Everyone’s skin condition is not the same; some of the people have very sensitive skin. For example, allergic reactions or irritation and itching could be triggered just by getting in contact with certain materials or even using certain products could cause an allergy.
If you have sensitive skin always choose a product that states that it can be used on sensitive skin. And be aware of any material that could cause irritation. We are all different; there are degrees in skin sensitivity that varies from person to person so get to know your skin intimately.
Certain chemicals in detergents and solvents will affect all skin types; however, the affect on those with “normal” skin is negligible in comparison. Individuals with sensitive skin, however, can have severe reactions when these chemicals, for example, come in to contact with the skin due to a lower tolerance threshold. Products that are labeled for use on sensitive skin generally avoid the use of potential irritants. Those products would not affect normal skin.