What is chrome and where is it found?
Most people relate chrome to the bright, shiny and durable finish of some metal products. However, contact with chrome-plated objects is an unlikely cause for chrome allergy. It is the chromium salts (chromates) used as an ingredient in the manufacture of many other products such as cement, mortar, leather, paints and anticorrosives that are the cause of chrome sensitivity. Most exposure is via the workplace, principally from cement and mortar used in the building industry, but is not limited to this. The table below shows some of the many sources of chromates and where or how we may come into contact with them either at home or at work.
|Home/personal sources||Work sources|
Positive patch tests
to potassium dichromate
Hand dermatitis due to
contact with cement
What are the reactions to chrome allergy?
Reactions to contact with chromates in an allergic individual include allergic contact dermatitis and irritant dermatitis. It may cause an airborne contact dermatitis. In addition chrome exposure may lead to ulceration of the skin and perforation of the nasal septum. Chrome ulcers and nasal septum perforation are most commonly seen in industrial exposure cases and may occur without accompanying allergy to chromates.
|Features of chrome ulcers and nasal septum perforation|
Cement dermatitis is most prevalent in construction workers but may occur in artists, DIY homebuilders or other individuals who are exposed to cement through work or a hobby. Dichromates in cement are not the only cause of cement dermatitis, they only account for the allergic contact dermatitis reactions. Primary irritant reactions of cement dermatitis include dryness and fissuring of the skin caused by the drying (hygroscopic) properties of cement, and injury or ulcers to skin caused by mechanical irritation due to rough silica particles in cement. Individuals can develop cement dermatitis after working for many years without any problems.
Am I allergic to chrome?
Chrome allergy is diagnosed from the clinical history and by performing special allergy tests, i.e. patch tests, using a solution of potassium dichromate.
|Features of a positive patch test to potassium dichromate ion|
It appears that chrome dermatitis can persist in people even after they change occupations and are no longer exposed to chromates. Approximately two thirds of those sensitive to chromates will still be allergic even when tested several years later. The reason is unknown but it may be that chromates may take a long time to leave the skin.
Management of chrome allergy
Avoidance is the only long-term management strategy for chrome allergy. Dermatitis caused by chromates can become a chronic debilitating problem so early diagnosis, followed by measures taken to minimize exposure or cease all contact with chromates is key to the management plan. De-sensitisation or hardening to chromates should not be relied upon.
Once the dermatitis appears on the skin, treatment is as for any acute dermatitis/eczema, i.e. topical corticosteroids, emollients, treatment of any secondary bacterial infection (Staphylococcus aureus), etc. Because chromate dermatitis is prone to dryness and fissuring, secondary bacterial infection is a real concern and a broad spectrum topical antibiotic preparation is usually used in conjunction with anti-eczema treatment.
Where avoidance is not achievable, several methods have been used to try to minimize exposure.
|Methods to minimize chromate exposure|
What should I do to avoid chrome allergy?
In the workplace try to avoid exposure to chromates, however this may not be practicable thus use measures to minimize exposure as described above. Identify potential sources of exposure using Material Safety Data Sheets; these are required for all chemicals and substances that you may come into contact with in the workplace.
Outside of the workplace, the best way to avoid chrome allergy is by being aware of the possible sources of chromates. Wearing thick socks and reducing foot perspiration may help to reduce chromate-induced shoe dermatitis. Use only cosmetics that you know do not contain chromates. Avoid direct contact with matches and do not keep matches in clothing pockets. Thoroughly wash all clothes contaminated with chromates.
If you must use products that contain chromates, wear appropriate gloves or other protective clothing to avoid contact with your skin. Your dermatologist may have further specific advice, particularly if you are highly sensitive to chromates.
Alternative names for chrome
Chrome is also known by several other names. These include:
- Chromium salt
- Potassium dichromate
- Chromium sulphate
Avoid all of these. At work, request a material safety data sheet to help identify alternatives that are safe hence avoiding contact with material containing chromates.
CAS number: 7778-50-9
Formula: Cr2K207 (hexavalent form of chromium)
- Trivalent chromium compounds
Main sensitisers are the dichromates
0.5% potassium dichromate in petrolatum
|Sources of Exposure to Chrome|
On DermNet NZ:
- T.R.U.E. Tests: this site provides a wide range of information on contact dermatitis and contact allergy testing
- Allergy New Zealand
- Allergic contact dermatitis – Medscape Reference
- Shoe allergies a personal resource for those allergic to their shoes
- Leather and Shoe Research Association of New Zealand
See the DermNet NZ bookstore