Washing Powders Not Cause Of Eczema, Study Confirms

Main Category: Eczema / Psoriasis
Article Date: 23 May 2008 - 0:00 PDT

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Healthcare professionals should not attribute skin reactions to bio washing powders, a new study will warn. According to research due to be released in the British Journal of Dermatology, bio washing detergents are no more harmful to people with eczema than their non-bio counterparts, despite a popular belief to the contrary.

Biological (bio) laundry detergents differ from non-biological (non-bio) products in that they contain enzymes, which were first added to assist stain removal. In addition, their efficiency at low temperatures and their biodegradability both offer environmental benefits.

However, for years it has been suggested that bio laundry detergents can trigger skin reactions, and that they should be avoided by people with eczema, as the enzymes might worsen the disorder. Interestingly, this line of thought is unique to the UK.

This suspicion is thought to have arisen from cases where proteolytic enzymes, the type most commonly used, produced skin irritation, mainly when used occupationally by workers producing a detergent enzyme. Links to eczema when used in normal circumstances have, however, remained unclear and anecdotal.

A team of researchers from Nottingham and London therefore conducted a review of evidence, looking at both the actual exposures through use of the product, and at exaggerated levels that would not normally occur through normal use.

Dr Sarah Wakelin, Dermatologist at St Mary's Hospital in London and one of the researchers, said: "In the UK, the background awareness of questions about allergy and irritation has translated into concern among some consumers and consumer groups that enzyme-containing detergents may be related to a variety of consumer skin complaints. Anecdotally at least, a similar view appears to be held by a variety of healthcare professionals.

"In this review, we looked at the facts, asking whether there is evidence that the hazards identified for enzymes translate into any risk for consumer health."

The researchers concluded that the possible irritant and allergic reactions that could be caused by enzyme raw materials do not translate into a risk of skin reactions when used in washing powders.

Dr Wakelin explained: "What we have found is that ultimately, the balance of all the evidence is that enzymes in laundry detergents are not a cause of either skin irritation or skin allergy. Investigations of numerous individuals with skin complaints attributed to laundry products demonstrate convincingly that enzymes were not responsible. Indeed, enzyme-containing laundry products have an extensive history of safe use. Thus, the supposed adverse effects of enzymes on skin seem to be a consequence of a mythology."

The evidence:

In this latest study, the researchers reviewed a wide range of evidence on the subject. This includes a 1969 study in Ohio, US, in which 739 subjects took part in tests involving a range of main wash and pre-soak detergents, with and without proteolytic enzymes. With the tests employing exaggerated use conditions, there was no significant increase in skin irritation in any of the hand or arm immersion assays that could be attributed to the presence of enzyme. Products were then used normally in a total of 5943 subjects and the hands examined by a dermatologist. No differences were observed between the enzyme and control treatments.

The same scientists then conducted a study of 360 babies, in which their nappies were washed in the test and experimental products and the nappies worn. There was no difference in the incidence or severity of nappy rash between groups of infants wearing nappies laundered in the products with or without enzymes.

In 1975, German researchers specifically tested the enzymes used in detergents, rather than the detergents themselves. These tests were carried out not only on normal skin but also on irritated or damaged skin. The enzyme solutions caused no irritation or other damage to the normal or slightly lesioned skin, even in response to close contact lasting several days. Irritation only occurred when the sin was damaged to an extent that allowed the enzymes to penetrate the lower layers of skin, and in such cases the enzyme concentrations far exceeded those used in commercial detergents. The researchers therefore concluded that any effects caused by laundry detergents are due not to the enzyme content of these detergents, but to other factors.

Several studies have also looked at the effects of product residues left on clothes after washing. These studies used fabrics containing detergent residues and a variety of exaggerated exposure tests. In all the studies, no evidence that residues in the fabrics caused irritancy was obtained.

Dr Wakelin said: "In terms of allergy, the evidence is consistent with what we know of the physiology of skin allergy.

"Substances must penetrate the outer skin barrier to reach the lower layers and do so in a sufficient quantity to activate the immune system in such a manner as to lead to an allergic response. By virtue of their size, enzymes are unlikely to penetrate the skin to any great degree. Also, enzymes in laundry products are encapsulated in robust, inert barrier. This means that actual skin exposure will be extremely low.

"Thus, the only occasions when there is likely to be some degree of exposure is either to the wash solution (when the enzyme encapsulate has dissolved) or from any enzyme residues on fabrics. As shown by various studies, contact with wash solutions does not lead either to irritation or to allergy, and residues on fabrics are also trivially low and do not give rise to any skin effects."

Dr Colin Holden, President of the British Association of Dermatologists said: "This study highlights that flare-ups of eczema should not just be written of as caused by washing powder. This serves as a reminder to medical professionals that an expert dermatologist should explore all the other potential causes, as bio detergents may well not be the culprit."

Notes

1. If using this information, please ensure you mention that the study is being released in the British Journal of Dermatology, the official publication of the British Association of Dermatologists.

2. For more information please contact: Nina Goad, British Association of Dermatologists, Communications Manager, Phone: 0207 391 6355, Email: nina@bad.org.uk, Website: http://www.bad.org.uk

3. Articles in the BJD can be viewed online here.
Study details: "Enzymes, detergents and skin: facts and fantasies"
D.A. Basketter *†, J.S.C. English ‡, S.H. Wakelin § and I.R. White †
British Journal of Dermatology June 2008, doi:10.1111/j.1365-2133.2008.08561.x, pp1177-1181

*DABMEB Consultancy, Sharnbrook, Beds, U.K.†St John's Institute of Dermatology, St Thomas' Hospital, London, U.K., J.S.C. English‡‡Department of Dermatology, Nottingham University Hospital, Nottingham, U.K., S.H. Wakelin§§Department of Dermatology, St Mary's Hospital, London, U.K. and I.R. White††St John's Institute of Dermatology, St Thomas' Hospital, London, U.K.

The British Association of Dermatologists is the central association of practising UK dermatologists. Our aim is to continually improve the treatment and understanding of skin disease.

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