Systemic nickel allergy: oral desensitization and possible role of cytokines interleukins 2 and 10

Cross-Reactivity of Intraoral Allergic Contact Mucositis in the Nickel-Sensitized Ear Model of Metal Allergy

Cross-reactivity of metal allergies can make metal allergy treatment complicated because the background of immune response in cross-reactions remains unknown. In clinical settings, cross-reactivity among several metals has been suspected. However, the precise mechanism of immune response in cross-reactivity is unclear. Two sensitizations with nickel, palladium, and chromium plus lipopolysaccharide solution into the postauricular skin were followed by a single nickel, palladium, and chromium challenge of the oral mucosa to generate the intraoral metal contact allergy mouse model. Results showed that the infiltrating T cells in nickel-sensitized, palladium- or chromium-challenged mice expressed CD8+ cells, cytotoxic granules, and inflammation-related cytokines. Thus, nickel ear sensitization can cause cross-reactive intraoral metal allergy.

Oral tolerance as antigen-specific immunotherapy

Oral tolerance is a physiological phenomenon described more than a century ago as a suppressive immune response to antigens that gain access to the body by the oral route. It is a robust and long-lasting event with local and systemic effects in which the generation of mucosally induced regulatory T cells (iTreg) plays an essential role. The idea of using oral tolerance to inhibit autoimmune and allergic diseases by oral administration of target antigens was an important development that was successfully tested in 1980s. Since then, several studies have shown that feeding specific antigens can be used to prevent and control chronic inflammatory diseases in both animal models and clinically. Therefore, oral tolerance can be classified as an antigen-specific form of oral immunotherapy (OIT). In the light of novel findings on mechanisms, sites of induction and factors affecting oral tolerance, this review will focus on specific characteristics of oral tolerance induction and how they impact in its therapeutic application.

Nickel Allergy: Epidemiology, Pathomechanism, Clinical Patterns, Treatment and Prevention Programs

Nickel is the most common cause of contact allergy in the general population and the most frequently detected allergen in patients patch tested for suspected allergic contact dermatitis (ACD). ACD from nickel is a typical type IV hypersensitivity. Nickel allergy is mostly caused by nonoccupational exposure, such as jewelry and clothing decorations, metal tools, medical devices (mainly orthopedic and orthodontic implants, cardiovascular prosthesis), eyeglasses, utensils, keys, pigment for paint, cosmetics, and food (mainly legumes, chocolate, salmon, peanuts). Occupational exposure can involve several workers (mechanics, metalworkers, platers, hairdressers, jewelers, workers in the constructions and electronic industries), classically involving hands and forearms. The classic clinical pattern of ACD caused by nickel is characterized by eczematous dermatitis involving the sites of direct contact with the metal. Non-eczematous-patterns are reported, including lichenoid dermatitis, granuloma annulare, vitiligo-like lesions, dyshidrosiform dermatitis, and vasculitis. In the case of systemic exposure to nickel, sensitized patients could develop systemic contact dermatitis. Patch testing represents the gold standard for the diagnosis of ACD from nickel. Treatment includes avoidance of contact with products containing nickel and the patient's education about the possible use of alternative products. A recent EU nickel directive, regulating the content and release of nickel from products, has caused a decrease of nickel contact allergy in some European countries. Nickel allergy is a relevant issue of public health with significant personal, social, and economic impact. This review summarizes epidemiology, pathomechanism, clinical patterns, treatment, and prevention programs.

Update of the risk assessment of nickel in food and drinking water

The European Commission asked EFSA to update its previous Opinion on nickel in food and drinking water, taking into account new occurrence data, the updated benchmark dose (BMD) Guidance and newly available scientific information. More than 47,000 analytical results on the occurrence of nickel were used for calculating chronic and acute dietary exposure. An increased incidence of post-implantation loss in rats was identified as the critical effect for the risk characterisation of chronic oral exposure and a BMDL 10 of 1.3 mg Ni/kg body weight (bw) per day was selected as the reference point for the establishment of a tolerable daily intake (TDI) of 13 μg/kg bw. Eczematous flare-up reactions in the skin elicited in nickel-sensitised humans, a condition known as systemic contact dermatitis, was identified as the critical effect for the risk characterisation of acute oral exposure. A BMDL could not be derived, and therefore, the lowest-observed-adverse-effect-level of 4.3 μg Ni/kg bw was selected as the reference point. The margin of exposure (MOE) approach was applied and an MOE of 30 or higher was considered as being indicative of a low health concern. The mean lower bound (LB)/upper bound (UB) chronic dietary exposure was below or at the level of the TDI. The 95th percentile LB/UB chronic dietary exposure was below the TDI in adolescents and in all adult age groups, but generally exceeded the TDI in toddlers and in other children, as well as in infants in some surveys. This may raise a health concern in these young age groups. The MOE values for the mean UB acute dietary exposure and for the 95th percentile UB raises a health concern for nickel-sensitised individuals. The MOE values for an acute scenario regarding consumption of a glass of water on an empty stomach do not raise a health concern.

Symptoms of titanium and nickel allergic sensitization in orthodontic treatment

Aim

The study aimed to evaluate to which extent self-reported symptomatology, age, and sex are predictors of titanium and nickel allergic sensitization in patients in treatment with fixed orthodontic appliances.

Methods

The study analyzed 228 subjects aged 11–45 years (median 18, interquartile range 16–22); 68% of them were females, and 52% were adolescents. The allergic sensitization testing included epicutaneous patch test to titanium, titanium dioxide, titanium oxalate, titanium nitride, and nickel sulfate. The questionnaire on symptoms potentially linked to titanium and nickel sensitization was used.

Results

Prevalence of the allergic sensitization to titanium in patients undergoing orthodontic treatment was 4% (2% only to titanium without nickel) while to nickel 14% (12% nickel without titanium). Hypersensitivity to both metals at the same time was present in 2% of subjects. Sensitization to nickel was more common in females than in males (17 vs. 8%) and much more common in adults than in adolescents with small effect size (20 vs. 8%; p = 0.013). Sensitization to titanium was more common in females than in males (6 vs. 1%) with no difference in age. Multiple logistic regression analysis revealed that adult age increases the odds for being sensitized to nickel for 2.4 × (95% CI 1.1–5.6; p = 0.044) while watery eyes for 3.7 × (95% CI 1.2–11.1; p = 0.022). None of the symptoms were significant predictors of titanium sensitization.

Conclusion

Allergic sensitization to titanium and nickel are not very frequent in orthodontic patients, and self-reported symptomatology is a weak predictor of those sensitizations.

Systemic nickel allergy syndrome: epidemiological data from four Italian allergy units

The prevalence of nickel hyper-sensitivity varies widely in different countries, nevertheless it is the leading cause of contact dermatitis. The presence of nickel in the diet (mainly plant foods) in some nickel-sensitive subjects can provoke/aggravate eczema and systemic contact dermatitis as well as cause extra-cutaneous symptoms (respiratory, gastrointestinal, neurological). These symptoms, correlated to the ingestion of nickel-containing foods and beverages, in nickel patch test positive individuals, defines the so called Systemic Nickel Allergy Syndrome (SNAS), a condition successfully treated by oral desensitization. Although numerous studies have investigated the prevalence of contact nickel allergy or addressed the relationship between nickel intake and onset of systemic symptoms, to our knowledge no epidemiological studies have attempted to estimate the prevalence of SNAS. Therefore, we decided to evaluate consecutive patients (1,696), afferent to four allergy units in Sicily, a region of southern Italy, from October 2010 to March 2011. SNAS was confirmed in 98 patients (5.78 percent) of the 1,696 studied, suggesting that this clinical entity may be an emergent allergological condition rather than an occasional finding. The most common symptoms complained of in our population were cutaneous (51 patients), gastrointestinal (87 patients) and other systemic clinical manifestations (37 patients). Furthermore, 16 out of the 98 SNAS patients (16.3 percent) presented IgE-mediated food allergy with a statistically significant association (X2=16.950; P<0.0001), therefore suggesting underlying cross-facilitating pathways. These findings need confirmation on wider populations but may help allergists to suspect, during common clinical practice, that cutaneous and extra-cutaneous symptoms may be referred to nickel intake and deserve specific in-depth investigation.

Complementary and alternative medicine use in dermatology in the United States

BACKGROUND

Complementary and alternative medicine (CAM) has an increasing presence in dermatology. Complementary therapies have been studied in many skin diseases, including atopic dermatitis and psoriasis.

OBJECTIVES

This study sought to assess oral CAM use in dermatology relative to medicine as a whole in the United States, using the National Ambulatory Medical Care Survey.

DESIGN

Variables studied include patient demographic characteristics, diagnoses, and CAM documented at the visits. A brief literature review of the top 5 CAM treatments unique to dermatology visits was performed.

RESULTS

Most CAM users in both dermatology and medicine as a whole were female and white and were insured with private insurance or Medicare. Fish oil, glucosamine, glucosamine chondroitin, and omega-3 were the most common complementary supplements used in both samples.

CONCLUSIONS

CAM use in dermatology appears to be part of a larger trend in medicine. Knowledge of common complementary therapies can help dermatologists navigate this expanding field.

Nickel oral hyposensitization in patients with systemic nickel allergy syndrome

BACKGROUND

This is the first randomized, double-blind, placebo-controlled trial (EUDRACT No. 2009-013923-43) evaluating nickel oral hyposensitizing treatment (NiOHT) in patients with "systemic nickel allergy syndrome" (SNAS), characterized by Ni-allergic contact dermatitis and systemic reactions after eating Ni-rich food.

METHODS

Adults with positive Ni-patch test, who reported symptoms suggesting SNAS, which improved after Ni-poor diet, and were positive to Ni-oral challenge were eligible. Patients were randomly assigned to three treatments (1.5 μg, 0.3 μg, or 30 ng Ni/week) or placebo for a year, with progressive reintroduction of Ni-rich foods form the 5(th) month. Out of 141 patients randomized, 113 completed the trial. Endpoints were efficacy and tolerability of treatment.

RESULTS

During Ni-rich food re-introduction, the 1.5 μg Ni/week group had a mean VAS score significantly higher than placebo (p = 0.044), with significant improvement of gastrointestinal symptoms (p = 0.016;) and significantly fewer rescue medications. Cutaneous manifestations also improved but without reaching statistical significance. After the treatment, oral challenge with higher Ni doses than at baseline were needed to cause symptoms to flare-up in significantly more patients given 1.5 μg Ni/week than placebo (p = 0.05). Patients reported no side-effects.

CONCLUSIONS

NiOHT is effective in SNAS, in particular on gastrointestinal manifestations, with trend toward improvement of cutaneous symptoms.