Research and Special Interests

X-ray microanalysis
This technique provides an assessment of the elemental composition of biological specimens by means of x-ray detection in the electron microscope. Previously, little work had been done on its use in skin disease, and the study of its dermatological applications formed the basis for my first major research project at St Thomas’ Hospital and Medical School. My MD Thesis, entitled “Clinical applications of energy-dispersive x-ray microanalysis on hair in dermatology” has been written up for submission to the University of Liverpool.

Three main areas were studied: (i) establishing control values for hair in normal population; (ii) pathological hair disorders; (iii) forensic applications and environmental influences.

Having found disturbances of calcium and potassium in alopecia areata, I now direct and supervise a PhD student who is continuing this project in association with Professor M Kendall, Division of Microanalysis, Department of Biochemistry, St Thomas’ Hospital Medical School. We are investigation further applications of the technique in this disease, in particular analysis of frozen tissues and hair papilla cell cultures, in both scanning and transmission modes. This has involved establishing a cell culture laboratory to study the growth of hair papilla cells. X-ray microanalysis has never before been applied to work on cell cultures.

The methodology and results of several of these studies have been published and presented at several international meetings.

In collaboration with the Anatomy Department at Guy’s Hospital X-ray microanalysis has been used in the investigation of hairs obtained from 18th century corpses in the Crypt of St Brides Church, Fleet Street, London

Hair Disorders
This has been an important are of interest which began in High Wycombe and has been furthered at St Thomas’. My weekly hair clinic provides a regional diagnostic service for hair disorders including scanning electron microscopy and I receive regular referrals from colleagues throughout the country.

Alopecia areata has been a particular subject of investigation. I have established an alopecia areata society (“Hairline”) for the benefit of alopecia areata patients and to promote research into the disease and act as medical adviser to the group and hold quarterly national meetings.

(i) Minoxidil
Topical formulations of minoxidil were developed and controlled trials were performed whilst at High Wycombe. At St Thomas’ a multicentre controlled study to assess the use of 3% minoxidil lotion in the treatment of alopecia totalis was conducted. Subsequent use of 5% concentration established a dose- related response.
Studies on females with androgenetic alopecia have shown a beneficial response to topical minoxidil therapy. The results provided indications for the use of topical minoxidil:
(i) extensive patchy alopecia areata including ophiasis pattern
(ii) male and female androgenetic alopecia of less than 10 years duration in patients who are 20-30 years of age.
The results of the initial minoxidil studies are published and were presented to several meetings including the 1982 American Academy of Dermatology, 1983 summer British Association of Dermatologists and 1984 European Society for Dermatological Research.
Since then new combined treatments have been tried on minoxidil nonresponders. An enhanced response occurs in alopecia areata using 5% minoxidil lotion and a synergistic effect was found by the addition of 0.025% retinoic acid. The results were presented to the 1988 American Academy of Dermatology meeting.
(ii) Other therapeutic studies
– Another vasodilator, Viprostol (Cyanamid: used in treatment of impaired peripheral perfusion) was assessed in a pilot study, and has been found to be ineffective in the treatment of alopecia areata, although of benefit in androgenetic alopecia.
– Diazoxide, a vasodilator which produces hypertrichosis, is to be assessed in topical form in the treatment of alopecia areata and female androgenetic alopecia.
(iii) Influence of HLA Expression on prognosis in alopecia areata. Results showed an increased frequency for HLA A28, B12 and CW7. There was no increased relative risk or frequency for DR3 or DR4. None of these antigens appeared to influence prognosis or response to treatment.
(iv) Studies are in progress to compare the results of phototrichography in androgenetic alopecia to findings on scalp biopsy using both standard tissue sections and Headington’s transverse technique.
(v) Studies are proposed to compare ultrasound visualisation of scalp hair follicles to scalp biopsy in order to assess stages of anagen or telogen and diameter and depth of follicles.
(vi) Laser Doppler Studies. The laser Doppler flow meter has been used to study cutaneous perfusion. Studies were performed to document the influence of topical solutions of Minoxidil (1-5%) on local cutaneous scalp blood flow. Results only showed detectable changes using 5% solution, but the technique did not demonstrate reproducible results even in controls.
(vii) Life events in alopecia areata: a joint psychiatry and alopecia areata clinic is in progress to assess the role of life events in this disorder and to provide group psychotherapy.
(viii) Corticosteroid receptors in alopecia areata. In collaboration with Dr. M Sawaya, Department of Dermatology, University of Miami, USA, and Dr. M Hordinsky, University of Minnesota, corticosteroid receptor sites are being evaluated in scalp biopsies from patients with alopecia areata to compare values in ophiasis pattern with patchy disease of the vertex and crown.

Dermal Papilla Cell Cultures
The dermal papilla is responsible for inducing and maintaining matrix differentiation in hair follicles. In collaboration with the Histopathology Unit, Imperial Cancer Research Fund, London, human dermal papilla cell cultures are being studied morphologically and functionally:

(i) ultrastructural studies of cultured scalp dermal papilla cells and parallel cultures of dermal fibroblasts demonstrated unusual inclusions in the dermal papilla cells. The results of these studies were presented to international scientific meetings and are now published.
(ii) evaluation of retinoic acid cytosol binding sites in dermal papilla cell cultures from normal scalps, androgenetic alopecia and alopecia areata.
(iii) Determination of thymulin production from scalp dermal papilla cell cultures, dermal fibroblast cultures and keratinocyte cultures.
Nail Disorders
This compliments the interest in hair. Since 1984 I attended Dr. P.D. Samman’s Nail Clinic at St John’s Hospital for Diseases of the Skin, and I have now inherited this long-established research clinic since Dr. Samman’s retirement five years ago.
Studies now in progress include:
(i) Yellow Nail Syndrome — investigation of digital and peripheral lymphatic circulation in yellow nail syndrome, in association with Dr. Peter Mortimer at St. George’s Hospital. Abnormal lymphatic function using lymphoscintigraphy was demonstrated in these patients. Results were presented to the British Association of Dermatologists (1990) and the American Academy of Dermatology (1990)
(ii) Childhood Onychomycosis — children with dermatophyte infections of the nails are being investigated in association with Dr. Yvonne Clayton and Professor Rod Hay at St. John’s Hospital. Results have shown an increased incidence with atopy and in families with adults who have onychomycosis.
(iii) X-ray microanalysis — having established the principle elemental analysis of hair it is now proposed to extend this electron microscopy technique to nail disorders.
(iv) Corticosteroid iontophoresis of digits in the treatment of trachyonychia, lichen planus and psoriasis of the nails.
The nail clinic also provided a regional diagnostic service with nail biopsies performed at St. Thomas’ Hospital. In collaboration with the Medical Illustration Department at St. Thomas’, a poster exhibit documenting the work of clinic was awarded the Royal Pharmaceutical Society Trophy at the 1991 Medicine and Life Science Meeting of the Royal Photographic Society of Great Britain.

(a) Giant Congenital Melanocytic Naevi
Giant hairy naevi in children pose not only cosmetic problems but also therapeutic difficulties. In conjunction with the Department of Plastic Surgery at St. Thomas’ Hospital and Dr. David Atherton at the Hospitals for Sick Children, Great Ormond Street, the histopathology of the naevi and the treatment using shaving and dermabrasion was studied. The following results were established:
(i) Melanocytes already extend as deep as the subcutis and fascia at birth and do not migrate in the neonatal period.
(ii) There is no correlation between clinical appearance and histopathological pattern or depth of naevus.
(iii) There is no change in depth of naevus with age.
(iv) Shaving technique does not remove all the melanocytes and should only be considered a cosmetic procedure. Depth of pigment may be used to predict the cosmetic response to shaving.
(v) Long term complications of shaving include hyperpigmentation, depigmentation, hypertrophic scarring and the development of pseudomelanoma.
A joint clinic with Plastic Surgery is now in progress to assess the long term efficiency of shaving and its influence on malignant change on these naevi.
The results of these studies have been presented at the British Association of Dermatologists 1987,VII International Congress of Dermatological Surgery 1987, British Society of Dermatology 1986, American Society of Dermatopathology 1987. This work was awarded the Bristol Cup Prize at the British Association of Dermatologists Summer Meeting, 1987.
(b) Darier’s Disease
In conjunction with Professor Irene Leigh at the Royal London Hospital and Dr Sue Burge at the Slade Hospital, Oxford, we investigated the pathogenesis of Darier’s Disease by immuno-histochemical staining using monoclonal antibodies to human cytokeratins. The following results were established;
(i) Delay in expression of suprabasal skin specific keratins in lesions compared to normal perilesional skin.
(ii) There was no true premature keratinisation.
(iii) Etretinate treatment does not influence keratin expression in involved or uninvolved skin.
(iv) Expression of type VII collagen was normal.
The results of this study were presented to the 1986 summer British Association of Dermatologists meeting and are now published.

(c ) Amyloidosis
The response of lichen amyloidosis to treatment with 13-cis retinoic acid (Etretinate) has been assessed. The initial results appear to suggest a reduction in amyloid deposits associated with a clinical improvement, which was limited by the development of xeroderma and hyperlipidaemia. The results of this study are now published. Further studies to assess the effect of cyclophosphamide in lichen amyloidosis are in progress.

Auto Immune Disease
(a)Autoimmune cutaneous disease and the thymus gland
I am part of a multidisciplinary study into the normal function of the thymus and its disarrangement in disease, collaborating with the Departments of Endocrinology, Obstetrics, Immunology, Biochemistry and Physiology at St. Thomas’ Hospital and Medical School and the Department of Immunology at the Royal Postgraduate Medical School. The thymus is now regarded as the prime organ in development that teaches the body’s cells to recognise self and disturbances in this process may result in autoimmune disease.

Thymic function is being assessed by use of a new radioimmunoassay which is capable of measuring plasma thymulin or FTS (factor thymique serique). Initial results have shown a diurnal variation of thymulin in normal controls and low levels in patients with alopecia areata. A clear decline in plasma thymulin level was seen across the disease spectrum from patchy hair loss to universalis hair loss, i.e. the more extensive the hair loss the lower the hormone level, some patients with established alopecia totalis or universalis having nondetectable thymulin values. Known thymulin “stimulants” including zinc and growth hormone are now being monitored by plasma thymulin measurements in the treatment of alopecia areata.

Assessment of immune function using thymulin levels and peripheral T lymphocyte subset counts is also being used in the human growth hormone trials.

The studies are now being expanded to assess thymic function in patients with lupus erythematosus, lichen sclerosus et atrphicus, linear IgA disease, vitiligo, pemphigus, pemphigus gestationis, pemphigoid, Down’s syndrome and hyperprolactinaemia.

In association with the Department of Immunology at St. Thomas’ Hospital and the Institute of Cancer Research at the Royal Marsden Hospital, I established a research clinic to investigate the incidence of autoimmune disease in patients with sarcoidosis and the families and to speculate on an autoimmune basis for the pathogenesis of sarcoidosis.

The results, suggesting common major histocompatibilty complex genes in sarcoidosis and autoimmunity, have been published and presented to the British Association of Dermatologists meetings.

Arachidonic Acid Metabolism and Lipoxygenase Inhibition
Whilst at Wycombe General Hospital, I investigated the mechanism of benoxaprofen phototoxicity. In addition, open and controlled studies were conducted to assess the effect of benoxaprofen on several dermatoses (acne vulgaris, psoriasis, persistent palmo-plantar pustulosis, aphthous ulceration and nodular prurigo), finding a dramatic effect on pustular disorders and a beneficial response in psoriasis. The results of these studies are published and were presented at the 1983 summer British Association of Dermatologists.
Argon Laser and Infrared Coagulation in Portwine Stains

I have gained expertise in the use of both the argon laser and the infrared coagulator. Since both of these methods have been suggested as treatment for “portwine” capillary haemangiomas, I conducted a study to compare the use of both these methods of therapy in the same lesions. Results showed that although infrared coagulation is cheaper and less time consuming than argon laser, it produces more inflammatory response, more scarring and is less sensitive to control.

The results of this study were presented at the 1988 British Association of Dermatologists meeting.

Growth Hormone Studies
In collaboration with the Unit of Endocrinology and Diabetes at St. Thomas’ Hospital, London, I am evaluating hair growth cycle and nail growth rate in two controlled trials using human growth hormone (Norditropin) in (i) growth hormone deficient adults and in (ii) elderly patients awaiting elective total hip replacement. Skin biopsies will also be examined in the hip replacement group to assess skin thickness, elastin, collagen and IgF-1 messenger RNA.

Polycystic Ovarian Syndrome
In collaboration with the Units of Endocrinology and Chemical Pathology, St.Thomas’ Hospital, we are investigating lipid metabolism in this disorder and the effect of treatment with cyproterone acetate on serum lipid profiles.

An open study has been conducted to assess the use of this novel compound (shark’s bile extract in superficial inflammatory acne vulgaris). This data was presented to the Australasian College of Dermatologists this year.

Get in Touch

“I just want to say thank you to Dr David Fenton (and his team!) for the exceptional care and kindness shown to my son over the last 18 months. His support also to an anxious mother has been tremendous”

JT, London

“It is always so lovely to see Dr Fenton and I want to thank him for the support, encouragement and kindness he always shows myself and my husband. We really appreciate the time and wise words that he so kindly gave us.”

ZD, Essex

“I’d like to say thank you to Dr Fenton for being such an amazing doctor for the last 24 years and all his help in treating my alopecia.”

KM, Surrey

“I am so grateful to Dr Fenton’s gentle ministering and I am so glad to say that with his help my hair has totally grown back now. Although not life-threatening, alopecia was disheartening and I was so pleased to be able to come and see Dr Fenton and be treated so successfully. It is amazing the quackery and suggestions that are out there! I am very lucky.”

JD, Kent