Condition category
Skin and Connective Tissue Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Hidradenitis suppurativa (HS) is a long term, painful skin condition. It involves boils in areas such as the armpit and groin. It affects young adults of working age. HS has a big effect on quality of life due to pain, scarring and release of pus. It also affects sex and relationships. This study will provide vital information to answer questions that were identified as priority areas for research by patients with HS and the doctors and nurses who treat them. The aim is to inform the design of future HS trials and to understand how HS treatments are currently used. This involves five steps:
1. Describe the treatments used around the country (particularly the type of operation, which can vary from centre to centre)
2. See whether patients might consider joining a research study in the future and which treatment(s) they would prefer
3. Define how patients with HS are currently seen within the health service. Learn what influences patients’ and clinicians’ treatment choices
4. Select the best ways of measuring response to treatment (outcome measures)
5. Ask patients and doctors to agree the best design for future HS studies

Who can participate?
Patients aged 18 and over with active HS of any severity that is not adequately controlled by current treatment

What does the study involve?
Patients with HS are invited to join the study as volunteers. By inviting people who are treated by skin doctors and those treated by surgeons, the researchers should receive information about a range of treatments. The volunteers pick from the range of treatments available locally and, for the year after, the researchers record what happens to them. They measure how well the treatment has worked using recommended questionnaires and help to interpret the questionnaire results by checking what changes in score matter to patients and whether the questionnaires are suitable for normal clinical practice. During the study the surgical and laser operations are video recorded to make a training video for future studies.

What are the possible benefits and risks of participating?
Deroofing and laser hair removal, when offered by a recruiting centre, are not usually available for HS in the UK (they are available in several other countries). Participants will also be contributing to standardising outcome measures for future HS trials. Techniques used for surgical procedures are part of standard surgical skills, but all participating surgeons will complete a specialised training package before performing deroofing. Participation in the study will require completion of some additional questionnaires not currently used in routine HS care that will take up additional time during clinic appointments.

Where is the study run from?
1. University Hospital of Wales
2. Hull York Medical School
3. Royal Free Hospital
4. Newcastle Upon Tyne Hospital
5. Broomfield Hospital
6. Guy's & St Thomas Hospitals
7. Barnsley Hospital
8. Stirling Community Hospital
9. Salisbury Hospital
10. Nuffield Orthopaedic Centre

When is the study starting and how long is it expected to run for?
April 2019 to March 2022

Who is funding the study?
Health Technology Assessment Programme (UK)

Who is the main contact?
1. Janine Bates
2. Dr John Ingram

Trial website

Contact information



Primary contact

Ms Janine Bates


Contact details

Centre for Trials Research
College of Biomedical and Life Sciences
Cardiff University
7th Floor
Neuadd Meirionnydd
Heath Park
CF14 4YS
United Kingdom
+44 (0)29 20687616



Additional contact

Dr John Ingram


Contact details

Division of Infection & Immunity
Cardiff University
CF10 4AT
United Kingdom
+44 (0)29 2074 2190

Additional identifiers

EudraCT number number

Protocol/serial number

HTA 17/98/01, SPON 1734-19, IRAS 266172

Study information

Scientific title

Treatment of hidradenitis suppurativa evaluation study (THESEUS)



Study hypothesis

To inform the design of future HS RCTs and to understand how HS treatments are currently used.

Ethics approval

Approved 26/09/2019, Wales Research Ethics Committee 4 Wrexham (Health and Care Research Wales Support Centre,
Castlebridge 4, 15-19 Cowbridge Road East, Cardiff, CF11 9AB, UK; +44 (0)7976 982591;, REC ref: 19/WA/0263

Study design

Prospective cohort study

Primary study design


Secondary study design

Cohort study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet.


Hidradenitis suppurativa


1. Oral doxycycline 200 mg OD for 6 months initially
2. Oral clindamycin and rifampicin both 300 mg BD as a combined course for 10 weeks
3. Laser treatment
4. Deroofing of sinus tracts
5. Conventional surgery (narrow or wide excision, with a range of closure methods)

Participants choose their preferred treatment intervention and have follow ups every three months up to 12 months. They can swap treatment intervention during this time, should they wish to do so.

Intervention type



Drug names

Primary outcome measure

Proportion of participants who are eligible, and hypothetically willing, to use the different treatment options, measured using screening log at baseline

Secondary outcome measures

1. Proportion of participants choosing each of the study interventions, with reasons for their choices, measured using descriptive statistics of each group membership for each intervention at baseline/month 0
2. Proportion of participants who switch treatments during the study follow-up period, with reasons for switch, measured using questionnaires during the study follow-up period
3. Treatment fidelity measured using questionnaire at 3, 6, 9 and 12 months
4. Loss to follow-up rates measured using percentage of consented participants failing to attend appointments over 12 months
5. Efficacy outcome estimates after 6 months’ of follow up to inform outcome measure instruments’ responsiveness (minimum important difference, MID):
5.1. Pain measured using a numeric rating scale at the baseline appointment and then on a daily basis for the first 12 weeks following treatment commencement via mobile telephone text message
5.2. HS-specific quality of life measured using HiSQOL
5.3. Global assessment (average change over time estimation)
5.4. Progression of course (flare frequency) (average change over time estimation)
5.5. Physical signs (average change over time estimation)
5.6. Symptoms (drainage resulting in need for dressings and fatigue) (average change over time estimation)
5.7. Generic quality of life measured using EQ-5D
The researchers will report completeness of each outcome at each timepoint (0, 3, 6, 9 and 12 months)

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Adults at least 18 years old with active HS of any severity
2. Diagnosis confirmed by recruiting clinician with experience of HS care
3. HS not adequately controlled by current treatment
4. At least one of the five study interventions is appropriate for participant’s care

Participant type


Age group




Target number of participants

150 participants

Participant exclusion criteria

1. Unable or unwilling to give informed consent
2. Pregnancy or breastfeeding

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University Hospital of Wales
Heath Park Way
CF14 4XW
United Kingdom

Trial participating centre

Hull York Medical School
University of York John Hughlings Jackson Building University Rd, Heslington
YO10 5DD
United Kingdom

Trial participating centre

Royal Free Hospital
Pond Street
United Kingdom

Trial participating centre

Newcastle Upon Tyne Hospital
Clayton Road
Newcastle Upon Tyne
United Kingdom

Trial participating centre

Broomfield Hospital
Court Road
United Kingdom

Trial participating centre

Guys & St Thomas Hospitals
Great Maze Pond
United Kingdom

Trial participating centre

Barnsley Hospital
Gawber Road
S75 2EP
United Kingdom

Trial participating centre

Stirling Community Hospital
Livilands Gate
United Kingdom

Trial participating centre

Salisbury Hospital
Odstock Road
United Kingdom

Trial participating centre

Nuffield Orthopaedic Centre
Windmill Road Headington
United Kingdom

Sponsor information


Cardiff University

Sponsor details

Research Governance Team
Research and Innovation Services
McKenzie House
7th floor
30-36 Newport Road
United Kingdom
+44 (0)29 2087 9277

Sponsor type




Funder type


Funder name

Health Technology Assessment Programme

Alternative name(s)

NIHR Health Technology Assessment Programme, HTA

Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

The researchers will present the findings from the study at international meetings of doctors and researchers. They will publish them openly in journals, where anybody can see them. The HS Trust patient support group will host links to these publications on its website, including a plain language summary and podcasts.

Results from all studies (cohort, mixed methods and outcome validation studies) will be presented and discussed during the final consensus workshop. This information will be used to inform discussions over preferred study design and priority research questions.

Results from the study will be distilled into a plain language summary that will be written in collaboration with the patient partners. It will be hosted on the HS Trust website and disseminated further via links in social media posts, such as the HS Trust, relevant research networks and journal Twitter feeds.

The researchers will set up a THESEUS study website that will provide information about the study, both during the project and hosting the plain language summary and other outputs afterwards. The website will be designed so that the information is accessible to all stakeholders.

Patient and public involvement
The President of the HS Trust has been a member of the bid team from the beginning and will be part of the group that manages the study. She led the patient survey, using the HS Trust website and social media. The survey, completed by 358 people, helped to shape the study plan. Throughout the THESEUS study, the researchers will interview participants about their study experiences. They will ask about reasons why they might or might not, take part in future studies. A group of people with HS and doctors/nurses/researchers involved in the study will meet in a workshop at the end of the study. This will be used to agree the best designs for future HS research.

IPD sharing statement
The datasets generated and/or analysed during the current study during this study will be included in the subsequent results publication.

Intention to publish date


Participant level data


Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

18/09/2020: The recruitment end date has been changed from 30/09/2020 to 31/03/2021. 29/07/2020: Ethics approval details added. 09/08/2019: Uploaded protocol Version 1.0, 25 July 2019 (not peer reviewed). 01/08/2019: Trial's existence confirmed by the NIHR.