Dr. Adrian Morris of Surrey Allergy Clinic Tests and Treats allergies » Allergy Testing

Insect sting allergies

Dr. Adrian Morris — Mon, 03 Oct 2011 14:39:19 +0000

A recent venom allergy guideline¹ published by the British Society for Allergy and Clinical Immunology (BSACI) this year, makes interesting reading. They report a lifetime-risk between 60 and 90% for the UK population of being stung by a wasp (Vespid) or bee (Apis). Of those stung, up to 26% will report large painful local reactions, but significant allergic reactions only occur in about 7% of those stung (bee-keepers being a very high-risk group with severe reactions reported in 30% of those stung). Although wasp venom allergy is more common in the UK, bee-stings carry a higher risk for anaphylaxis. Any patient with a severe reaction to an insect sting should be tested for both bee and wasp venoms sensitivity, as dual-positive IgE antibodies to both insects occurs in 30%, even though they may report being clinically sensitive to only one insect. Venom desensitisation immunotherapy (VIT) or “allergy shots” are highly effective in those severely sensitive to insect stings, resulting in a cure for 95% of wasp and 80% of bee venom allery sufferers treated over the 3 year programme. Older people are more likely to develop life-threatening anaphylaxis and fatal allergic reactions (at an average age of 50 years). Children are less prone to have life-threatening allergic reactions to insects, and 80% of children with a mild venom allergy with tolerate further stings and outgrow their allergy. Once sensitised, reactions are likely to be the same in 45% stings, milder in 43% and more severe in only 12%. Fatal reactions after insect stings are rare (47 deaths in UK over a 10 year period from 1992-2001)

¹Reference: Krishna MT, Ewan PW, Diwakar L, Durham S, Frew AJ, Leech SC and Nasser SM. Diagnosis and management of hymenoptera venom allergy: British Society for Allergy and Clinical Immunology (BSACI) guidelines. Clinical and Experimental Allergy 2011:41; 1201-1220

Testing for allergies to metal implants

Dr. Adrian Morris — Mon, 03 Jan 2011 11:58:14 +0000

Many surgical procedures involve implanting artificial metallic components such as joint replacements (arthroplasties), plates, screws and internal “plumbing” that contain metals such as titanium, nickel, cobalt and other heavy metal alloys. Ever since mercury dental amalgam was thought to be a health hazard in the 1970’s, people have become very aware of possible side effects of foreign metallic implants. Although implants are now commonly used, there seems to be no convincing evidence that they cause local or systemic allergic or immunological problems. Some clinics offer blood tests and skin patch tests for possible heavy metal toxicities, but it must be pointed out that these tests are not scientifically validated and offer no proven diagnostic aid. They increase anxiety and lead to many people declining quality of life improving procedures such as a hip or knee repalcements for crippling arthritis, or worse still, the unnecessary removal of such prosthesis.

Reference: American Academy for Allergy and Clinical Immunology (AAAAI) website: http://www.aaaai.org/professionals/ask-the-expert/view.asp?id=9944

Cow’s milk allergy may be misdiagnosed in babies

Dr. Adrian Morris — Mon, 06 Dec 2010 08:15:37 +0000

Cow’s milk allergy is relatively common in babies (1:50) but rarely develops after one year of age. Symptom improvement on a cow’s milk-free diet and recurrence of symptoms with reintroduction of cow’s milk formula is the most accurate diagnostic procedure. Cows milk allergy may be underdiagnosed as it is common (but misguided) practice amongst UK GP’s and Paediatricians only to perform food allergy testing in children once they are 4 years or older.

Skin prick tests using fresh cow’s milk and RAST blood tests for cow’s milk protein IgE antibodies are the only reliable tests and have 60-90% accuracy. The whey (liquid) fraction of milk tends to cause most allergies, but the casein (curd) fraction triggers more severe and persistent allergies.The higher the milk-specific IgE level, the more likely there will be a clinically relevant milk allergy. High levels of Casein specific IgE antibodies indicate a higher risk for severe cows milk allergy and also for persistent cows milk allergy, On the other hand, IgG antibody testing for cow’s milk proteins (casein and b-lactoglobulin) is of no allergy diagnostic value and merely indicates exposure.

The clinical history and observation of the infant feeding are very helpful, and a family history of atopy increases the likelihood of a food allergy. Cow’s milk allergy can manifest with immediate urticaria and facial angioedema and respiratory, oral and laryngeal symptoms, as well as deteriorating eczema in addition to typical intestinal symptoms such as vomiting, diarrhoea, persistent reflux, food refusal and even anaphylaxis in severe cases.

Mildly milk-allergic infants often tolerate small amounts of processed dairy produce such as yoghurt and cheese as well as Goat’s milk. Infants with severe cow’s milk allergy will react to any traces of milk protein in partially hydrolysed milk formula, cooked foods and even breast milk, as well as any skin contact with milk proteins.

Outgrowing egg allergy

Dr. Adrian Morris — Mon, 26 Jul 2010 11:26:33 +0000

Hen egg allergy is very common in infants with eczema and usually outgrown by age 6 with a few children retaining their egg allergy into adulthood. The egg white or albumin is more allergenic than the yolk and heat or cooking damages the allergen making it less allergenic. Some children will therefore tolerate cooked but not raw egg, whereas other more severely allergic children will react to all traces of egg. Early onset of egg allergy is associated with asthma at age 18 months. Fortunately the Measles (MMR) vaccine no longer contains any egg so is not contraindicated in egg allergic children. However the Influenza and Yellow Fever vaccines are grown on chick egg embryo’s and therefore may be a problem for egg allergic children.

A new ImmunoCAP f233 blood test can now determine whether hen’s egg allergy is likely to be severe and persists into adulthood. Once the IgE skin prick test or blood RAST testing show a positive allergy result for eggs, a further test for raised antibodies to the heat-stable egg protein Ovomucoid (Gal d 1) is very useful for determining if egg allergy will persist.

Ref: Ando H, Moverare R, Kondo Y et al Utility of ovomucoid-specific IgE concentrations in predicting symptomatic egg allergy. J Allergy and Clin Immunology 2008:122;583-8.

High Street allergy tests mislead public

Dr. Adrian Morris — Mon, 22 Feb 2010 19:07:01 +0000

The Sunday Times newspaper has again produced a masterpiece of investigative journalism (Sunday 21st February 2010) highlighting the frightening number of nonsense allergy and food intolerance tests available in central London. It is amazing that there is no public watchdog to prevent these unvalidated and unscientific allergy tests from being promoted to unsuspecting members of the public by inadequately trained practitioners and nutritionalists. Well done to Gillian Passmore and the Sunday Times for again drawing attention to the issue of misleading unorthodox allergy testing.

http://www.timesonline.co.uk/tol/life_and_style/health/article7034867.ece