Excipient and Dose per Unit Area Affect Sensitivity When Patch Testing With Gold Sodium Thiosulfate.

BACKGROUND: Dose/area and reading paradigms for gold patch testing are controversial and not standardized worldwide. OBJECTIVES: The aims of this study were to determine the optimum patch test dose of gold sodium thiosulfate (GST) in a hydrogel (HYD) and to establish GST HYD safety/efficacy and further characterize normal morphology and time course of GST reactions. METHODS: Twenty gold-allergic patients were patch tested with a dilution series of GST HYD and with GST 2% petrolatum (pet). Furthermore, this previously determined optimal dose was compared with GST 0.5% pet in 19 known-allergic and 216 consecutive subjects. RESULTS: The optimal GST HYD dose was 0.075 mg/cm, not statistically different from GST 2% pet (P = 0.4795). Gold sodium thiosulfate HYD outperformed GST 0.5% pet in both known-allergic subjects (79% vs 63%, P = 0.2482) and consecutive subjects (30% vs 9%, P < 0.0001). Late reactions were common in consecutive patients with both HYD and pet. Significantly more persistent reactions were associated with GST HYD than with GST 0.5% pet. CONCLUSIONS: Gold sodium thiosulfate HYD 0.075 mg/cm is the optimal dose for diagnosis of gold contact allergy with GST. Gold sodium thiosulfate 0.5% pet yielded false-negatives in some patients, suggesting inadequate dose per centimeter squared. Late reads are normal, expected, and necessary for diagnosis of gold contact allergy in this cohort.

Low-level mercury exposure and peripheral nerve function.

BACKGROUND: Mercury is known to be neurotoxic at high levels. There have been few studies of potential peripheral neurotoxicity among persons with exposure to elemental mercury at or near background levels. OBJECTIVES: The present study sought to examine the association between urinary mercury concentration and peripheral nerve function as assessed by sensory nerve conduction studies in a large group of dental professionals. METHODS: From 1997 through 2006 urine mercury measurements and sensory nerve conduction of the median and ulnar nerves in the dominant hand were performed, and questionnaires were completed, on the same day in a convenience sample of dental professionals who attended annual conventions of the American Dental Association. Linear regression models, including repeated measures models, were used to assess the association of urine mercury with measured nerve function. RESULTS: 3594 observations from 2656 subjects were available for analyses. Urine mercury levels in our study population were higher than, but substantially overlap with, the general population. The only stable significant positive association involved median (not ulnar) sensory peak latency, and only for the model that was based on initial observations and exclusion of subjects with imputed BMI. The present study found no significant association between median or ulnar amplitudes and urine mercury concentration. CONCLUSIONS: At levels of urine mercury that overlap with the general population we found no consistent effect of urine mercury concentration on objectively measured sensory nerve function.

Frequency of contact allergens in pediatric patients with atopic dermatitis.

OBJECTIVE: The authors compared the prevalence of positive patch tests in atopic pediatric patients versus nonatopic controls and sought to determine if statistically significant allergen prevalence differences existed between the two groups. DESIGN: Retrospective chart review. SETTING: Rady Children's Hospital, San Diego, California. PARTICIPANTS: Patients with suspected allergic contact dermatitis between the ages of 6 and 18 years who had been enrolled in the Pediatric Research Equity Act Thin-layer Rapid Use Epicutaneous Test trial. MEASUREMENTS: Statistical analysis used Z-scores to compare associations between positive reactions in atopic versus nonatopic patients and the prevalence of individual chemicals in either group. RESULTS: RESULTS showed that at least one allergen reaction was noted in 78 percent (n=79) of the patients, 89 percent (n=48) in atopic patients, and 66 percent (n= 31) in the nonatopic patients (Z-score 2.78). Eczema area and severity index scores ranged from 0 to 41.75. Eczema area and severity index scores greater than 10 correlated with a higher probability of more than three positive patch tests (Z-score [-]3.28). Statistically significant differences were also observed between atopic and nonatopic patients in regards to contact allergens, with 20 percent (n=11) of atopic patients exhibiting positive patch tests to Myroxylon pereirae and 19 percent (n=10) of those with atopic dermatitis having reactions to fragrance mix. CONCLUSION: The authors concur with prior studies that performing systematic patch testing is indicated in children with moderate-to-severe atopic dermatitis, given the high rate of contact allergy in the atopic group, especially those with eczema area and severity index scores greater than 10. Furthermore, prevention through exposure avoidance to the most frequent contact allergens, especially fragrances in patients with atopic dermatitis, is recommended.

Safety and efficacy evaluation of TRUE TEST panels 1.1, 2.1, and 3.1 in children and adolescents.

BACKGROUND: The Thin-layer Rapid Use Epicutaneous (TRUE) Test has approval for adults. OBJECTIVE: To evaluate the efficacy and safety of TRUE Test panels 1.1, 2.1, and 3.1 in children and adolescents suspected of having allergic contact dermatitis (ACD). METHODS: An open-label prospective study was performed, analyzing 102 consecutive patients aged 6 to 18 years referred for suspected ACD, between December 2008 and October 2009. Patch tests were applied for 48 hours, and evaluations of skin reactions were conducted at days 3 and 7, with a follow-up visit 3 weeks after the initial applications. RESULTS: The mean age of all enrolled subjects was 11.6 years, and subjects included 52% females and 48% males. Positive reactions noted in more than 10% of the children were to nickel sulfate (29.7%), p-tert-butylphenol formaldehyde resin (16.8%), wool alcohols (15.8%), fragrance mix (12.9%), and cobalt dichloride (12.9%). Of the 101 subjects, 77 (76.2%) tested positive to one or more of the 28 allergens. No meaningful differences were observed in the frequency or severity of adverse events; reports of burning and stinging following patch removal; or the frequency, intensity, or symptoms of persistent reactions when evaluated by age, sex, or race. CONCLUSION: Patch testing is efficacious and safe in the pediatric population.

Latex allergy and filaggrin null mutations.

OBJECTIVES: Natural rubber latex (NRL) contains over 200 proteins of which 13 have been identified as allergens and the cause of type I latex allergy. Health care workers share a high occupational risk for developing latex allergy. Filaggrin null mutations increase the risk of type I sensitizations to aeroallergens and it is possible that filaggrin null mutations also increase the risk of latex allergy. The aim of this paper was to examine the association between filaggrin null mutations and type I latex allergy. METHODS: Twenty latex allergic and 24 non-latex allergic dentists and dental assistants, occupationally exposed to latex, were genotyped for filaggrin null mutations R501X and 2282del4. Latex allergy was determined by a positive reaction or a historical positive reaction to a skin prick test with NRL. RESULTS: 41 individuals were successfully genotyped. Three individuals were filaggrin mutation carriers. One (2.4%) was a 2282del4 heterozygote and two (4.9%) were R501X heterozygote. No homozygote or compound heterozygote carriers were detected. No association between filaggrin null mutations and type I latex allergy was found (p=0.24). Patients with type I latex allergy more often reported contact dermatitis. CONCLUSIONS: This is the first study to examine a highly plausible association between filaggrin null mutations and type I latex allergy. The study subjects were occupationally exposed to latex but no association between latex allergy and filaggrin mutations were detected. Sensitization to latex in the cases in this study may not have occurred through direct skin contact but through the respiratory organs via latex proteins that are absorbed in glove powder and aerosolized.

Prevalence of upper extremity symptoms and disorders among dental and dental hygiene students.

CONTEXT: Upper extremity musculoskeletal disorders are common among dental professionals. The natural history of these disorders is not well-understood. These disorders are more common in older workers, but the prevalence among younger workers has not been well-studied. OBJECTIVE: The objective of this study was to determine if dental/dental hygiene students had a similar prevalence of upper extremity musculoskeletal disorders compared to age-matched clerical workers. We hypothesize students will have a lower prevalence of upper extremity musculoskeletal disorders compared to clerical workers. DESIGN: This was a cross-sectional design. SETTING: Dental and dental hygiene students from three schools were compared to clerical workers from three locations (an insurance company and two data processing plants). SUBJECTS: There were 343 dental and dental hygiene students and 164 age-matched clerical workers. MAIN OUTCOME MEASURES: Regional discomfort was the primary outcome. The secondary health outcomes were diagnoses of carpal tunnel syndrome and upper extremity tendinitis. RESULTS: Clerical workers had a higher prevalence of hand symptoms (62 percent vs. 20 percent), elbow symptoms (34 percent vs. 6 percent) and shoulder/neck symptoms (48 percent vs. 16 percent) and a higher prevalence of carpal tunnel syndrome (2.5 percent vs. .6 percent) and upper extremity tendinitis (12 percent vs. 5 percent). The clerical workers were more obese, smoked more, exercised less frequently, and had lower educational levels and less control of their work environment. CONCLUSIONS: Dental and dental hygiene students have a very low prevalence of upper extremity musculoskeletal disorders. A longitudinal study is necessary to evaluate ergonomic and personal risk factors.

Cross-reactivity between gutta-percha and natural rubber latex: assumptions vs. reality.

BACKGROUND: Immunological cross-reactivity between gutta-percha and natural rubber latex, or NRL, has not been demonstrated clearly despite recent concerns and several suspected cases reported in the literature. METHODS: The authors analyzed aqueous extracts of commercial gutta-percha points and raw gutta-percha samples for cross-reactivity to NRL by radioallergosorbent test, or RAST, inhibition; immunoblot inhibition; direct enzyme-linked immunosorbent assay, or ELISA; and ELISA inhibition using sera from NRL-allergic people as the source of anti-NRL immunoglobulin E, or IgE, antibodies. To confirm in vitro results, the authors conducted skin prick testing, or SPT, on a patient with type I NRL allergy using aqueous extracts from raw gutta-percha, ammoniated gutta-percha and gutta-percha points. RESULTS: Aqueous extracts from commercial gutta-percha points did not cross-react to NRL in RAST inhibition or immunoblot inhibition, ELISA or ELISA inhibition assays. However, three of 13 sera from subjects with type I NRL allergy exhibited IgE binding to raw gutta-percha extracts in direct ELISA. Moreover, in ELISA inhibition, the binding of IgE to raw gutta-percha extracts was inhibited in a dose-dependent manner by raw NRL and vice versa. SPT results from a subject with type I NRL allergy were positive for NRL and raw gutta-percha extracts but negative for gutta-percha point extracts. CONCLUSIONS: The authors found no detectable cross-reactivity between NRL and commercial gutta-percha points. However, their ELISA and SPT results demonstrated that some allergenic cross-reactivity exists between raw gutta-percha and raw NRL. CLINICAL IMPLICATIONS: Gutta-percha alone is not likely to induce symptoms in patients with type I NRL allergy. However, other materials used in obturating root canals may be irritating and potentially allergenic in patients with pre-existing allergies.

Prevalence of carpal tunnel syndrome and upper extremity tendinitis among dental hygienists.

PURPOSE: This study was undertaken to determine the prevalence of carpal tunnel syndrome (CTS) and upper extremity (UE) tendinitis among dental hygienists. METHODS: In a cross-sectional study dental hygienists (n = 305) were screened using sensory nerve conduction, a focused physical examination of the UE, and a symptom questionnaire. CTS was diagnosed if the subject had slowing of the median nerve at the wrist and symptoms of numbness, tingling of pain in the median distribution. Localized tendinitis of the UE was diagnosed if the subject had focal symptoms and associated findings on physical examination. RESULTS: Three percent of the participating dental hygienists were diagnosed with CTS. Thirteen were diagnosed with shoulder tendinitis, while 6% had a tendinitis of the elbow and 7% had tendinitis of the hand or wrist. Twenty-eight percent had a diagnosis of some UE tendinitis or CTS. CONCLUSIONS: The prevalence of hand and finger symptoms in the dominant hand among dental hygienists in this study was high, but the prevalence for CTS was nearly the same as the general population. There was a high rate of UE tendinitis noted within this population.