Iain S. Foulds

Photopatch testing of 1155 patients: results of the U.K. multicentre photopatch study group

Background  Photoallergic contact dermatitis can be difficult to diagnose if not appropriately investigated. Currently, the most common U.K. photoallergens appear to be sunscreen chemicals. The investigation of choice is photopatch testing (PPT), which is probably underused. In part, this is due to differences in methodology and results interpretation.

High-performance liquid chromatography of unmodified rosin and its applications in contact dermatology

Rosin is a well recognised skin sensitiser and is also amongst the most common causes of occupational asthma. Due to its complex chemical composition, it is difficult to isolate its many components and this has hindered progress in the identification of the specific respiratory and contact allergens it contains. This paper reports the application of high-performance liquid chromatography and other analytical techniques to the isolation and identification of contact allergens in complex mixtures such as rosin. HPLC methods were developed in order to isolate as many rosin components as possible and these were then patch tested on rosin sensitive individuals. The structure of the most dermatologically active component was then determined using mass spectrometry, nuclear magnetic resonance and infrared techniques. An HPLC method has also been developed which will enable the identification of rosin in commercial products, providing a valuable tool for determining the cause of rosin contact allergy. Furthermore, mass spectral data for the common abieitic-type resin acids are compiled which were used to confirm the identification of the HPLC resin acid peaks and have not been reported previously.

Orofacial granulomatosis worsened by chocolate: results of patch testing to ingredients of Cadbury's chocolate

We report a 26-year-old man with orofacial granulomatosis, characterized by granulomatous swelling of his lips and oral ulceration, confirmed on biopsy. After only partial response to oral steroids, he was referred for patch testing. He volunteered that his symptoms worsened after eating chocolate. Initial patch testing to Cadbury’s drinking chocolate (usually consumed by our staff) showed a positive result at 48 h. We subsequently patch tested him to the ingredients of Cadbury’s chocolate supplied by the company, including: cocoa liquor, cocoa butter, soya-based lecithin (emulsifier), rape-based lecithin (emulsifier) and dark chocolate. He was clearly positive to cocoa liquor, the complex natural product extracted from cocoa beans, establishing that cocoa itself was responsible for his chocolate intolerance (Fig. 1). Flare-up of our patient’s condition during patch testing confirmed the clinical relevance of our findings (Fig. 2).

Oxidation of resin acids in colophony (rosin) and its implications for patch testing

Commercial preparations of colophony (rosin) used for patch testing are made from unmodified rosin in pet. and may be stored for some considerable time before being used. This would be satisfactory if the composition and dermatological activity of the preparations were both reproducible and stable, but investigations by the authors have shown that the resin acids undergo progressive and substantial oxidation and that the dermatological activity of the preparations increases significantly with time. This may be a cause of inconsistent patch test results unless the composition can be stabilized. Gas liquid chromatography (GLC) analysis of a raw rosin sample and its commercial patch test preparation has shown that they both contained the same resin acids, but the concentration of the abietic type resin acids was found to be lower in the patch test preparations. The degradation of resin acids is due to their atmospheric oxidation, which may occur during the preparation and storage of the commercial rosin patch test preparation. The susceptibility of individual resin acids to atmospheric oxidation was demonstrated by analysing a sample of raw Portuguese gum rosin, which was then left exposed to air and light. Most of the resin acids were found to undergo oxidation at a rate which gradually diminished. More importantly, it is presumed that the concentration of oxidized resin acids increased correspondingly, and these have been shown to be more dermatologically active than the unoxidised resin acids. The rate of decrease of resin acid concentration was found to be in the following order: neoabietic > levopimaric and palustric > abietic > dehydroabetic acid. The pimaric type resin acids were found to be relatively inert to atmospheric oxidation when compared with the abietic type resin acids. Patch testing with the resulting partly oxidized Portuguese rosin produced positive reactions at a 35% higher frequency than the raw Portuguese rosin. The study demonstrates that the allergic potential of unmodified rosin may increase with exposure to air and light. It is therefore recommended that rosin preparations are analysed routinely as part of a quality control programme, which will enable better validation and comparison of patch test results from different dermatological centres. Since the oxidized resin acids are the main allergens in unmodified rosin, it is important that the concentration of the oxidized resin acids is kept high as well as constant in commercial patch test preparations.

Dermatological hazards in the electronics industry

The advent of the electronics age has resulted in the rapid growth and increasing importance of the electronics industry on a global scale. The main industrial processes are Fabrication of semiconductor wafers, printed circuit boards, the assembly of semiconductor devices, printed circuit boards and the final electronic products. The process carry the risk of various work hazards, among them dermatological hazards, These include exposure to irritants and allergens during common operations such as soldering, cleaning operations, materials handling, procedures For control of static electricity and low humidity in the work environment. Even the use of protective clothing may be associated with the risk of dermatitis, In spite of the numerous dermatological hazards, the risk for work‐related skin disorders among electronics workers appears to be low when compared to other industries. However, the vast size of the electronics workforce will contribute to large numbers of workers with occupational dermatoses. Occupational health personnel responsible for factories in the electronics industry should therefore be aware of the cutaneous hazards present, and how these may lead to work‐related dermatoses.

Identification of contact allergens in unmodified rosin using a combination of patch testing and analytical chemistry techniques

Summary In order lo investigate the contact allergens in the unmodified colophony (rosin) used in routine patch testing, preparative chromatographic techniques were used to separate its components which were then patch tested on colophony‐sensitive individuals. The chemical structure of the dermatologically active components was elucidated using mass spectrometry, nuclear magnetic resonance and infra‐red techniques. The study shows that oxidized resin acids are stronger sensitizers than the resin acids themselves, the most potent contact allergen being 7‐oxydehydroahietic acid (purity 92%). At naturally occurring concentrations (relative to abietic acid) all unoxidized resin acids were found to play an insignificant part, individually, in colophony dermatitis, except abietic acid (purity 99%), which was found to be a weak but important allergen. The commercial Trolab abietic acid preparation (unknown purity) was found to be dermatologically more active than purified abietic acid.

A multicentre review of the hairdressing allergens tested in the UK

Allergens used for patch testing in the hairdressing series vary between dermatology centres in the UK. The aim of our study is to ascertain the hairdressing allergens currently in use and their test results in several dermatology centres in the UK. Data were obtained from databases in 9 dermatology departments. The allergens with positive results and current/past relevance were included in a new hairdressing series based on collective experience, for wider use and further evaluation.

Patch testing for corticosteroid allergy with low and high concentrations of tixocortol pivalate and budesonide

M. M. U. Chowdhury, B. N. Statham1, J. E. Sansom2, I. S. Foulds3, J. S. C. English4, P. Podmore5, J. Bourke6, D. Orton7 and A. D. Ormerod8 Departments of Dermatology, 1University Hospital of Wales, Cardiff, Singleton Hospital, Swansea, 2Bristol Royal Infirmary, 3Birmingham Skin Centre, 4Queens Medical Centre, Nottingham, UK, 5Alnace Skin Hospital, Londonderry, Northern Ireland, 6South Infirmary Victoria Hospital, Cork, Ireland, 7Amersham Hospital, Bucks, 8Aberdeen Royal Infirmary, Scotland, UK

Loss of lanolin patch-test positivity

Summary Thirty‐seven patients who had shown a relevant positive patch‐test response to lanolin within the previous 5 years were retested. Only 41% demonstrated persistence of the positive patch test to lanolin. Analysis according to age, sex, atopic status, interval between patch testings, strength of the original response and the number of concurrent reactions, were not associated with the persistence of the lanolin response.

Imidazole cross-sensitivity to sulconazole.

Ammals were not sensitized w1th the 0.3% aq. and 1% aq. lm!dazolidinyl urea concentratiOns. One gumea p1g per test group was sens1tized m the experIments w1th 5% aq., 25% aq. and 50% aq. mduction concentrations of imidazolidinyl urea. The 10 control ammals were negative. 4 positive reactiOns were observed after a 2nd challenge w1th I% aq. formaldehyde. 2 of the 4 gumea p1gs had previOusly also reacted to lm!dazolidinyl urea. 2 of 3 lm!dazolidinyl urea sensitized ammals reacted to formaldehyde. All 10 controls were negative (Table I).