Nickel allergy: symptoms, causes, diagnosis and treatment

By Cristiano Antonino On Feb 17, 2023

Nickel allergy is one of the main causes of allergic contact dermatitis (ACD). It can cause even major discomfort in daily life, due to the fact that this metal is found in many objects, from keys to kitchen utensils, but also in many foods, some of which form the basis of a regular diet

It is, however, crucial for the patient to detect it early enough to avoid complications, although serious ones are rarely observed.

There are behavioural and dietary pointers that, if implemented, alleviate symptoms, including avoiding smoking and being careful with tattoos.

What are the symptoms of a nickel allergy?

The first clear symptom of a nickel allergy is the appearance of contact dermatitis after coming into contact with objects containing the metal (e.g. costume jewellery), especially on the hands, earlobes or on the mucous membrane of the oral cavity.

Specifically, one may observe the appearance of redness, blisters and vesicles that may form scabs when they break.

If contact with nickel is prolonged and/or repeated, the skin thickens and peels, and may take on a darker colour.

Since nickel is also contained in cosmetic products such as toothpaste, make-up, nail varnish or hair dyes, it can also cause problems for other parts of the body, both those that come into direct contact with it but also other areas that are more or less close by.

Generally, dermatitis caused by this type of allergy appears between 12 and 48 hours after exposure to nickel and can continue for up to two weeks.

In the case of frequent exposure to this metal, of course, the reaction can be much longer-lasting.

Causes of nickel allergy

As with all allergies, nickel allergy is also caused by a dysregulation of the immune system, which reacts to the presence of this metal to defend the body against its presence (even though it should not).

The metal is in fact recognised as a foreign component of the body and as such is attacked, thus provoking an inflammatory reaction characterised by the release of high quantities of histamine by mast cells, resulting in the appearance of severe itching at local skin level.

Once an allergy develops, the immune system is activated whenever the body comes into contact with nickel, triggering an allergic response.

Nickel exposure can occur in several ways

by ingesting food and water: nickel is present in some foods naturally, in varying amounts, while in other cases there may have been contamination from industrial waste that pollutes groundwater, not to mention pots and kitchen accessories used to cook food;
by aerial exposure through air pollution, tobacco smoke, fossil fuel smoke;
from skin contact through jewellery, coins, shampoos, detergents etc;
from chronic haemodialysis in patients with chronic renal insufficiency due to the chelating action of albumin.

There is no known common cause, but allergy can be at least partly attributed to a genetic predisposition. Another predisposing factor is sweating, which amplifies and accelerates the individual’s allergic response.

There are some individuals more at risk than others of developing nickel allergy, namely:

workers in the nickel and heavy metal industry
female sex
atopic individuals and/or those with other types of allergies
patients with a family history of other allergic diseases

In addition, obese individuals and those who use nonnickel-free piercings and earrings are also at risk.

How to diagnose nickel allergy

In order to diagnose a nickel allergy, it is first advisable to have an allergy examination, prescribed by the treating physician, during which the allergy specialist can analyse the patient’s skin manifestations and perform a specific test called a patch test.

This test involves the application on the patient’s back of patches containing the suspected allergenic substances, after which any appearance of local skin reactions is assessed after 48 to 72 hours.

If removing the nickel test patch shows that the skin is inflamed, then a certain level of sensitivity to the metal is confirmed.

A positive result does not always mean allergy, however, so it must be assessed on a case-by-case basis by the specialist.

After a positive patch test demonstrating nickel sensitisation, a low-nickel diet is administered generally for 3 weeks, i.e. foods such as spinach, cabbage, carrots, tomatoes, lettuce, maize, peas, asparagus, potatoes, onions, lentils, beans, figs, apricots, pears, blueberries, almonds, walnuts, hazelnuts, cocoa, tea, margarine, baking powder, wheat flour and buckwheat should be avoided.

After this period, the specialist performs an oral provocation test to confirm the suspicion.

Treatments and cures

Being a reaction induced by our immune system, nickel allergy is not curable but rather preventable by avoiding contact with any product containing this metal.

In cases of particularly severe reactions, the specialist may deem it indicated to prescribe drugs to relieve the symptoms, i.e. topical corticosteroid creams, creams with a soothing effect or tablets containing antihistamines and corticosteroids.

In selected cases of severe contact allergy or systemic nickel syndrome (SNAS), the allergist may decide to perform oral nickel desensitisation treatment under his or her strict supervision.

In cases where the allergy is still a suspicion and there is no definite and official diagnosis, the use of multivitamin supplements is discouraged and the elimination of cigarette smoking is strongly recommended.

There are also natural remedies that alleviate symptoms and can be combined with pharmacological treatment.

It is possible, in fact, to use herbs, flowers and leaves that improve the wellbeing of the intestine, for example herbal teas made with fennel, green aniseed, dill and coriander that help in cases of bloating, abdominal burning and intestinal disorders.

Nutrition and products

Unfortunately, nickel is present in many foods but it is not possible to know in advance the exact content in each one, as this depends on several factors such as the soil in which they are grown, the pesticides used and the equipment and substances used during the various steps of the production chain.

For this reason, the diet of a nickel-allergic person is highly restrictive, involving the elimination of very common foods in our diet, but also all nickel-containing kitchenware and utensils.

Finally, nickel is present in many cosmetics, beauty and personal care products, including hair dyes, toothpastes, shampoos, make-up and nail polishes.

Its presence, however, must be declared on the label, so these products can easily be avoided.

Can people with allergies get tattoos and piercings?

With regard to tattoos, nickel may be present both in the needle used to tattoo and in the injected substance; for example, paraphenylenediamine is a chemical agent used to fix colour, and is often responsible for redness, itching and swelling that appear in the affected area and that could develop into granulomas (subcutaneous nodules).

This is why it is a good idea to discuss the composition of the instruments and substances used with your tattoo artist.

Even before doing a piercing, it is a good idea to find out whether both the needle or other instruments with which the skin is pierced and the jewellery used (rings, bars or headbands) are nickel-free. Otherwise, dermatitis or other allergic reactions may occur.

Is smoking allowed?

Tobacco leaves, as well as smoke from combustion, contain a fair amount of nickel; the proximity of smoking to sensitive areas such as the mouth or eyes may therefore increase the risk of symptoms, i.e. eczema and dermatitis, occurring.

In addition, inhalation may result in some absorption of nickel through the respiratory route, with the risk of complications.

For all these reasons, cigarette smoking is not recommended in nickel-intolerant individuals.

The same applies to the electronic cigarette, as it contains the same amount of nickel as tobacco cigarettes and indeed, as it contains aluminium and iron, it appears to be even more harmful.

Nickel Allergy: What Objects And Foods To Avoid?

Food Allergies: Causes And Symptoms

Adverse Drug Reactions: What They Are And How To Manage Adverse Effects

Symptoms And Remedies Of Allergic Rhinitis

Allergic Conjunctivitis: Causes, Symptoms And Prevention

What Is And How To Read The Allergy Patch Test

Allergies: New Drugs And Personalised Treatment

Allergic Contact Dermatitis And Atopic Dermatitis: The Differences

Spring Arrives, Allergies Return: Tests For Diagnosis And Treatment

Allergies And Drugs: What’s The Difference Between First-Generation And Second-Generation Antihistamines?

Symptoms And Foods To Avoid With Nickel Allergy

Contact Dermatitis: Can A Nickel Allergy Be The Cause?