Allergy Articles

In a study, published in the British Journal of Dermatology¹, a team of researchers in Denmark² looked at the incidence rate and persistence of contact allergy and allergic contact dermatitis in a group of 8^th grade school children followed up 15 years later.

The study showed that cases of allergic contact dermatitis to nickel had not only persisted but had increased in number - despite increased awareness and preventative measures having been introduced, such as the EU Nickel Directive.

Contact allergy and allergic contact dermatitis occur when the skin comes into contact with a specific contact allergen in the environment – commonly things like nickel, perfume in cosmetic products, ingredients in hair dye. It is a condition that can have a big impact on sufferers lives and may affect their ability to work, accounting for 70-90% of all occupational skin disorders.³

Deborah Mason, spokesperson for the British Association of Dermatologists, said: “It is interesting that this study found that nickel was still the most common contact allergen, with new cases occurring despite the EU Nickel Directive that limits the amount of nickel released from items of jewellery. The British Society for Cutaneous Allergy has recently publicised its concern that the Royal Mint are producing nickel-plated coins in the UK⁶. Whilst this may not contravene the EU Directive, the continuing prevalence of nickel as a contact allergen in the general population adds to concerns about nickel in coins and the risk of allergic contact dermatitis especially in people who handle coins at work.”

This study was the first to study both contact allergy and allergic contact dermatitis developing from adolescence to adulthood. To do this the research group had access to the Odense Adolescence Cohort Study which was conducted in 1995-1996. The same researchers from 1995 were able, in 2010, to use the same questionnaires, interviews and clinical examinations in order to conduct the 15 year follow up. In 1995 the cohort was circa. 14 years old, in 2010 the participants were circa. 28-30 years of age.⁵

The results showed that the prevalence at time of testing of contact allergy increased from 15.1% (of those studied) to 20.1% and that reported past or present allergic contact dermatitis increased from 7.2% to 12.9%.⁶

In the 15 years between the first observation and the most recent one, several new cases of contact allergy and allergic contact dermatitis had developed. The contact allergen causing the greatest number of new cases was nickel which the researchers found surprising because in the intervening period the nickel regulations of 1990 would have been fully implemented.

In 2010 the most common sensitisers (found in things like jewellery, sticking plasters, and hair dyes) were nickel sulphate, cobalt chloride, colophony, thimerosal and p-phenylenediamine.⁷ The researchers noted that the drop in prevalence of sensitivity to Fragrance Mix I might be explained by the replacement of old fragrance chemicals by new ones in cosmetic products.

Charlotte Gotthard Mørtz, one of the researchers said “The results suggest that Fragrance mix 1 is now a poor marker for history of eczematous skin reactions to perfumed products, it seems likely that many of the ingredients have now been superseded in cosmetic products by newer ones.”

2.  C. G Mortz, C. Bindslev-Jensen, K. E. Andersen, Department of Dermatology and Allergy Centre, Odense University Hospital, University of Southern Denmark, DK-5000 Odense C, Denmark

3.  Nicholson P J & Llewellyn D (Editors). Occupational contact dermatitis & urticaria.  British Occupational Health Research Foundation. London. 2010. Research Working  Group. Occupational contact dermatitis & urticaria. Systematic review & recommendations. British Occupational Health Research Foundaton. London. 2010. Review date 2015. ISBN 978-0-9564949-0-1

4.  Letter from David Gawkrodger & Ian White to The British Medical Journal in April 2012 “Allergy risk from Royal Mint’s new nickel plated steel coins should be publicly assessed.”  BMJ 2012;344:e2730 (Published 19 April 2012)

5. The Odense Adolescence Cohort Study is a cohort of 1501 unselected 8^th grade schoolchildren established 15 years ago with the aim to follow the course of contact allergy and allergic contact dermatitis from school age to adult life.

6. Contact allergy was defined as a positive patch test using True®Test. Allergic Contact Dermatitis is defined as a the consequence of exposure to a contact allergen exceeding an individual threshold concentration in a contact-sensitised person.  The cross sectional study included questionnaires, interviews and clinical examinations, blood samples for IgE measurement and patch tests.  Phase two was conducted in 1996-7 as a case-control study in selected groups of school children.  Phase three is a 15 year follow up study in the same population and the examination and testing was undertaken by the same investigator who performed the phase one and two studies.

7. Common sensitisers;

Nickel Sulphate (11.8%) – nickel is commonly used in jewellery, metal plating and coinage

Cobalt chloride (2.3%) – used in metal plating

Colophony (2.0%)  is a type of plant resin (it is also sometimes called rosin)  It has a variety of uses including as the glue in sticking plasters, it can also be found in printing ink, varnishes, glue, soap, paper. 

Thimerosal (1.4%) is an organomercury compound used as an anti-fungal and anti-septic

p-phenylenediamine (1.1%) – also known as PPD it is commonly used as a dye and can be found in many hair dyes.