Allergies to cosmetics can happen at any time – even to products you’ve used and loved for years.
To find out whether your rash is linked with cosmetics – rather than eczema, say, or contact dermatitis – stop using all likely culprits immediately. Then apply cosmetics one at a time, twice a day, to the inside of your arm, to see if you develop a rash.
If you must wear make–up, add one product at a time. This should help you identify the trouble–trigger.