Contact dermatitis is an allergic reaction to something touching the skin that results in an itchy rash. The most common example is poison ivy. However, there are many things in our daily personal products like lotions and shampoos that can also cause this, with the most common culprits being different fragrances or preservatives.
Other common causes of contact dermatitis are metals like nickel, and chemicals or cleaning agents we may come into contact with at work or home. It is not always a new product causing the rash. Unfortunately, the problem can be the same soap, make-up or hair product you may have been using for many years.