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The Softened Water for Eczema prevention trial (SOFTER) is an outcome assessor-blinded pilot randomised controlled trial of an ion-exchange water softener for the prevention of atopic eczema in newborn babies. The trial is led by Dr Carsten Flohr, Consultant Paediatric Dermatologist at St John’s Institute of Dermatology, Guy’s and St Thomas’ NHS Foundation Trust.

SOFTER is a study designed to see if the use of water softeners can help prevent eczema.

Eczema is a common skin condition that causes inflamed and itchy skin. It currently has no cure, only symptom relieving treatments. Eczema is more common in infants living in hard water areas. These are places that allow water to pick up more of the naturally occurring minerals as it passes through the ground. Our aim is to see if softening the water that is used to bathe babies that are at a higher risk of developing eczema can help to prevent this from happening.

Trials Design

Who is taking part in the study?

We are looking for expectant mothers who will be having their babies at either St Thomas’ Hospital or Kingston Hospital. Participants will be required to be living in a hard water area (we can check this using your postcode) and have an increased likelihood of developing eczema. This is characterised by either of the biological parents, or any sibling of the baby having a history of or currently suffering from eczema, asthma or hayfever.

Participation is completely voluntary and your decision to take part or not does not impact on the care you and your baby receive.

Participants are free to withdraw from the study at any stage, without giving a reason. We will arrange the removal of your water softener.


What does participation involve?

Once you have had time to read through the information given to you, our team will give you a call to answer any further questions and arrange to meet with you at your antenatal appointment at around 30-34 weeks into your pregnancy. To take part in the SOFTER trial you will need to be able to have a water softener fitted in your home, usually under the kitchen sink. If you are renting the property this will require permission from your landlord, we can give you a letter template to help with this. As water softeners replace calcium and magnesium in the water with sodium from common salt, a separate supply of drinking water to your kitchen is necessary. Where possible this will through the existing kitchen tap, otherwise this may require a separate tap to be fitted to your sink. A plumber will schedule a visit to your home and check suitability for fitting the water softener, you will then be randomised to receive either normal water or softened water. We are unable to tell you in advance if you will have the water softener fitted for the trial as this is decided by a computer and we are ‘blinded’ to this decision for the duration of the trial. Those that do not receive a water softener for the trial will have the opportunity to have one installed afterwards for a 6 month try-out. All the plumbing work for the installation and removal of the water softeners is done by a trained plumber and at no cost to the participants.

Once your baby is born we would come to see you both while you’re still in hospital and carry out some non-invasive skin tests on your baby (see below for a description of each). We would also invite you to bring your baby back for 3 more visits at the age of 4 weeks, 3 months and 6 months so that we can repeat the skin tests. At monthly intervals between these visits we also ask that you complete an online questionnaire about you baby’s skin and general health (we can remind you when it gets close to the time). Those that have water softeners for the trial will be asked to send water samples to Harvey Water Softeners each week, using prepaid envelopes, to check it is working properly. Finally, at the end of the study, you may be invited to take part in an optional short interview of around 30 minutes to ask about your experience of taking part. This can be done either by phone or in person at St Thomas’ Hospital/Kingston Hospital.


What are the benefits of being involved?

Aside from contributing towards the research we are doing into preventing eczema, all participants will be given the chance to purchase the water softeners for a discounted price of £399. In addition, all those completing the final survey will receive a £20 Amazon voucher.


What are the skin tests?

We use several different pieces of equipment to take measurements and samples of your baby’s skin, however these are all relatively non-invasive and cause no harm. The exact measurements offered vary depending on the study site. We use an instrument that rests on the skin to look at the amount of water in your baby’s skin, and another that measures the pH and compounds on the surface, such as soap residues or naturally occurring oils. Small sticky-tape discs allow us to take a few microscopic samples of the skin for us to study the immune system in a process that is akin to carefully peeling off sellotape. On the first visit we swab the arm and nose of each baby to examine the bacteria on the skin surface, and we take a saliva sample to identify genetic markers for eczema.


What happens to the samples, data and confidential information collected?

All samples and data are labelled using a code, so no identifiable data is passed on. The samples are analysed at King’s College London and at other universities in Europe and the US. After analysis, all samples are disposed of. Data is held in accordance with the Data Protection Act 1998. At the end of the study the data is stored in a secure archiving facility until your child reaches the age of 25, when it is destroyed as per the legal requirements for studies involving children.

Your contact details are kept on file to allow us to reach you during the study and are disclosed only with our commercial partner, Harvey Water Softeners Ltd., for installation, maintenance and removal (where necessary) of the water softener.

All other information about you and your baby that we take as part of the study has your name, address and any other identifiable details removed. No one will be able to identify you from anything we record. All computers used are password protected and only the members of our team that are directly involved in the study have access to this information. With your permission, we will inform your baby’s GP of their involvement in the study.


Are there any risks, side effects or drawbacks?

Softening the water your baby bathes in poses no added risks to those from washing with regular water.

The samples taken require a very small amount of pressure to the skin surface, and so these too provide no extra possible cause for harm.

The study does require you to attend the hospital after your baby’s birth for a couple of appointments with us that may last between 1 to 2 hours. We will reimburse reasonable travel costs.

If you have any concerns about the study please ask to speak to one of the researchers so that we can help. If you are not satisfied and wish to complain formally, this can be done through the Guy’s and St Thomas’ Patient Advice and Liaison Service (PALS) on 020 7188 8801, or in person at St Thomas’ main entrance, where they are based. At Kingston Hospital, PALS can be contacted on 020 8934 3993, The PALS team are located at the junction of the link corridor and Bernard Meade Wing.


What happens to the results of the study?

As this is a pilot study, we will use the information gained from this study to plan a larger scale trial to look at the effects of water softeners in eczema prevention.

The results will also be published at conferences and in professional journals.

We will also send our study findings to all participants.


How is this study approved and funded?

All research within the NHS has to be reviewed by a Research Ethics Committee. This study was reviewed and given it a favourable opinion by the North West – Liverpool East Research Ethics Committee (Ref: 17/NW/0661).

The National Institute for Health Research (NIHR), the Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and Harvey Water Softeners Ltd. provide the funding for this study.

Trials coordinators: Nikeeta Gurung & Alexander Phillips.

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Our Partners


National Institute for Health Research (NIHR)

Guy's and St Thomas'  logo

Guy's and St Thomas' NHS Foundation Trust

Logo of the St John's Institute of Dermatology

St John's Institute of Dermatology

University of Dundee

University of Dundee

Project status: Completed

Principal Investigator


Contact us

Feel free to contact us if you have any questions.


  • Unit for Population-Based Research, St John's Institute of Dermatology, St Thomas Hospital
  • London, SE17EH