Contact dermatitis happens when your skin reacts to a substance. There are different types of contact dermatitis depending on the type of substance.
Substances that cause contact dermatitis include:
- irritants - substances that damage the outer layer of skin
- allergens - substances that cause your immune system to react in a way that affects the skin
Allergic contact dermatitis
Allergic contact dermatitis is a delayed allergic reaction to a specific substance.
The first time you're in contact with an allergen, your body becomes sensitised to it. But your body does not react to the allergen straight away.
When you're in contact with the allergen again, your immune system may react. A reaction can happen at the next exposure or may not happen for months or years.
Even a small amount of the allergen can make your skin itchy and inflamed. The delayed reaction can make it difficult to identify the cause of the reaction.
Allergens that can cause contact dermatitis include:
- cosmetic ingredients such as preservatives, fragrances, hair dye and nail varnish hardeners
- metals such as nickel or cobalt in jewellery
- rubber or latex
- textiles and the dyes and resins in textiles
- strong glues such as epoxy resin adhesives
Irritant contact dermatitis
Irritant contact dermatitis can happen to anyone after contact with an irritant.
Common irritants include:
- soaps and detergents
- hand sanitisers
- water and frequent hand washing
- saliva - can cause a rash on your baby's chin (dribble rash)
- pee - can cause nappy rash
Heat, cold, dry air and rubbing against the irritant can make your symptoms worse.
Contact with irritants or allergens at work
You may be more at risk of contact dermatitis if you work with irritants or allergens in your job. You are also at risk if you work with water a lot.
This is called occupational dermatitis.
Occupational dermatitis is more common in some jobs, including:
- agriculture and construction workers
- beauticians and hairdressers
- chemical workers and cleaners
- cooks and caterers
- metal and electronics workers
- health and social care workers
- machine operators, mechanics and vehicle assemblers
Content supplied by the NHS and adapted for Ireland by the HSE
