Brass, an alloy of copper and zinc, is widely used in jewelry, instruments, and hardware. While true allergies to copper or zinc are rare, adverse skin reactions to brass items are common. These reactions are almost always a form of delayed-type hypersensitivity known as Allergic Contact Dermatitis (ACD).
The True Allergen in Brass
The skin reaction associated with brass is typically not caused by the copper and zinc base metals. Instead, the primary culprit is often nickel, a metal frequently added to brass to enhance its strength, durability, and color. Brass alloys containing nickel are much more likely to trigger a sensitivity response in individuals already allergic to nickel.
The reaction begins when the brass is in prolonged contact with the skin, especially when sweat is present. Sweat acts as a corrosive agent, causing minuscule nickel ions to leach out of the alloy. These released nickel ions penetrate the skin and bind to the body’s proteins. The immune system recognizes this complex as foreign and mounts a defense, which is the allergic response.
Recognizing Allergic Contact Dermatitis
The symptoms of an allergic reaction to the nickel within brass are characteristic of Allergic Contact Dermatitis. The reaction appears only on the specific area of the skin that had direct and prolonged contact with the metal. Common locations include the earlobes, the wrist beneath a bracelet or watch clasp, or the waistline from a belt buckle.
Initial signs include an itchy, red rash that may be accompanied by small bumps or vesicles. In more severe cases, the skin can become swollen, blistered, or develop weeping sores. The onset of these symptoms is usually delayed, appearing anywhere from 12 to 48 hours after exposure, which can make identifying the source challenging. For a definitive confirmation of a nickel allergy, a dermatologist can perform a patch test, which involves applying small amounts of potential allergens to the skin and observing the reaction.
Treatment and Prevention Strategies
Treatment
The immediate treatment for an allergic rash involves soothing the irritated skin and reducing the immune response. Over-the-counter topical corticosteroids, such as hydrocortisone cream, can be applied to decrease inflammation and itching. Cool compresses also provide symptomatic relief. For persistent itching, oral antihistamines can help manage the discomfort. If the rash is widespread or does not improve with over-the-counter treatments, a healthcare provider may prescribe stronger topical steroids or a short course of oral corticosteroids. The most effective long-term strategy is complete avoidance of the allergen.
Prevention
To prevent future reactions, the primary focus is on creating a barrier between the skin and the nickel-containing brass. One common method is applying a coat of clear nail polish to the surface of the brass item that touches the skin. Specialized metal sealants are also available that offer a more durable barrier. When purchasing items that will have prolonged skin contact, choosing alternative metals is the most reliable prevention method. Hypoallergenic options include:
- Surgical-grade stainless steel
- Titanium
- Platinum
- 14-karat gold or higher