allergopedia

Home | About | Table of contents | Sensitizers from A to Z | For Authors | Scientific Advisory Board | Editors and Publishers


Palladium allergy

Radoslaw Spiewak

Institute of Dermatology, Krakow, Poland

Key words: palladium allergy, contact allergy, allergic contact dermatitis.

Suggested citation format: Spiewak R. Palladium allergy. Allergopedia. 2025; 01: 03. DOI: to be announced

Palladium (chemical symbol: Pd) is a metal used in automotive exhaust catalytic converters (possible release into the atmosphere and the risk of airborne human exposure). It is also an essential element in computers, mobile phones, and LCD monitors. It is also used in the electroplating of watch parts. Palladium alloys are used in dentistry (dental implants) and orthopedics (endoprostheses, bone fixation systems). Until two decades ago, positive patch tests with palladium were generally considered cross-reactions to nickel, as people did not come into contact with this metal in everyday life. However, due to technological advances and changes in legal regulations (restrictions on nickel in some consumer products), palladium has become more widespread in everyday environment. Among others, due to restrictions on nickel content in jewellery introduced in Europe, palladium has replaced it in alloys known as "white gold" (palladium gold). Palladium is also a basic component of automotive exhaust catalytic converters, from where it can be released into the environment if used improperly. Increased environmental exposure may explain the observed cases of primary sensitization to palladium in which patch tests to nickel remain negative.

Clinical symptoms of palladium allergy

In most cases palladium causes skin inflammation (allergic contact dermatitis or eczema) limited to areas directly exposed to palladium by skin contact. Typical symptoms of palladium allergy include patches of itchy rash in the area of contact with metal objects releasing palladium, like jewellery, metal buttons, rivets, zippers, buckless of garments, or areas exposed to contact with palladium-releasing tools. Systemic reactivation of allergic contact dermatitis, i.e., dermatitis due to systemic exposure via ingestion or inhalation, e.g., from orthodontic appliances are possible, but infrequently reported. Hematogenous eczema due to absorption of palladium at the primary contact site and redistribution to other skin areas via bloodstream is also possible, however, has not been reported until present.

Palladium in cosmetics

Palladium and its compounds are relatively rarely used in cosmetics. As of 2022, metallic palladium was found in the European cosmetic ingredient database, although its intended use (as an ingredient in nail polishes, glitter?) is unknown. Sulfurized palladium salt from lavender extract acts as a fragrance.

  • INCI*: PALLADIUM
  • INCI: COLLOIDAL PALLADIUM
  • INCI: LAVANDULA OFFICINALIS EXTRACT SULFURIZED PALLADIUM SALT

INCI: International Nomenclature of Cosmetic Ingredients - unified, international names for cosmetic ingredients. Information about ingredients is provided on cosmetics packaging according to the INCI nomenclature. CI: Colour Index, a unique number of a dye in the Colour Index™ International (CI) reference database.

Synonyms and names for palladium and its compounds in English and other languages

Palladium; Dichloropalladium; Enplate activator 440; Palladium (II) chloride; Palladous chloride; Palladium dichloride; Palladium chloride; Pd; CAS# 7440-05-3; CAS# 97660-01-0; EC# 307-508-4; EC# 231-115-6

Available diagnostic methods and materials

At present, the only validated method of detecting palladium allergy is patch test performed in line with the current guidelines by national or intenational scientific societes, e.g., European Society of Contact Dermatitis. Patch test material available for testing includes:

  • Sodium tetrachloropalladate (II) hydrate 3% pet. (recommended by the author, part of the Polish Baseline Series)
  • Palladium (II) chloride 2% pet. (less sensitive than the above test preparation)

Please note: Blood tests for palladium allergy (mostly advertised as "lymphocyte transformation tests"), although popular in some countries, have not been approved as a diagnostic tool, and their use in allergy diagnosis is controversial.

Positivity rate

11.4-15.6% of patients eligible for patch testing.

Cross-reactivities, co-positivities and co-sensitizations

Nickel is the most frequent and best-known cross-reactity of palladium. In the past, positive reactions to palladium were considered as cross reactivity secondary to nickel allergy, due to similar atomic structure and chemical properties of both metals. Nowadays, however, palladium is increasingly present in the everyday environment and isolated allergy to palladium (concomitant negative test to nickel) becomes more prevalent; there are also patients in whom allergy to palladium seems to be the primary event with clinical relevance, while nickel allergy seems to be the actual cross-reactivity secondary to palladium.

Disclaimer

The above description does not exhaust all possible exposures and symptoms, and the hapten you are allergic to may also be present in other sources not listed above.Therefore, always check the composition of the products and substances you come into contact with, and if in doubt, consult a licensed physician, preferably a dermatologist or allergist.
The authors, reviewers, editors and publisher of this work have made every effort to ensure that the content presented reflects the current state of knowledge at the time of its preparation. However, scientific progress may render some information outdated or inaccurate. Therefore, the authors, reviewers, editors, and publishers of this work exclude all liability for damages that may arise as a result of using the information presented. Use of this work constitutes acceptance of this disclaimer and a waiver of any claims arising from its use.

References


Allergopedia online: https://allergopedia.info
The publisher allows a non-commercial use of the information contained in this journal,
provided that information about the original source is always clearly displayed (author name, article and journal title, DOI).
Any other uses require written permission from the publisher and copyright holder.
By using this content you accept copyright, terms of use and disclaimer.
Document created: 14 October 2025, last updated: 12 May 2026
Allergopedia™ is a EU-registered trademark
© Radoslaw Spiewak Instytut Dermatologii