I saw a patient recently who came to clinic with a possible disease entity that was quite prevalent in Europe and the UK from the summer of 2006 for a period of time. Believe it or not, it was called ‘sofa dermatitis.’ Fortunately (for his sofa, at least), he didn’t have sofa dermatitis.
What is sofa dermatitis?
It is not actually a dermatitis to all sofas. It is, in fact, a reaction to an allergen in leather furniture materials. The epidemic which started in Finland and the UK in the autumn of 2006 was to new sofas and chairs impregnated with a chemical called dimethyl fumarate (DMF).
What is dimethyl fumarate?
It is a chemical which was used for its ability to prevent the growth of mould in large leather items. Leather goods usually don’t have a problem with mould growth but they do when transported between different climates where confined spaces and humid environments can lead to the build up of moisture.
DMF is packaged as a white crystalline powder into little sachets that are either placed under the leather covering of the sofa or attached to the wooden frame. The crystalline powder evaporates over time but in doing so, also gets absorbed into the leather materials covering the sofa.
[http://www.dermnetnz.org/topics/allergy-to-dimethyl-fumarate/]
Is it in all leather sofas and chairs?
No thank goodness. All the cases were of reactions to chairs and sofas made in China with one report stating that all the cases were linked to the same furniture factory in China. Leather and fabric sofas were implicated.
[Susitaival P, Winhoven SM, Williams J et al. An outbreak of furniture related dermatitis (‘sofa dermatitis’) in Finland and the UK: history and clinical cases. J Eur Acad Dermatol Venereol 2010;24:486-9.]
Unfortunately, certain leather shoes made in China were also culpable and an epidemic to leather shoes was also reported at the time in Spain and parts of France.
So what does dimethyl fumarate do?
It was declared the Contact Allergen of the Year for 2011 by the American Contact Dermatitis Society. The reason for this is because it is a potent allergenic sensitizer and it use in consumer products has since been banned by the EU since January 2009. Saying that, the USA and Australasia do not have any regulations in place regarding DMF.
[http://www.dermnetnz.org/topics/allergy-to-dimethyl-fumarate/]
[Susitaival P, Winhoven SM, Williams J et al. An outbreak of furniture related dermatitis (‘sofa dermatitis’) in Finland and the UK: history and clinical cases. J Eur Acad Dermatol Venereol 2010;24:486-9.]
What do you see?
Patients reported a severe eczema or dermatitis that was quite resistant to treatment. It involved areas of skin in contact with the sofa, so the back, buttocks, backs of legs and arms were the areas generally affected.
Severe eczema affecting a large part of the back
Involvement of the back of the thigh and calf too.
Further studies by contact allergy specialists showed that it was the repeated exposure to DMF to large areas of skin combined with its strong sensitizing potential that resulted in the severe reactions seen. Some people were even hospitalized, such was the severity of their reactions.
[Basketter DA, White IR, Burleson FG et al. Dimethylfumarate: potency prediction and clinical experience. Contact Dermatitis 2013;68:269-72.]
How do I know if I have ‘sofa dermatitis’?
Well firstly, you will have a new sofa and will also have developed a severe eczema in all the places that are in contact with the sofa. If you have a reaction on your feet and you have recently purchased some new shoes, it will be in all the places in contact with your new shoes.
To definitively know whether you are allergic to DMF, patch testing will need to be done by a dermatologist who specializes in cutaneous allergy and performs patch tests.
And the treatment?
This would involve treatment of the eczema and removal of the offending item.
Yours sincerely,
Sandy
Dr Sandy Flann, Consultant dermatologist.
