The recent surge in incorporation of metallic and metal oxide nanomaterials into consumer products and their corresponding use in occupational settings have raised concerns over the potential for metals to induce size-specific adverse toxicological effects. Although nano-metals have been shown to induce greater lung injury and inflammation than their larger metal counterparts, their size-related effects on the immune system and allergic disease remain largely unknown. This knowledge gap is particularly concerning since metals are historically recognized as common inducers of allergic contact dermatitis, occupational asthma, and allergic adjuvancy. The investigation into the potential for adverse immune effects following exposure to metal nanomaterials is becoming an area of scientific interest since these characteristically lightweight materials are easily aerosolized and inhaled, and their small size may allow for penetration of the skin, which may promote unique size-specific immune effects with implications for allergic disease. Additionally, alterations in physicochemical properties of metals in the nano-scale greatly influence their interactions with components of biological systems, potentially leading to implications for inducing or exacerbating allergic disease. Although some research has been directed toward addressing these concerns, many aspects of metal nanomaterial-induced immune effects remain unclear. Overall, more scientific knowledge exists in regards to the potential for metal nanomaterials to exacerbate allergic disease than to their potential to induce allergic disease. Furthermore, effects of metal nanomaterial exposure on respiratory allergy have been more thoroughly-characterized than their potential influence on dermal allergy. Current knowledge regarding metal nanomaterials and their potential to induce/exacerbate dermal and respiratory allergy are summarized in this review. In addition, an examination of several remaining knowledge gaps and considerations for future studies is provided.

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Metal nanomaterials: Immune effects and implications of physicochemical properties on sensitization, elicitation, and exacerbation of allergic disease

The use of metals in the medical field has become increasingly prevalent over the past few decades. Patients find themselves being exposed to metals in a variety of ways, ranging from external exposure to instruments such as the stainless steel in surgical blades to internal exposure via medical devices being implanted in their bodies. There has been growing interest in the possibility of developing hypersensitivity reactions to constituent metals in medical implant devices, both in cutaneous and systemic forms. Hypersensitivity reactions to metals are uncommon, but they are reported and require appropriate evaluation and management, particularly if they are symptomatic. In view of the lack of consensus in the field on the appropriate steps to evaluate and manage patients with suspected metal hypersensitivity reactions, this review aims to analyze current evidence on hypersensitivity reactions to metallic implants in orthopedic surgery, endovascular surgery, obstetrics and gynecology, and dental surgery.

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Hypersensitivity Reactions to Implanted Metal Devices: Facts and Fictions.

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.

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

Background and Aim: Oral lichen planus (OLP) is a chronic, inflammatory, T-cellmediated autoimmune oral mucosal disease. Oral lichenoid lesions develop as a type IV hypersensitivity reaction. Both of these entities are potential precancerous conditions; this adds to their clinical significance. The purpose of this literature review was to detect the similarities and the differences of these lesions to enhance the information of colleagues in managing these groups of patients. Materials and Methods: For this review, we searched Cochrane, Medline, and Embase databases from January 1990 to the end of October 2018. A total of 96 published papers, including review papers, case reports, cohort studies, case-control studies, and meta-analysis studies, were included and analyzed. Results: OLP and oral lichenoid reactions are two distinct diseases. They can be clinically similar but they have different etiologic factors. A histopathological study is necessary to differentiate them. Conclusion: The definitive diagnosis of these conditions is extremely important given their potentially premalignant nature. A timely diagnosis probably results in proper management. Based on the present research, the final differentiation between OLP and oral Lichenoid reactions relies on both clinical and histopathological manifestations according to the modified World Health Organization (WHO) criteria.

Oral Lichen Planus or Oral Lichenoid Reaction? A Literature Review

Allergic contact hypersensitivity to metals is a delayed-type allergy. Although various metals are able to induce an allergic reaction, nickel is the most frequent cause of metal allergy worldwide. The high prevalence of skin sensitization to that metal is the result of an ubiquitous exposure, being contained in different everyday things, such as detergents, cheap jewelry, cosmetics, coins, buttons, zippers, eyeglasses, buckles, clasps, inks, dental prosthesis and foods even. However, nickel is able to induce a wide range of morphological and clinical patterns, ranging from simple allergic contact dermatitis to systemic contact dermatitis and systemic nickel allergy syndrome. The latter seems to be promoted by nickel rich-foods or through endogenous route caused by metal implants which seem to elicit mainly in loco symptoms, sometimes with catastrophic consequences as aseptic bone necrosis following the implantation of hip prosthesis.

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Nickel Hypersensitivity: A General Review on Clinical Aspects and PotentialCo-Morbidities

A middle aged patient came to our dental out patients department with a complaint of burning sensation in right buccal mucosa and right side of tongue and an inability to eat spicy foods since a few months. Medical and family histories were non-contributory. The patient was not on any long-term medication either. However, the patient gave a dental history of fabrication of metal bridge for missing mandibular right molar a few years back. Intraoral examination revealed …

https://casereports.bmj.com/content/casereports/2013/bcr-2013-009754.full.pdf

Suraj Appasaheb Chougule

Papers

Oral lichenoid reaction due to nickel alloy contact hypersensitivity.