrenaline pen (brands include EpiPen®, Emerade® and Jext®). It’s a good idea to wear an allergy bracelet.
Show people you spend most time with how the pen works, and where you keep it. They should also be trained in resuscitation. Next week: Immunisations And Vaccinations
IF YOU’VE EVER HAD A RASH FROM PENICILLIN YOU NEED TO AVOID EVERY KIND OF PENICILLIN FOR LIFE, AND BE WARY ABOUT SOME OTHER ANTIBIOTICS.