Contact allergy and exposure patterns to thiurams and carbamates in consecutive patients

Glove-Related Allergic Contact Dermatitis

Hand dermatitis is a common condition with a lifetime prevalence of 20%. Glove allergic contact dermatitis (ACD) is a very important dermatitis affecting health care workers, hairdressers, cleaning personnel, kitchen workers, craftsmen, construction workers, laboratory workers, and homemakers. Occupationally related cases may be severe and can result in significant disability. Glove ACD is most commonly due to exposure to rubber accelerators, which are compounds that are added to rubber during production to increase strength and durability. Given the known allergic potential of these compounds, glove manufacturing companies have reformulated gloves leading to the introduction of new rubber allergens. In this review, we will discuss risk factors for glove ACD, both common and uncommon allergens in gloves, common contact allergens that permeate gloves, and patch testing to help uncover the inciting allergen(s).

[Contact allergies in the German workforce : Data of the IVDK network from 2003-2013]

BACKGROUND

In Germany, occupational skin diseases rank first in the occupational skin disease statistics for many years. Especially, occupationally acquired contact allergies as well as multi-sensitization are the most important predictors for a poor prognosis and persistent eczema.

OBJECTIVES

To update the spectrum and sensitization frequencies of most frequent allergens from the standard series in Germany in patients with occupationally acquired type IV sensitizations in general and within different occupational groups.

METHODS

Data of all employed patients (age range: 16-68 years, n = 14234) patch tested between 2003 and 2013 in the German Departments of the Information Network of Departments of Dermatology (IVDK) and diagnosed occupationally acquired contact dermatitis after patch testing were analyzed. The control group was composed of all other patients (n = 31706) within the same time frame, in which occupationally acquired allergic contact dermatitis was negated explicitly.

RESULTS

The prevalence Ratio (PR; indicating risk) was significantly increased for: Thiuram-mix (PR 5.63 95 %CI 4.97-6.4), zinkdiethyldithiocarbamate (PR 6.22 95 %CI 4.76-8.22), mercaptobenzothiazole (MBT) (PR 3.88 95 %CI 3.09-4.89), mercapto-mix without MBT (PR 3.23 95 %CI 2.59-4.03), N-isopropyl-N'-phenyl-p-phenylene diamine (IPPD) (PR 2.3195 %CI 1.87-2.86), epoxy resin (PR 2.82 95 %CI 2.45-3.25), chloromethylisothiazolinone/methylisothiazolinone (MCI/MI) (PR 2.19 95 %CI 1.97-2.42) and compositae mix II (PR 2.05 95 %CI 1.45-2.89). They were the predominant occupational allergens and were at least associated with a doubled risk (PR ≥ 2.0) for acquiring occupationally allergic contact dermatitis. The highest risk increase was identified in employees in the health services, in agriculture, metal industry, food and service industry as well as building trades

CONCLUSIONS

A limited number of occupationally relevant allergens cause the majority of sensitizations in the workforce, if standard series allergens are concerned. Data analysis of national and international contact allergy data bases provide valuable information on sensitization rates and profiles in skin risk occupations to implement targeted prevention strategies. To diagnose occupational allergic contact dermatitis in individual cases additional testing of occupation related patch test series as well as patients' own products is commonly inevitable.

Occupational rubber glove allergy: results of the Information Network of Departments of Dermatology (IVDK), 1995-2001

About 21% of the patients with occupational contact dermatitis registered in the Information Network of Departments of Dermatology (IVDK) in the years 1995-2001 were patch tested due to suspected rubber glove allergy. We analysed reaction frequencies to thiurams, dithiocarbamates, mercaptobenzothiazole (MBT) and its derivatives, thioureas, and 1,3-diphenylguanidine (1,3-DPG). Thiurams were by far the most frequent rubber allergens in these patients (16.2% positive reactions, age- and sex-standardized), and the reaction frequency showed a decline from 20.9% in 1997 to 12.8% in 2000. However, this trend was not statistically significant, and was followed by an increase to 16.5% in 2001. All other rubber allergens showed no time trend at all. Although, according to manufacturers' information, the use of dithiocarbamates and MBT derivatives in rubber glove production increased in recent years, these allergens elicited positive reactions in only about 3% of the patients tested, and showed no increasing trend. Thioureas and 1,3-DPG are not widely used in rubber glove production, and play only a minor role in rubber glove contact allergy. Most of the positive reactions to 1,3-DPG are probably false-positive, irritant reactions.

Assessment of contact allergen cross-reactivity by retesting

At former allergic contact dermatitis reaction sites retesting causes augmented hyper-reactivity, characterized by an accelerated onset within a few hours. This expression of 'local skin memory' has been ascribed to locally persisting allergen-specific effector/memory T cells. To verify this hypothesis, we investigated whether accelerated retest reactivity also occurs with cross-reactive allergens. Guinea pigs were immunized with either or both 2,4-dinitrochlorobenzene (DNCB) and 2-hydroxyethyl methacrylate (HEMA), and primary skin tests to these and cross-reactive methacrylic compounds were performed 12-21 days later. Subsequently, new skin tests were conducted 3 weeks later both at the former test ('retest') and contralateral, non-pretreated test ('control') sites, and skin test readings started 2 h later. Retest reactivity was evaluated by comparing retest and contralateral control reactions. Both contact sensitizers, HEMA and DNCB, induced strong retest reactivity, peaking at 4-6 h. Fully allergen-specific retest reactivity was observed when primary skin tests had been postponed until 21 days after immunization, most probably reflecting loss of accumulation of irrelevant allergen-primed T cells at that time. As hypothesized, retesting with various methacrylate congeners at primary HEMA, but not DNCB, skin test sites showed early hyperreactivity strengths in line with those observed earlier in conventional cross-reactivity studies. These results, therefore, support the view that local skin memory exhibits allergen specificity through residual allergen-primed T cells. Because the retesting procedure is readily applicable in clinical practice, it provides a tool not only for confirmation of doubtful contact allergic skin reactions, but also for distinguishing between true cross-reactivity and coincident multiple sensitization in man.

Protective gloves in Swedish dentistry: use and side-effects

BACKGROUND

During the 1980s routine wearing of gloves in dentistry was recommended by health authorities in several countries. However, prolonged glove use is associated with side-effects of irritant and allergic origin.

OBJECTIVES

To investigate the extent of glove use and self-reported glove intolerance reactions among Swedish dentists, and to examine how far IgE-mediated allergy to natural rubber latex (NRL) occurs in subjects who report rapid itching when in contact with protective gloves.

SUBJECTS/METHODS

A postal questionnaire was answered by 3083 of 3500 licensed dentists, a response rate of 88%. Of the dentists who reported rapidly occurring itching of the hands from gloves, 131 of 170 attended a clinical examination including a skin prick test (SPT) and a serological examination (RAST) for IgE-mediated allergy.

RESULTS

Seventy-three per cent of the dentists reported daily glove use of more than 2 h, 48% more than 6 h a day, and 6% reported no use. NRL gloves were used most frequently (P < 0.001) and were the main material that elicited symptoms (P < 0.001). Female dentists reported more frequent glove use than males, as did young dentists (P < 0.001) compared with older ones. Females also preferred vinyl gloves. Glove intolerance reactions were reported by 723 (23%) dentists, [females 28%, males 21% (P < 0.001)] and were more common in younger dentists. Of the 417 dentists with reported hand eczema during the previous year, 54% reported glove intolerance, compared with 20% of the dentists without hand eczema (P < 0.001). A logistic regression analysis including hand eczema, age, sex and atopy showed that all these factors contributed significantly to the risk of glove intolerance, and that hand eczema was a stronger factor than atopy. In 15 of 131 (11%) dentists examined for reported glove-related itch, latex allergy was verified by SPT and/or RAST. Glove-related conjunctivitis, rhinitis and asthma, in contrast to skin symptoms, showed a significant association with IgE-mediated allergy to NRL.

CONCLUSIONS

Swedish dentists show good compliance with the recommendations for routine glove use. Intolerance reactions are frequently reported, especially by dentists with hand eczema, which emphasizes the need for preventive skin care programmes. Glove-related symptoms from mucous membranes showed a higher association with IgE-mediated allergy to NRL than reported itching of the skin, a fact that should be considered when composing screening questionnaires for NRL sensitization

National rates and regional differences in sensitization to allergens of the standard series. Population-adjusted frequencies of sensitization (PAFS) in 40,000 patients from a multicenter study (IVDK)

Sensitization rates to contact allergens vary between centers and are influenced by sex and age. Eliminating the latter 2 factors by standardization of data by age and sex, the present analysis addresses possible differences between centers remaining after elimination of these confounders, and analyzes other factors which might influence rates, e.g., the MOAHL index. Overall standardized rates were well within the range reported in previous studies and may be regarded as representing the rates of the "patch test population" in Central Europe (e.g., nickel sulfate 12.9%, fragrance mix 10.5%, balsam of Peru 7.3%, thimerosal 5.6%). For this analysis, data of those departments which contributed more than 2000 patients, or of those with extreme proportions concerning sex, age and occupational cases were selected. Patients from these 10 departments differed considerably with regard to the items of the MOAHL index and with regard to standardized rates. The items of the MOAHL index proved to be suitable for describing different patch test populations and for explaining some differences between centers. Only 'atopic dermatitis' seems to have little influence on (standardized) rates. Face dermatitis is not yet represented in the MOAHL index, but should be included, together with age > 40 years, in an extended index (acronym: MOAHLFA). Regional allergen exposure (with striking differences between East Germany, West Germany and, to a lesser extent, Austria) seems to have a great influence on the sensitization pattern observed in a department. In addition, sociological factors may influence sensitization rates, which is exemplified by high rates of nickel allergy in a socially defined subgroup. Future studies should focus on these factors, as well as on factors concerning patch test practices and quality control.