Same as linseed!
Found in smoothies, bird seed balls, dog food, varnish, and omega 3 supplement capsules!
No cross reactivity with other seeds eg sesame!
Category Archives: Immunology
Bell pepper allergy
The names get confusing!
Bell peppers or sweet peppers (capsicum) come in red, yellow and green varieties. The colour just tells you how ripe it is, they are the same thing!
They are related to potato, tomato, aubergine, latex (the nightshade family). You are not automatically allergic to all of these things, but you may have a higher risk if you are already allergic to one or more of them.
Chilli peppers are closely related to bell pepper. There are lots of different ones, both red and green eg bird’s eye, Scotch bonnet, jalapeno, chipotle.
Chilli powder, paprika, cayenne, pimento are all spices made from these plants, so if you are allergic to the vegetable there’s a good chance you will react to these spices too. These get used to make pepperoni, salami, chorizo sausage and others.
Black and white pepper are completely unrelated! You do not need to avoid these.
Cross contamination can be a big problem, since in restaurants, the same knife and chopping board will get used for chopping bell peppers and all other vegetables. Chargrilled food is also a risk if cooked on the same surface as roast peppers! Ask restaurants to use separate knives, chopping boards, frying pan etc.
Ketchup, baked beans, BBQ sauce, crisp flavourings, stock cubes, soups are all potentially a problem, as are most ready meals, you will need to look closely at the ingredients label.
Paprika extract is used as red/orange colouring in lots of things.
You might need to avoid anything with unidentified ‘spices’ or ‘flavourings’ until you can get further details from the manufacturer.
You may not react if the amount of spice used is very low, but this is hard to predict and you may find that one time you don’t react but another time you do react to the very same thing.
Abroad, food can be very different and you need to be much more careful. In Serbia and Croatia, for instance, there is a traditional tomato sauce ajvar that often gets served on the side of meals, which is made with red peppers.
(With thanks to Julia Marriott)
Celery Spice Mugwort syndrome
An allergy syndrome, where there is cross reactivity between mugwort (a pretty nondescript weed, pollen can cause hay fever and trigger asthma) and a wide range of foods, including:
- Fruit – esp apple, melon, peach, orange, watermelon
- Tomato
- Vegetables – esp celery, carrot, green pepper, onion, parsnip
- Spices – eg mustard, paprika, pepper, coriander, basil, dill, oregano, parsley, thyme, anise, caraway, fennel, tarragon
- Chamomile
- Sunflower seeds
You are not automatically allergic to everything, just be aware that you are at higher risk of being allergic to something else on the list if you are allergic to one or more things.
Oxo stock cubes better than others?
Mustard allergy
One of the 14 ingredients that must be highlighted on EU food labels.
Probably more common in France, not much data for UK but seems rare.
One of the spices that has cross reactivity with mugwort so look for other foods causing problems, as in celery spice mugwort syndrome.
Used in lots of different cuisines across the world eg black mustard seeds in curry, not just mustard as used on hot dogs and sandwiches. Also a key ingredient in:
- mayonnaise (more usually the egg causes problems but could be either or both),
- ready meals and other prepared foods,
- Salad dressings,
- Honey and mustard sauce eg for chicken, gammon,
- Chutneys,
- Pickles eg gherkins
Sometimes mustard leaf gets used as a vegetable!
Nightshade family
Vast group of vegetables. As with all cross reactivity, allergy is not automatic but being allergic to one or more increases the chance you will be allergic to another.
- Tomato – but see also salicylate intolerance
- Aubergine – can contain histamine like chemicals!
- Bell pepper (capsicum) – from which you get the spice paprika, often used in other things eg salami, pepperoni
- Chilli pepper
- Potato (but not sweet potato). Raw potato is sometimes the problem (contact, obviously) rather than cooked.
Vaccine allergy
The most common adverse events of vaccines are fever, local pain or irritation, and local redness or swelling, which are not signs of allergy
With live vaccines, adverse effects can be delayed until 7 to 21 days after immunization; this includes vaccine-induced delayed-onset urticaria, which is commonly mistaken for allergy.
Assessment and allergy-focused clinical history
- Testing appropriate for all, whether anaphylaxis, mild symptoms, unknown history or family history.
- Gold standard is an oral challenge with a therapeutic dose of amoxicillin, 1hr observation, then 5 day course at home to ensure no delayed reaction.
- Low risk individuals, where IgE mediated reaction unlikely, can go direct to challenge without testing.
- Puncture and intradermal skin testing is recommended where reaction was within last 12 months, or there were respiratory symptoms.
- Skin testing using only penicilloyl-polylysine, with at least 5 mm of wheal and flare greater than wheal as the criteria for a positive test result, is now sufficient to rule out a high risk of having anaphylaxis during a confirmatory oral amoxicillin challenge
Egg is used in the manufacture of a number of vaccines. Whether this is clinically significant or not depends on the vaccine and the severity of the allergy:
- MMR – only contraindication is anaphylaxis to MMR or other constituent of MMR vaccine
- Influenza – (live nasal or inactivated injectable) patients with “severe anaphylaxis” (ie requiring intensive care) should be vaccinated in hospital.
- Varicella, Rabies – no contraindication for egg allergy
- Yellow fever – discuss with specialist if egg allergy
Gelatine (derived from pork or beef) can be a cause of allergic reactions esp MMR, Varicella, Japanese encephalitis. Allergy would usually be established from history of food reactions eg gummy/jelly sweets, marshmallows.
Latex – can be present in syringe or bung. See Latex allergy.
Despite these potential causes of allergy, immunisation can often be achieved through graded administration.
Some reports of persistent itchy nodules at injection site due to aluminium delayed hypersensitivity.
Fruit allergy
A range of possibilities!
- Isolated type 1 allergy
- Multiple type 1 fruit allergies – usually to similar fruit but also some common co-sensitivities eg banana/melon/avocado/chestnut/latex group
- Oral allergy syndrome (pollen food syndrome) – esp peach and related stoned fruit, cross reactivity with pollen (so hay fever), sometimes nuts too. Various patterns depending on allergen family.
- Salicylate intolerance (so not allergy) esp cherries, raw tomato, pineapple juice
- Histamine-releasing foods (wine famously, otherwise strawberry, papaya, kiwi and pineapple)
- Naturally occurring serotonin (tomato again, banana) and tryptamine (tomato again, plum) cause allergy like symptoms [EAACI 2023]
Berry allergy
Some evidence of cross reactivity between raspberry and strawberry but there’s not much evidence to suggest cross reactivity with other berries. There’s a theoretical link with blackberry, and other things in the same family (Rosaceae – massive group of fruit including apples, peach, pear, apricot, cherry).
Only one report of blueberry allergy ever!
Found one paper that said tree nuts, celery and parsley might also be related to berries, but again I think theoretical.
Pineapple allergy
Can be part of pollen food syndrome (due to profilin allergy) so mostly oral symptoms, hay fever, cross reactivity with other fruits as well as nuts.
Might be salicylates as above rather than allergy.
But can also be allergy to bromelain (similar to papain), with potential for anaphylaxis.
Sometimes associated with latex-fruit syndrome and ficus-fruit syndrome (all tropical, not latex – kiwi, papaya, avocado, banana).
Melon allergy
Can be part of banana/latex group, but also cucurbitae – watermelon, cucumber, courgette, pumpkin.
Salicylate intolerance
Can cause allergy like symptoms eg wheezing, itching, swelling, nasal congestion. Also headaches, abdo pain. Anaphylaxis reported.
Found in foods, medicines, beauty products.
High levels:
- Cherries and strawberries, tomato (raw)
- Ginger, mustard, curry powder (?)
- Liquorice and mint
Pineapple juice high but fruit itself not listed!?
Medium:
- Black pepper
- Sweetcorn
- Fizzy drinks
- Ketchup, Worcestershire sauce
- Honey
Benzoates related. A variety of other foods esp fruits but also avocado, vegetables, nuts, coffee, beer too.
Management
If suspected, exclude high salicylate foods only to begin with, and limit medium salicylate foods if possible. 4/52 minimum. Includes topical including anything with “Natural plant extracts”.
If improves, excluded medium too for further 2/52 to see if additional benefit.
(draft BDA FAISG)
Lowest Observed Adverse Effect Level
“Highly allergic” or “severely allergic” can mean low threshold for reacting, or severe previous reaction, or both!
Lowest observed adverse effect level is the formal term for the minimum dose at which you react! An eliciting dose (ED) can then be calculated through multiple food challenges for a stated proportion of the allergic population. For example, 1 peanut =150mg protein. ED 1 (where 1% of allergic population will react) is 1.3mg. But range of reported values – type of peanut allergy? Entry criteria? Boiled or roasted? Criteria for stopping challenge?
Higher eliciting dose predicts future tolerance, at least for milk and peanut, maybe not for egg.
Children probably more sensitive although ED 10 similar for children and adults.
Conflicting evidence on severity of reaction vs threshold. Certainly trace amounts can cause anaphylaxis in some cases. Higher fat content delays absorption, so the reaction (when it happens) can still be severe…
ED05 of 1.5mg for peanut seems safe [Hourihane].
Being cross allergic to other things might help predict – in French study, 3 phenotypes emerged from cluster analysis:
- Cluster 1 have high level of rAra h 2 (mean 81), low threshold reactive doses for peanut and high proportion of asthma;
- Cluster 2 (mostly boys), have high threshold, milder symptoms, and the lowest proportion of asthma/AR and cross-allergy to TN and/or legumes;
- Cluster 3 have low Ara h 2, high risk of cross-allergy to TN and/or legumes, and most patients suffer from eczema. [Matthias Cousin, Lille, PAI]
Complicated though – thresholds vary up to 10x for individuals in sequential challenges (n=14)!
On the day factors – alcohol/meds, infection. Exercise is a factor in 15-20% of anaphylaxis episodes according to German/Austrian registries.
TRACE peanut study – 45% reduction in threshold for exercise and sleep deprivation (independent) esp at lower eliciting doses. ED1 and ED5 remain above 0.2 though.
Sleep deprivation (sleep overs!) worsened severity of reactions too, by 48% – exercise 28%, not significant. Repeated challenges also seemed to increase severity. [score for severity using Practall criteria. JACI 2022 Dua]
Lower thresholds had higher BAT and SPT – 8mm cut off had 100% sensitivity and NPV for severe reactions, and 92% specificity. Has nomogram combining all tests! SPT 6mm had 92% sensitivity, 95% specificity and 100% NPV for low threshold. [JACI 2020, Santos study – LEAP cohort]
Particulate contamination risk seems to be a particular problem for milk in chocolate – big range of values found cf peanut.
UK and Europe look at processes as the way to assess risk of contamination with allergens. But not consistent between countries of the EU, let alone globally.
Quantitative methods would appear to make sense – how much allergen is actually present in a given sample? But of course one sample may differ from another (“particulate contamination”). Also difficult to establish minimum eliciting or threshold dose (consider denaturation of the allergen during processing, derived ingredients eg glucose syrup from wheat, soya lecithin, effect of food matrix, individual factors).
Australia and NZ use lowest observable adverse event level (LOAEL) already – warnings required within 10x concentration of LOAEL (“VITAL” threshold, as in toxicology). Studies from Europe and US have found most advisory warnings used for ingredients below the VITAL threshold.
But then it depends on how much you eat, as well as presence of other co-factors that are known to contribute to risk of anaphylaxis.
[BMJ 2011;343:830][Allergy 2021, Paul Turner]
Coconut allergy
Not a true nut (along with chestnut, pine nut, tiger nut, doughnut etc), classified as a fruit, from palm family. Allergy is pretty rare, but is possible, usually only seen in people with other allergies. Associated with macadamia, almond, walnut, hazelnut, lentil and latex allergy.
The major allergens are storage proteins (7s globulin=vicillin like), so not affected by heat.
In EU, does not have to be specifically highlighted on labels, but in US FDA do include it under nuts!
Other names , particularly when used in cosmetics:
Cocos, cocamide sulphate, cocamide DEA, CDEA, Cocamidopropyl betaine.
People who react when they eat coconut don’t necessarily have a problem with it on their skin, but this may depend on whether they have eczema. Where people do react to skin products, complicated, because one of the intermediates in manufacturing (found at very low level) appears to be a more likely cause of type 1 reactions than coconut itself or one of the listed coconut derivatives.
Contact dermatitis triggered by coconut much more common than type 1 allergy.
Sources of coconut:
- Fruit smoothies
- Snowball type sweets
- Bounty chocolate bars and similar
- Indian or other Asian sweets
- Some flavoured rums eg Malibu, and cocktails eg Pina Colada