Category Archives: Immunology

Food Challenges

Gold standard for diagnosis of a food allergy or intolerance. The suspect food is strictly excluded for a period, generally not less than 2 weeks, and then the food is re-introduced. Symptom control during this process should confirm or refute the diagnosis. The challenge is only considered complete once a normal age-appropriate portion of the food has been consumed.

In certain cases, food challenge is potentially more dangerous, and should only be done in a specialist setting with emergency support immediately available, and if there is a moderate to high risk of a severe reaction, intensive care support should be immediately available:

  • Where the initial reaction sounds severe (anaphylaxis or FPIES)
  • Where the patient has asthma

The challenge can be blinded if there is still doubt. Objective measures of symptoms/signs may be required. Eczema, wheeze, congestion, diarrhoea should all have resolved prior to doing the challenge, to avoid potential confusion.

The risk of causing a reaction should be weighed against the potential benefit of removing dietary restrictions and reducing fear/anxiety.

[EAACI food allergy diagnosis, Allergy 2014]

Honey in medicine

Contains a range of different sugars, aromatic oils, also pollens and bee proteins. Royal jelly and beeswax related, of course.

High fructose content can cause GI intolerance in some.

Allergic reactions can happen, often unrecognised, either to specific pollens (depending on what flowers the bees feed on) or bee proteins. IgE test for honey is available, but you may need to skin prick test with the specific honey if negative.

Honey eaten all year round is rumoured to prevent hay fever symptoms because of the pollens it contains, but this has not been proven, although it’s a nice idea related to immunotherapy. Depends on getting the right pollens of course – bees don’t like grass and birch flowers, probably. In some it may just trigger allergy symptoms.

Cross reaction between honey and bee venom is reported, not surprisingly, but not automatic.

Plant toxins can be present in sufficient quantities in honey to cause poisoning eg rhododendrons (some species).

Botulism reported in infants – failure to thrive, hypotonia, cranial nerve palsies. Clostridium and other bacteria cannot grow in honey due to the high sugar content, but spores can be present. So advice is not to give honey to infants.

Allergy Plans

People with a food allergy or who have had a previous severe reaction (anaphylaxis) to anything should have a written plan, describing clearly what they should do if they have a reaction.  This should be completed by your doctor or allergy professional.

This plan should be reviewed every year, to check that the names and doses of medicines are correct, and that it includes a blue inhaler if you have one.

The British Society for Allergy and Clinical Immunology (BSACI) and Royal College of Paediatrics and Child Health have published an allergy plan template that can be completed online and printed, with different versions depending on whether you have been prescribed an adrenaline autoinjector, and which one you have.

Your allergy clinic may have their own version. The BSACI one has the advantages of being in colour, it also includes (in very small print) parental authorisation for a school to administer an autoinjector (technically not legally required of course, but might overcome hesitancy), and a comment about having autoinjector in hand luggage on a plan. It also includes a link to the Spare Pens in School website. But it doesn’t emphasize carrying your medication at all times, and doesn’t allow for a second dose of antihistamine unless you vomit the first one.

The plan should list the different signs and symptoms of a reaction, and make it clear which signs and symptoms should alert you to the possibility of a severe reaction.  It should then give clear advice on whether you can give medicine and wait for things to get better or whether you should be using your adrenaline autoinjector (if you have one) and phoning 999.

The plan should ideally stay with your allergy medicines and your child, wherever they go.  You may need copies for other people who help look after your child, for instance grandparents, child minders, nursery and school, after school care. Getting your plan laminated can help it stay legible!

Schools may also want to have a written document that details what extra precautions are necessary in the school environment or on school trips.

Allergy plans are also available from the Epipen and Jext websites, for families who have those adrenaline autoinjector devices.

Safe Food Skills for Allergy

  • Ask about ingredients of unfamiliar food
  • Declare allergy in restaurants, cafés, when ordering take away food (preferably to real person rather than app/website)
  • Inform family and friends about allergy
  • Don’t accept food if unclear what the ingredients are
  • Read ingredients labels #EveryLabelEveryTime
  • Consider the risk of items with “may contain” warnings
  • Appreciate risk of contamination of surfaces/utensils/hands
  • Carry allergy medicines and plan when out of home/school

Allergy and Transition

Although transition is usually meant to describe a process of passing on medical care to an adult service for a chronic condition, with allergy things are a bit different. Firstly, the diagnosis is often made at a very young age and the child may have lived with it for many years before the age where transition processes generally kick in (around 11-13yrs, often coinciding with move to high school), so they may already be very aware of their condition.

Secondly, there is often no need for adult allergy service input, and in some areas eg Eastern Scotland there is no adult allergy service anyway.

The challenge is that young people want independence from their parents, self – determination, at the same time they want to fit in with their peers. It is the developmental task of adolescence to have new experiences (even if they are not as bullet proof as they might imagine), including sexual/intimate relationships. It is normal, indeed appropriate, for them to challenge authority/norms, take risks, experiment, demand rights.

When it comes to allergies, bad eczema may already have affected self-image, self-esteem, caused social isolation.  Asthma may have reduced participation in sports, and has its own negative stereotypes.

It’s sometimes productive to go back in the history, especially where there is a history of anaphylaxis – how much is chronic parental anxiety, how much terror of further reaction. 

Non-judgmental approach important.  Particularly important for a young people to be treated as an individual.  When it comes to risks and safety, key in allergy, it’s all about balance – fear of reaction vs being “normal”.  Requires negotiation.

“I have found the best way to give advice to children is to find out what they want and then advise them to do it.” [Harry Truman]  “When I was a boy of 14, my father was so ignorant I could hardly stand to have the old man around. But when I got to be 21, I was astonished at how much the old man had learned in seven years”. [Mark Twain]

EAACI has 2020 guidance, combined allergy and asthma, by Graham Roberts in Southampton. Key points are:

  • Do you use a structured multidisciplinary transition programme for allergy?
  • Do you use a checklist of skills and knowledge to assess readiness for transition?
  • Do you communicate with your young persons via text or other mobile technology?
  • Do you discuss exams and impact of allergic rhinitis?
  • Have you had any specific teaching or training in transitional care (generic and/or allergy specific)?
  • Do you recommend any specific websites or apps for allergy advice/support?
  • Do you focus consultation on areas where young person says they are not confident?
  • Do you provide (“formulate”)  a personal allergy plan?
  • Do you offer information about any peer-led interventions?
  • Do you discuss exams and impact of allergic rhinitis?
  • Do you recommend any specific websites or apps for allergy advice/support?
  • Do you focus consultation on areas where young person says they are not confident?
  • Do you provide (“formulate”)  a personal allergy plan?
  • Do you identify psychosocial issues, using a tool such as YouthCHAT (online, 8 mins) – includes physical inactivity, eating disorder, problems at home, sexual health etc.
  • Do your friends understand you have an allergy and how to manage an emergency?
  • Do your teachers understand you have an allergy?
  • Do you signpost to high quality online resources?  Do you discuss the role of social media [ie how moderation is desirable, to keep chat positive]
  • [other stuff more relevant probably to asthma]

CYANS is similar, suggesting bite sized topics including:

  1. Do you confirm that they know their diagnosis accurately, and are not avoiding any foods unnecessarily?
  2. Do you discuss specific foods/cuisines that they need to be careful with?
  3. Do you discuss the potential risk from foods labelled “May contain…” or with similar precautionary labels?
  4. Do you discuss experience of food shopping and cooking?
  5. Do you check how confident they feel explaining their allergy to others?
  6. Do you discuss the potential for alcohol to increase the risk of anaphylaxis?
  7. Do you discuss the potential risk from kissing?
  8. Do you present a scenario of an unexpected reaction, to check their understanding of anaphylaxis symptoms and appropriate self management?
  9. Do you see them alone (with parental agreement)?


Brand name for processed peanut flour, AR101 (now called PTAH – PeanuT Arachis Hypogaea), used for peanut immunotherapy.

Defatting process supports storage conditions, pharmaceutical processing for protein content and consistency, and may remove some of the peanut flavour.

NHS England has approved it for use but only in 600 children in the first year, then 2000 the year after.

Aim is not to “cure” peanut allergy, though – but to “mitigate against severe reactions” (ie anaphylaxis) if you accidentally come into contact with peanut.

Hyper IgM syndrome

A group of primary immunodeficiencies characterised by inability to class switch, so high IgM but low IgA and G, leading to susceptibility to infection but also autoimmune problems.

Misnomer because high IgM is a clue but not always found!

Various inheritance patterns but mostly X-linked so variable penetrance/severity. Most affect CD40 ligand production.

Usually presents in infancy – skin, lung, sinus, eye infections. Particularly prone to Pneumocystic pneumonia, histoplasmosis, cryptosporidium.

  • Bronchiectasis seen
  • Histoplasmosis leads to fever, cough, lymphadenopathy
  • Chronic cryptosporidium diarrhoea, progressing to cholangitis and cirrhosis
  • Failure to thrive
  • Warty or chronic papular rash
  • Osteomyelitis a particular problem for type 4 where there is less susceptibility to infection otherwise and presentation can be later in life.


  • Neutropenia
  • Thrombocytopenia
  • Thyroid disease
  • Kidney disease
  • Inflammatory bowel disease


Increased rate of various malignancies seen.

Grape allergy

Commonly associated with apple, peach, cherry allergy (rosaceae).

You can be allergic to some grape varieties but ok with others. Some may be allergic to grape but not wine, whereas others might not tolerate grape, wine or raisins/sultanas/currants.

Apart from wine, there’s also white wine vinegar, and vine leaves (stuffed in Greek and middle eastern cuisine!

Some people complain of bloating with grapes, this is usually fructose intolerance rather than allergy.

Reactions to wine (symptoms such as flush, rhinitis, asthma, and migraine) are not rare, but can be caused by different things:

  • type 1 immediate allergy to grape
  • type 1 immediate allergy to moulds (“the noble rot” for example is a mould that gives Tokay and Sauternes their character)
  • intolerance reactions to histamine and sulphite.

LTP sensitization seen, associated with anaphylaxis.


Substantial evidence that alterations in the gut microbiome early in life “imprint” gut mucosal immunity, which is probably important for development of food allergy.

Maternal factors, timing and how solids introduced all likely to be important.

Experimental studies have shown that faecal transplants or other attempts to modify bacterial commenals can prevent or treat food allergy.

Mechanisms include restoration of gut immune regulatory checkpoints (eg retinoic orphan receptor gamma T+ regulatory T cells), the epithelial barrier, and healthy immunoglobulin A responses to gut commensals.

[Rima Rachid, JACI 2021]

Lanolin allergy

Prob less common than suspected or talked about in eczema circles. Allergy to medical grade lanolin particularly uncommon, cf raw wool.

Patch testing pretty non reproducible! Not all lanolin the same?! Presence of alcohol important?!

So some v vocal critics of allergy “panic”!

Lanolin in cosmetics tends not to cause any problems, presence of damaged skin may be important for reactions.

For moisturisers, the following are lanolin free:

  • Aveeno
  • QV
  • Hydromol ok too?
  • [Not E45]

For bath additives, the following are lanolin free:

  • Cetraben
  • Diprobath
  • Balneum
  • Doublebase
  • Hydromol
  • Dermol 600
  • [Not Oilatum]

Steroid creams seem to be ok, at least Eumovate, Betnovate, Fucibet.