ABSTRACT
PREDICTING ADVERSE SKIN EFFECTS Primary Dermal Irritation Erythema occurs when the concentration of an irritant and the time and conditions of skin exposure, exceeds a critical threshold level. Redness is usually localized to the exposure site. It may occur rapidly after the first exposure to an acute irritant or after several applications of a weaker or cumulative irritant. Diagnostically, irritation is frequently differentiated from sensitization reactions by factors such as the following:
l The composition and dose of the product l If the response occurs after the first usage l Its rapid onset after usage l The type and spreading of the reaction l How long the erythema and/or swelling lasts
Lotion manufacturers routinely probe for this type of information when consumers complain concerning an adverse reaction and may utilize a dermatologist to diagnose or followup as appropriate. Ingredients that can cause primary irritation in lotions are frequently anionic surfactants used as emulsifiers, or AHAs that are added for their antiaging benefits.
