The investigators aim to recruit 311 participants to this study from three UK Dermatology departments. The investigators will invite people with suspected skin cancers whose lesions have a broken surface (also known as ulcerated) who will undergo surgery.

This study is being carried out because it is possible that patients with skin cancers with ulceration might be at greater risk of developing a wound infection after surgery. The aim of this study is to determine how many people with ulcerated skin cancers develop an infection of the wound after it has been surgically removed.

People with ulcerated skin cancers who will have surgery will be invited to participate in the study. If they agree, a member of the research team will explain the study and consent them to participate in the study. At the time of surgery, information will be collected about the participant, skin tumour and procedure. The participant will be given standardised advice regarding wound care and further care will be as per each centre's 'normal clinical care'. If participants are diagnosed with a wound infection then they will asked to take a 'wound selfie' and share the photo with the research team. The research team will contact the participant via a postal questionnaire which will be sent four weeks after the procedure to determine whether they had any concerns about post-operative infection and whether any action was taken.

Additionally, all participants at the University Hospital of Wales will have a surface swab taken from their ulcerated skin cancer and these will be analysed in the Public Health Wales laboratory at the University of Wales, Cardiff. The aim of this aspect of the study is to identify the most common bacteria in ulcerated tumours.

Clinicians in the dermatology departments will identify eligible participants at the time of initial consultation. An information leaflet will be provided and details of the participants who are interested in participating will be forwarded to the research team to check eligibility prior to the procedure. Prior to the procedure relevant clinical information will be recorded in the Case Report Form (CRF) including demographic data, tumour site, tumour size, size of tumoural ulceration and type of wound closure. Histopathological data will be collected on tumour type when it is reported. Participants and clinicians will be asked whether they would agree for the patients to be randomised to no antibiotics, topical treatment eg. InadineTM dressings, a short course of antibiotics or a longer course of antibiotics in a future RCT. Following the procedure, information about whether oral antibiotics were prescribed will be recorded on a standardized CRF. All participants will be provided with the same information leaflet detailing standard post-operative advice and further care will be as per each centre's 'standard clinical care' which will also be recorded.

If participants are diagnosed with SSI they will be asked to take a photo of their wound on a camera phone and then to share the photo with the Cardiff University Centre for Trials Research (CTR) via email. Reeves et al. have described this practice as a 'wound selfie' and report that the term is readily understood. If participants are not able to take of photo of their wound then they will be invited to attend the department to have a photograph taken by medical photography. All participants will be sent a questionnaire by the research team four weeks following their procedure to enquire specifically whether the participant was diagnosed and treated for wound infection. These data will be collected by Cardiff University CTR who will co-ordinate the study.

Additionally, all participants at University Hospital of Wales will have a surface swab taken from their ulcerated skin tumour and these will be analysed in the Public Health Wales laboratory at the University of Wales, Cardiff. The aim of this aspect of the study is to identify the most common organisms that colonise ulcerated tumours. Previous studies have commented on growth from ulcerated tumours, however it is not clear if this was conducted in a research laboratory setting. This will help to guide antibiotic choice in a future randomized controlled trial.

Inclusion Criteria:

1) at least 18 years old

Exclusion Criteria:

1. Evidence of wound infection at the time of the procedure
2. Skin tumour removal undertaken curettage or Mohs micrographic surgery
3. People without the capacity to consent for the study
4. People who are on systemic immunosuppressive treatment
5. People who are already taking oral antibiotics

People undergoing surgical excision of ulcerated skin cancer of any type at any body site in the dermatology departments at the University Hospital of Wales Cardiff; Churchill Hospital, Oxford and Queen Elizabeth Hospital, Birmingham.

4 weeks