Preservatives - Toxic Beauty

Along with fragrances, preservatives are one of the primary cosmetic causes of contact dermatitis. Preservatives are used in cosmetic products containing water to protect the product from becoming contaminated with microbes that might otherwise cause infections. 

Parabens are the most commonly used preservatives, followed by Kathon CG, which consists primarily of methylchloroisothiazolinone and methylisothiazolinone. Kathon CG and many other preservatives have been identified as contact allergens and sensitizers. Research has suggested that most instances of contact allergy bare caused by applying moisturizing creams to slightly damaged skin.

Reference: Toxic Beauty: Dawn Mellowship