To understand how topical corticosteroids work, it is first useful to learn more about the biological processes that cause inflammation.
Inflammation
When a part of your body is affected by infection, your immune system will respond by flooding the area with infection-fighting antibodies. The antibodies limit the spread of infection and kill off the virus, bacteria or fungus that is responsible for the infection. The immune system is the body’s natural defence system against illness and infection.
However, these chemicals will cause the affected area of the body to become swollen, warm and, in the case of your skin, reddened. This is known as inflammation.
Inflammation is usually a useful biological process. But there are times where the immune system malfunctions and triggers inflammation even though no infection has occurred. This ‘misfiring’ of the immune system is the main cause of many common skin conditions, such as atopic eczema and psoriasis.
How topical corticosteroids work
There are four main ways that topical corticosteroids help to treat skin conditions such as atopic eczema. They:
- block some of the effects of the chemicals that the immune system uses to trigger the process of inflammation
- make the immune system less sensitive to outside agents, which means it is less likely to cause symptoms that affect the skin
- help regulate the production of new skin cells – this can be useful in treating certain skin conditions, such as psoriasis, where the symptoms are caused by new skin cells being produced too quickly
- narrow the blood vessels in the affected areas of skin – this reduces the amount of inflammatory chemicals that are sent to the skin
