Contact dermatitis can cause skin to become inflamed (irritated), blistered, dry, thickened and cracked.
Lighter skin can become red, and darker skin can become dark brown, purple or grey.
These symptoms can develop on any area of the body, although the hands and face are most often affected.
Symptoms caused by an irritant usually appear within 48 hours, or even immediately. Milder irritants (such as soap and detergents) may not cause problems immediately – you may need frequent exposure to these before they cause problems.
Symptoms caused by an allergen, such as make-up or metal jewellery, often take several days to develop.
If you can avoid being re-exposed to the substance responsible for the reaction, your skin will usually clear up within a few days or weeks.
However, some people experience severe and long-lasting symptoms, which may affect their quality of life.
Depending on the substance that caused the reaction, you may also experience some additional symptoms.
For example, allergens may cause affected areas of the skin to itch and irritants may cause a burning or stinging sensation.
Occasionally, areas of skin affected by contact dermatitis can become infected. Signs of an infection can include:
Seek immediate medical advice if you think your skin may have become infected, as you may need to take antibiotics.