Author: Vanessa Ngan, Staff Writer, 2002.
Chrome allergy is contact allergic dermatitis due to a delayed hypersensitivity reaction to chromium salts (chromates). These used as an ingredient in the manufacture of many other products such as cement, mortar, leather, paints and anticorrosives.
Most people relate chrome to the bright, shiny and durable finish of some metal products, but contact with chrome-plated objects is an unlikely cause for chrome allergy. Further investigation usually reveals nickel as the offending agent.
Most exposure to chromium salts is via the workplace, principally from cement and mortar used in the building industry, but there are many other sources of chromates.
Reactions to contact with chromium salts include:
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.
Chrome allergy is diagnosed from the clinical history and by performing special allergy tests, called patch tests, using a solution of potassium dichromate.
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.
Avoidance is the only long-term management strategy for chromate allergy. Dermatitis caused by chromates can become a chronic debilitating problem, so early diagnosis, followed by measures taken to minimise exposure or cease all contact with chromates is key to the management plan. De-sensitisation or hardening to chromates should not be relied upon.
Where avoidance is not achievable, several methods have been used to try to minimise exposure.
In the workplace try to avoid exposure to chromates, however this may not be practicable thus use measures to minimise 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.
Chrome is known by several other names. These include:
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)
Main sensitisers are the dichromates
0.5% potassium dichromate in petrolatum
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