Metal allergy is a relatively common type of intolerance caused by the ingestion of metal element ions into the human body and their binding to proteins. Symptoms depend on the type of interaction with the provoking substance, dermatitis is most often registered in the form of redness, itching, burning. Diagnosis is made on the basis of the results of examination and examination of the patient’s anamnesis, in some cases, the method of allergological tests is used. Treatment consists in eliminating contact with metal, carrying out symptomatic and supportive measures.
L23.0 Allergic contact dermatitis caused by metals
Metal allergy is registered in 7-10% of the world’s population, but a significant proportion of cases remain undiagnosed. This is facilitated by the weakness and non-specificity of the symptoms of the disease, their slow development, as well as the tendency of pathology to spontaneous disappearance. The widespread use of the condition is due to the mass use of metal products in the form of clothing items, jewelry, household items, dishes. Sometimes allergic reactions can be caused by metal, which is part of dental and surgical instruments, cosmetics, medicines. It has been established that adults predominate among patients, whereas in children such a problem is much less common. This distinguishes metal ion intolerance from other types of allergies.
Hypersensitivity develops only to some chemical elements from the group of metals. The causes of its occurrence have not been reliably established, the influence of environmental and genetic factors is assumed. An auxiliary role in the development of skin forms of this allergy is played by increased sweating or individual characteristics of the sebaceous glands. This facilitates the penetration of ions into the epidermis, which is necessary for the development of the reaction. Not only “pure” metals can provoke the occurrence of intolerance, but also compounds containing them in their composition. Most often , pathology is caused by the body ‘s contact with the following substances:
- Nickel. Causes a significant part of cases of allergic dermatitis resulting from contact with metals. It is a part of alloys, from which many elements of clothing, costume jewelry, medical instruments are created.
- Chrome. It is widely used as an anticorrosive and decorative coating of products. Penetrating into the tissues, it contributes not only to allergic reactions, but also to the formation of some toxic compounds (for example, chromic acid salts).
- Aluminum. Previously used for the production of tableware, currently its use in everyday life is greatly reduced. Aluminum salts are found in antiperspirants and other cosmetics.
- Zinc. It is a popular metal in therapeutic dentistry, where filling materials are made on its basis. Zinc compounds are part of some types of ointments and cosmetics.
Cobalt and mercury are often added to the list of elements that provoke an allergy to metal, but this is not entirely correct. When the body comes into contact with these substances or their alloys, the released ions really cause characteristic symptoms (irritation and inflammation of tissues). However, they are caused not by immunological processes and hypersensitivity, but by the toxic properties of these elements. Precious metals (gold, silver, platinum) in their pure form rarely provoke pathological reactions. Itching and irritation that occur when wearing jewelry are explained by the presence of additives of other substances in them – for example, copper.
The pathogenesis of metal allergy is based on the penetration of ions into tissues that dissolve in water and can interact with biological molecules. Diffusion of metal particles from the surface of jewelry, clothing items and other products occurs due to skin secretions (sweat). They dissolve microscopic amounts of metal, promote their penetration into the epidermis and the surface layers of the dermis, therefore hyperhidrosis, elevated air temperature and other factors that increase the production of sweat glands lead to a faster development of an allergic reaction. When metal products come into contact with other liquids (saliva, lymph, blood), the dissolution process goes even faster, hypersensitivity manifests earlier.
Metal ions by themselves are unable to trigger immunological reactions, since they are defective antigens. However, they interact with some proteins of the body’s tissues, changing their properties and turning them into peculiar allergens. The further course of the pathological process may be different, most often there is a 4th type of hypersensitivity. Reagin variants of intolerance with the release of IgE and histamine are possible. Other types of reactions to metal differ only by the penetration of ions into tissues – for example, through the mucous membranes of the mouth (from crowns and fillings) or with food. In the latter case, the symptoms of the disease are practically indistinguishable from food allergic reactions.
Symptoms of metal allergy
The most common variant of pathology is contact dermatitis, which occurs in the area of prolonged contact with a metal product (plaque, buttons, jewelry). At first, when metal comes into contact with the skin, no reactions are observed. The duration of the asymptomatic period depends on many factors – the quality of the alloy, the level of activity of sweat glands, sensitization of the body. Then a zone of redness, itching, and puffiness forms on the skin. Most often, such manifestations are found on the stomach (from the belt buckle), neck, wrists and ears (from chains and jewelry). In women, irritations can be registered on the back and shoulders due to the metal elements of the bra.
If symptoms are ignored and continued contact with a metal object, erosions and abrasions may occur on the surface of the skin. They are caused by combing and violation of microcirculation processes in the affected area. Systemic manifestations (fever, general malaise) allergies develop extremely rarely. The symptoms are enhanced by direct contact of tissue fluids with metal elements – for example, during piercing, the installation of various implants. Inflammatory phenomena can be aggravated by weeping eczema and urticaria.
In dentistry, some of the allergic complications after filling or implantation are caused by intolerance to metal materials and tools. They are manifested by the development of stomatitis – swelling of the oral mucosa, the appearance of erosions and ulcers on its surface. With a sensitized body, such symptoms occur 2-3 days after medical manipulations. Allergy, which develops in response to the use of metal ions with food, has some features. For example, nickel intolerance in this case is manifested by an erythematous rash in the genital area and anal opening.
Severe or dangerous complications with metal allergy are practically not found. Presumably, some cases of Quincke’s edema after dental manipulations can be explained by intolerance to cermet or zinc-containing filling material. The skin manifestations of the disease can be complicated by a secondary bacterial infection introduced by combing and damage to the epidermis. The development of bacterial asthma in workers of the metallurgical industry is considered by some experts as one of the consequences of hypersensitivity to metal dust.
The definition of metal allergy is handled by an allergist. Often, patients are referred to him by a dermatologist, to whom most patients initially turn. In some cases, diagnosis may be difficult – skin manifestations of pathology are nonspecific, they cannot always be associated with the impact of metal materials. The effectiveness and reliability of laboratory tests or test systems for the disease is very low. For this reason, an important role in determining allergies is played by a survey and anamnesis study, as well as indirect signs of pathology. Detection and confirmation of hypersensitivity is performed according to the following algorithm:
- Physical examination. When the skin is affected, redness, erythematous rashes are detected, sometimes peeling. Frequent localization – lower abdomen, wrists, neck, fingers, earlobes, armpits. Sometimes allergic stomatitis develops – erosions, ulceration, swelling of the mucous membranes are detected in the oral cavity.
- Collecting anamnesis. During the questioning, the doctor finds out with what objects (items of clothing, jewelry) the affected areas of the skin have been in contact in the last few days. The specialist specifies how long the patient has been visiting the dentist and for what reason (with inflammation of the oral mucosa). If a food allergy to metal is suspected, the patient’s diet is studied before the development of pathology.
- Allergic tests. Specific skin tests with allergen standards for this type of intolerance have not been developed. A variant of a provocative test can be used, in which the patient comes into contact with the metal for some time (from several hours), then a specialist is examined a day later. The food type of allergy can be determined by means of an elimination test – the elimination of foods with a presumably high content of metal ions from the diet.
When determining pathology, it is taken into account that contact not only with free metals, but also with their compounds can cause a reaction. The latter may be part of cosmetics, antiperspirants, and some medications. Differential diagnosis of the disease is carried out with contact dermatitis of a different etiology and other skin pathologies of an inflammatory nature. When the mucous membranes of the oral cavity are affected, stomatitis of infectious genesis is excluded. Food varieties of metal intolerance are practically indistinguishable from ordinary food allergies, only some variants (for example, hypersensitivity to nickel) have clinical features.
Treatment of metal allergy
In practical allergology, therapeutic measures for this disease are reduced to the elimination of contacts with provoking metals and symptomatic treatment. With cutaneous forms of pathology, the patient should refuse to use jewelry, clothing with metal products (fasteners, buckles, buttons). If the allergy is caused by cosmetics, it is necessary to completely exclude their use. Allergic stomatitis on the background of dental fillings, implants, braces is eliminated after the removal of elements based on metal alloys. Treatment of food intolerance to metal-containing products requires correction of the diet, sometimes – changing of cooking utensils for ceramic or enameled.
Skin disorders with allergies are facilitated by the use of local remedies (ointments, gels) containing glucocorticoids. The latter effectively eliminate itching and reduce the activity of inflammation. In severe stomatitis or angioedema, prednisone is prescribed. In rare cases, antimicrobial drugs are used for infectious complications (suppuration). Antihistamines in this pathology have limited effectiveness, but in many patients they accelerate the disappearance of skin symptoms. Hardening and vitamin therapy are also recommended, which help strengthen the immune system and correct its activity.
Prognosis and prevention
The prognosis of metal allergy is favorable, the disease rarely leads to a serious condition or complications. There may be certain inconveniences associated with the need to avoid contact with metallic substances or cosmetic and medicinal products based on them. Pathology imposes restrictions on the list of dental procedures available to the patient, there are special requirements for the materials used in this case. Canned foods should be avoided in the diet, especially in metal containers. There is no specific allergy prevention, there are only general recommendations – hardening, providing the body with vitamins and trace elements, avoiding long-term wearing of products made of base metals.