This was previously posted to my old blog, Itch, Swell, Ooze, Wheeze in March 2015. This is an updated version for 2020.
This allergy makes the Food Standards Agency list of top 14 allergens which needs to be monitored, assessed and declared in food packaging and restaurants in the UK.
When I wrote about the Top 14 allergens last year I found it interesting that Sulphite is not an allergen included in most other countries lists and aside from the EU is only monitored in Canada and South Africa.
Sulphites (or sulfites as they are known in most other countries) are different from other allergens in the top 14 as they are inorganic salts with preservative properties rather than food proteins. Allergy UK estimates that this allergy only affects 2% of the population, but that this can rise in asthmatics up to 13%. This is not usually a classic IgE allergy as the symptoms are usually either from contact in the form of rashes or exacerbating asthma symptoms, so are classed as a sensitivity.
Sufferers may find that they are able to tolerate a low sulphite diet rather than avoiding completely, but it is still important to read labels and be aware of foods which naturally contain sulphites. In the EU Sulphites are to be labelled if they are present in the food at levels above 10mg per kg or 10mg per litre (or if one of its ingredients contains it).
Some wine producers incorrectly assume that their wine is “sulphite free” as they do no add treatments during the production of their wine. Sulphites can be produced naturally during the normal fermentation process, so there is a chance that residual leves of suplhites will exceed to 10mg declaration threshold.
It has been suggested that the best way to diagnose this allergy is through an oral challenge, but it is unlikely that this will be undertaken in the UK. It could be potentially dangerous to patients with a history of severe asthma.
Blood tests are generally unreliable in allergy diagnosis and as sulphite allergy is rarely IgE this is not recommended. There has been some small-scale success with skin prick testing for sulphite sensitivity which is safer.
As with most allergies it is recommended that elimination diets and avoidance are the safest, quickest and cheapest course of action.
It is very difficult to get that initial diagnosis of sulphite allergy, so it’s important to make a note of food which contain it. If you are interested in making a food diary to diagnose or manage your allergy, see my food diary download.
Looking at labels is more difficult with this allergy than it is for the other top 14 as they are hidden in places you wouldn’t expect.
|E222||Sodium hydrogen sulphite|
|E227||Calcium hydrogen sulphite|
|E228||Potassium hydrogen sulphite|
|E150b||Caustic sulphite caramel|
|E150d||Sulphite ammonia caramel|
- Dried fruit
- Jams and Preserves
- Bottled Sauces
- Peeled or dehydrated potatoes
- Pickled Food
- Naturally occurring in onions and garlic
- Fruit Juices
- Hair Dyes
- Fake Tan products
- Skin lighteners
- Local Anaesthetics
- Eye Drops
Did you spot that in the last section? Epinephrine. Sodium metabisulphite is used as a preservative in EpiPend and Jext pens – you can read more about that on the Anaphylaxis Campaign website.
This is a blog and should not be used for advice on diagnosis or treatments.
If you think you may have a food allergy please contact your GP in the first instance to discuss treatment options.