Cutaneous and systemic sequelae from exposure to 2-vinylpyridine

We present the case of an employee of a chemical production factory who became sensitized to 2-vinylpyridine despite wearing full protective polyvinyl chloride clothing. He developed severe dermatitis at the site of contact, secondary eczematization over the flexures and periungual areas, as well as marked systemic upset. Pyridines are known sensitizers although this reaction pattern has not previously been described.

Severe adverse cutaneous reaction to insulin due to cresol sensitivity

We present the case of an 80-year-old lady known to be sensitive to chlorocresol (4-chloro-3-methyl phenol) who developed severe erythrodermic exfoliative dermatitis with atypical features 2 weeks after commencing subcutaneous insulin. All medications except insulin were stopped, without major improvement. It was noted that the insulin contained m-cresol (m-methyl phenol) so a parabens-based insulin was substituted. There was a significant improvement in her clinical condition within 72 hr. Further patch and intradermal testing to the insulin and m-cresol was planned, but she developed a nosocomial infection and died. We hypothesize that the adverse cutaneous reaction was a systemic manifestation of cresol sensitivity, given the rapid clinical resolution on changing insulins and the previously demonstrated sensitivity to chlorocresol, particularly as cross-reactivity between different low molecular weight methyl phenols is documented. Local injection site reactions and systemic side-effects including nausea, diarrhoea and vomiting have previously been reported with cresol-containing insulins, although to our knowledge, this is the first reported case of a severe cutaneous reaction. It is important to be aware of m-cresol as a potential allergen, as it is contained in most commercially available insulins.

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.

OBJECTIVES

To conduct PPT using a group of sunscreen chemicals, defined indications and a standardized methodology including interpretation and relevance of reactions in patients attending for investigation at 17 centres across the U.K., Ireland and the Netherlands.

METHODS

Patients (n = 1155) who fulfilled the inclusion criteria were investigated with PPT using sunscreen chemicals in addition to suspected topical products. Readings were taken at 24, 48 and 72 h following standardized ultraviolet A irradiation (5 J cm(-2)). The clinical relevance of any reaction was recorded.

RESULTS

Of the 1155, 130 had allergic reactions (11.3%). Of these, 51 had photoallergy (PA) (4.4%), 64 had contact allergy (CA) (5.5%), and 15 patients had combined PA and CA (1.3%). Multiple PA was seen in some. The most common photoallergen was benzophenone-3 (27 reactions; 21%). Most reactions (60%) were clinically relevant. The most common indication for testing in patients found to have PA was a history of reacting to a sunscreen (41%). The other 59% had an exposed-site dermatitis/skin problem or a photodermatosis. Some centres (n = 8) performed readings after the standard 48-h reading, and an extra 32 PA and 22 CA reactions were detected, which were not evident at 48 h. A new photoallergen (octyl triazone) was detected in two patients.

CONCLUSIONS

Sunscreen PA and CA are probably equally uncommon. Most reactions, of both reaction types, were relevant clinically. A large proportion of patients (59%) found to have PA was unaware of reacting to a sunscreen chemical, suggesting that PA should be considered as an explanation in any exposed-site dermatitis. Although this study focused on reactions at 48 h postirradiation, readings performed up to 96 h, while inconvenient, add value by detecting additional relevant responses. A previously unknown photoallergen was found, highlighting the need for awareness of novel photoallergens in the marketplace. A standardized PPT method not only encourages more use of this investigation, but also facilitates comparison of results between centres and so will improve our understanding of PA.

Sensitisation to natural rubber latex: an epidemiological study of workers exposed during tapping and glove manufacture in Thailand

OBJECTIVES

To estimate the prevalence of sensitisation to natural rubber latex in latex tappers and latex glove factory workers, and to relate this to airborne exposure to latex.

METHODS

Five hundred workers employed in three latex glove factories, 314 tappers, and 144 college students (control group) were studied. The workers in the glove factories were classified into three exposure groups; high, moderate, and low. Personal exposures to natural rubber latex aeroallergens were measured by immunoassay. Symptom questionnaires and skin prick tests with latex allergens (Stallergènes 1:200 w/v) and other common environmental allergens were performed. The criterion for positivity was a wheal reaction at least 3 mm in diameter greater than that to a diluent control.

RESULTS

The geometric mean (GM) concentration of latex in air was 15.4 microg/m(3) for those employed in glove stripping, glove inspections, and packing of powdered gloves. The moderate exposure glove manufacturing group and the tappers had GM concentrations of 2.3 and 2.4 microg/m(3) respectively, compared with United Kingdom users of latex powdered gloves,who had GM concentrations of 0.5 microg/m(3). The prevalence of sensitisation to latex in the tappers and latex glove factory workers was 1.3% and 1.7% respectively. No positive cases were found among the college students. Workers who showed a positive skin prick test to latex were more likely to be atopic. Work related respiratory and dermatological symptoms were found in about 20% of each population studied, but were not related to the presence of positive latex prick tests.

CONCLUSIONS

This study suggests that in the Thai latex industries, latex sensitisation is rare despite high concentrations of airborne exposure and is less prevalent than in the healthcare sector in Europe where skin exposure is greater.

The reproducibility of patch tests

There is conflicting evidence regarding the reproducibility of patch testing. Discordant results have been reported in up to 44% of cases. The clinical relevance of these discordant patch tests has not been previously assessed. We studied 383 consecutive patients receiving simultaneous duplicate patch testing on opposite sides of the upper back with 10 allergens from the European standard series. Completely discordant patch tests-a negative test on one side with a positive test on the opposite side-were recorded in 30 (8%) patients. Two patients had discordant tests to two of the allergens; 28 had discordant reactions to one allergen. Completely discordant tests were recorded for nickel in 10 (3%) patients, balsam of Peru in two (0.5%), thiomersal in one (0.3%), cobalt in four (1%), paraphenylenediamine in three (0.8%), fragrance mix in two (0.5%), formaldehyde in four (1%), potassium dichromate in two (0.5%), lanolin in three (0.8%) and Kathon CG in one (0.3%). Of those patients with completely discordant patch tests, the allergen was deemed to be a true positive in 11 (3% of total) cases and of possible relevance in a further three. The allergen was felt to be relevant to the presenting complaint in seven (2% of total) patients.

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.

Allergy to phosphorus sesquisulfide: 0.5% pet. is a more appropriate concentration for patch testing

Patch testing was performed with phosphorus sesquisulfide P4S3 in 2 groups containing equal numbers of patients using different concentrations (0.5% P4S3 in pet. and 1% P4S3 in pet., the usual suggested test concentration as recommended by the International Contact Dermatitis Research Group). We found that there was a statistically significant increase in the number of clinically irrelevant irritant reactions in the group tested with the concentration (chi 2 = 16, p < 0.0004). We recommend that patch testing with phosphorous sesquisulfide should be at a reduced concentration of 0.5% pet.

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.

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

In order to 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-oxydehydroabietic 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.

Allergic potential of neutrals in unmodified colophony, and a method for their separation from resin acids

An ion-exchange fractionation technique for the separation of total resin acid and neutral fractions of unmodified colophony is described. The allergic potential of these fractions was assessed by patch testing colophony-sensitive individuals, and this showed that both the neutral components and the resin acids play an important role in colophony sensitization. A greater frequency of positive reactions was obtained using the 60% colophony patch test preparation compared with the currently recommended 20% colophony preparation. Furthermore, some individuals were found to produce positive reactions to only the neutral components in colophony. We suggest that the use of a colophony patch test battery comprising resin acids, neutrals, oxidized resin acid and some colophony derivatives, will facilitate detection of colophony-sensitive individuals. Moreover, we consider that this will help to provide a better estimate of the prevalence of colophony dermatitis, which is currently underestimated.

Colophony--uses, health effects, airborne measurement and analysis

Colophony (rosin) is a widespread natural product obtained form species of the pine family Pinaceae. One of the most important uses of unmodified rosin is in electronic solder fluxes while the main areas of use of chemically modified rosin are paper sizing, adhesives, paints, varnishes, printing inks and plasticisers. Colophony is well recognized as a skin sensitizer and is also the third highest cause of occupational asthma. However, the specific allergens involved particularly in occupational asthma have not been comprehensively assessed or identified. This paper reviews method of colophony production, its uses and health effects and discusses the important issue of its chemical analysis and the choice of a suitable marker for monitoring colphony fume.

Allergic contact dermatitis from resin hardeners during the manufacture of thermosetting coating paints

5 production operators from 2 factories manufacturing thermosetting coating paint developed work-related skin disorders within 12 months of the introduction of a new powdered paint product. All 5 workers were found to have allergic contact dermatitis from 2 epoxy resin hardeners, both of which were commercial preparations of triglycidyl isocyanurate (TGIC). 2 of the workers had concomitant sensitization to epoxy resin in the standard series and several of the epoxy resin preparations at the workplace. TGIC has been reported as a contact sensitizer both in persons producing the chemical and among end-users of TGIC-containing products. These 5 reported cases document allergic contact dermatitis from commercial TGIC among exposed workers during an intermediate process of powdered paint manufacture. The possibility of substituting this epoxy resin hardener with less sensitizing alternatives should be explored.

Fiberglass dermatitis from printed circuit boards

Seven cases of fiberglass dermatitis among production operators in the electronics industry are reported. This was due to the repeated daily handling of printed circuit boards (PRCBs). The predominant complaint of the workers was itch of the lateral aspects of the fingers and finger webs. In six workers, unroofed vesicles, pinhead areas of postinflammatory hyperpigmentation, and excoriation marks were noted at these sites. Skin stripping of the affected sites confirmed the presence of fiberglass spicules in all cases. The glass fibers had diameters of 11-16 microns. Patch testing of six of the workers with the European Standard series of allergens revealed no relevant work-related contact sensitizers. Microscopic examination of the free edges and scrapings from the PRCBs showed glass fibers of similar fiber length and diameter to those found in the workers' skin. Fiberglass can be used as a reinforcement filling material in some types of PRCBs. Free edges of such PRCBs have easily detached fiberglass spicules. Workers in frequent contact with these PRCBs can have a fiberglass-induced irritant dermatitis. Preventive measures could include the use of PRCBs with less free fiberglass at its edges, vacuuming of the newly cut boards, use of dusting powder, protective devices and emollients, and improved personal hygiene of the workers.

Loss of lanolin patch-test positivity

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.

Basal-cell carcinoma complicating a port-wine stain

A rare radio-resistant basal-cell carcinoma is described which presented as a recently enlarged non-ulcerated nodule on a port-wine stain. The literature on basal-cell carcinoma occurring on a port-wine stain is reviewed, and the aetiological significance of thorium-X, sun-exposure and vascular changes in the development of malignancy on this type of haemangioma is discussed.

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.