I graduated in medicine at St Thomas’ Hospital, University of London (now part of King’s College, London) and undertook my general/internal medicine training in the north of England and in Australia.Having gained my MRCP I trained in dermatology at the Institute of Dermatology (St John’s) in London, and in Aberdeen and Edinburgh. I spent some time out of my clinical training to complete a research MD degree.  Having completed my dermatology training, I gained a scholarship from the University of Edinburgh, and spent three years in post-doctoral research training in the laboratories of Prof Victoria Kolb-Bachofen, Heinrich-Heine Universität, Dusseldorf, and of Dr Tim Billiar, University of Pittsburgh, USA.I was recruited from America to the post of Senior Lecturer, and latterly Reader in Dermatology and Associate Principal Investigator at the Centre for Inflammation Research, University of Edinburgh.My time is divided between clinical duties, where I am an honorary NHS Consultant Dermatologist with a particular interest in medical dermatology and eczema, and the University where I have an active research group, and also a significant teaching commitment as Programme Director of the M.Med.Sci degree. 

Ultraviolet radiation and the skin

In 1996 I made the first description of nitric oxide (NO) production on the skin surface.  NO at the time was known to dilate blood vessels and thus help regulate blood pressure- work for which the discoverers received the Nobel Prize for Medicine or Physiology in 1998- but it was also involved in control of a number of other functions.  Initially working in Aberdeen and Edinburgh and then at Heinrich-Heine University, Dusseldorf and the University of Pittsburgh I set out to uncover the role of this naturally produced NO in the skin.  Following the standard dermatological dogma of the time I spent my time in Germany and America looking at the effects of NO on keratinocyte (skin cell) survival after sun exposure. Although I was able to show effects of NOS derived NO in inhibiting apoptosis in cell culture and murine models, I was unable to replicate this in man.  Developing my work in Edinburgh on healthy volunteers, I was able to show that human skin contains large stores of nitrogen oxides (NOx) and that these are photo-reduced by UV radiation releasing NO to the circulation, with systemic effects, in particular lowering of BP.  This work is summarised in a TED talk

Work from my group and with a number of international collaborators is now finding a growing number of physiological and homeostatic processes that are dependent on this UV-skin NO mobilisation pathway.  Partly spurred on by the discovery of this mechanism, the risk-benefit ratio for population sunlight exposure is being reconsidered in Europe, Australia and the USA.  It is becoming clear that Vitamin D synthesis is not the only sun dependent homeostatic mechanism, and may in fact only account for a small part of health  benefits attributed to sun exposure. 

Current research activity:

• I am now studying the effects of UV on systemic immunity. With current PhD student Jiayue Gu we are measuring the effects of UV on immune regulation in man using single cell RNA sequencing.
• In collaboration with Professor Chris Dibben we have been studying the link between sunlight and all cause mortality at population level in the UK using data from the UK Biobank.  We show that increased sunlight exposure correlates with reduced all-cause, cardiovascular and cancer mortality  Higher ultraviolet light exposure is associated with lower mortality: an analysis of data from the UK Biobank cohort study | medRxiv
• In collaboration with colleagues from the Renal Research Institute, we have performed a cross-sectional study of UV and BP in >340,000 dialysis patients at >2,000 locations to differentiate effects of wavelength, temperature and skin type on BP response to UV. We are now working on identifying the action spectrum of the BP lowering function of sunlight.
• I have been collaborating with Dr Shelley Gorman in Perth, Australia, who has identified a UV-skin NO mechanism limiting development of obesity and metabolic syndrome. 

Eczema

My main clinical research interest is in Eczema and I also run the specialist adult eczema clinic for NHS Lothian in conjunction with Dr Claire Leitch. With Claire and others we have previously identified immunological functions of the filaggrin protein, which is usually deficient in eczema patients. I am currently co-supervising two PhD students looking at different aspects of eczema pathophysiology. 

Current research activity

• My collaborator Dr Chengcan Yao has identified a new PGE2-IL22 pathway  which we then showed to be involved in subtypes of eczema.  PhD student Fiona Cunningham is working on this. 
• Collaborator Dr  Donald Davidson has identified an antiprotease function of human beta defensin which limits barrier function damage created by Staph aureus exotoxins.   PhD student Jenny Shelley is continuing this work
• I am principle investigator in Edinburgh for the EUROSTAD eczema registry study

Cutaneous leishmaniasis and Ethiopia

I have been teaching, training and examining dermatology residents in Ethiopia for the last decade, with annual visits and extended stays of 2 and 3 months in 2011 and 2017.  I have recently started collaborating with a team led by Dr Pascale Kropf  of Imperial College, studying the immunology of cutaneous leishmaniasis in Ethiopia, and particularly trying to identify why some patients have self limiting CL, while others progress to destructive, and often fatal Diffuse Cutaneous and Mucosal Leishmaniasis.

TED talk

MB BS 1987

MRCP 1990

GMC Specialist Register (Dermatology) 1998

MD  2000

FRCP(Ed) 2006

One minute ( and a bit!) summary of my UV research