The question of whether wearing gold is harmful often comes up. Pure gold itself is largely biologically inert and safe for human contact, as this noble metal does not readily react with the body’s tissues or fluids. However, the jewelry industry rarely uses pure gold because it is too soft for everyday wear. It is mixed with other metals, known as alloys, to create a more durable material. The potential health concerns associated with gold jewelry are almost entirely due to these metallic additives.
Understanding Gold Purity and Alloys
Gold purity is measured using the karat system, where 24 karat (24k) represents 100% pure gold. Because pure gold is relatively soft and prone to scratching, it must be alloyed with other metals to increase its strength and durability for jewelry use. This alloying process also allows manufacturers to alter the color of the final product, creating options like white or rose gold.
The karat number indicates the proportion of gold in the mixture; for example, 18k gold contains 75% gold, and 14k gold contains 58.3% gold. The remaining percentage consists of various alloy metals, which are responsible for the majority of adverse reactions. Common metals mixed with gold include copper, silver, zinc, palladium, and nickel.
The Primary Health Concern: Allergic Contact Dermatitis
The most frequent health issue arising from gold jewelry is Allergic Contact Dermatitis (ACD), which is a localized skin inflammation. This reaction is caused not by the gold itself, but rather by the other metals that leach out of the alloy and penetrate the skin. Nickel is the most common culprit, as it is a potent sensitizer often used in lower-karat gold, particularly in white gold alloys to achieve a silvery color.
The reaction is classified as a Type IV hypersensitivity, a delayed-type allergy where the immune system recognizes the metal ions as foreign invaders. Once sensitized, subsequent exposure triggers a T-cell mediated response. Symptoms typically manifest as redness, persistent itching, a rash, and sometimes blistering at the site of contact, often appearing 12 to 72 hours after exposure.
Individuals prone to metal sensitivities can mitigate this risk by selecting jewelry with a higher gold content, such as 18k or 22k, which contain fewer base metals. White gold pieces, which often contain nickel, are a concern unless plated with rhodium, a hypoallergenic metal barrier. Applying a clear barrier, such as a specialty coating or clear nail polish, to the parts of the jewelry that touch the skin can also help prevent the leaching of allergenic metals.
Risks Associated with Plating and Lower-Grade Jewelry
Health risks extend beyond standard alloy allergies, particularly with gold-plated or low-grade jewelry. Gold plating involves applying a very thin layer of gold onto a base metal, often a cheaper alloy high in copper or nickel. Over time and with repeated friction, this thin gold layer wears away, exposing the allergenic base metal underneath.
Once the plating is breached, the underlying metals come into direct contact with the skin, triggering the same ACD reaction. This exposure risk is heightened in items like rings and bracelets that experience constant abrasion. While this is primarily a dermatological issue, a more severe risk is associated with toxic heavy metals found in some inexpensive costume jewelry.
Metals such as lead and cadmium have historically been used in low-grade alloys or soldering points to add weight, stability, or color. These heavy metals pose a toxicological risk, especially to children, as they can be absorbed through broken skin or if the jewelry is mouthed or swallowed. Lead exposure is associated with neurodevelopmental problems, while cadmium is a known carcinogen that can cause kidney and bone damage.
While regulations have reduced the prevalence of lead, cadmium remains a concern in less regulated products. For the average adult, dermal exposure to these heavy metals from solid gold is highly unlikely. Choosing jewelry from reputable sources and avoiding low-cost, unregulated pieces is the most effective way to prevent exposure to these hazardous substances.