250 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS is not well understood. Persons with fair skin who tan poorly seem to have a lower tolerance than other skin types. The relevance to eye area products of other factors disclosed by studies of facial stinging due to topically applied substances (4) merits investigation. Stinging and burning are experienced directly or soon after the application of eye makeup. While the discomfort may be considerable it is as a rule transitory and without residual effect. Subjective irritation may be induced by the evaporation of volatile ingredients, e.g., mineral spirits, isoparaffins, and cyclomethicone or by non-volatile chemicals such as propylene glycol, soap emulsifiers, surfactants, and other silicones. Unless the reaction is mild the product has to be discontinued. III. "ALLERGIC" CONJUNCTIVITIS Quotation marks are used to indicate that inflammation of the conjunctiva may be elicited by physical and chemical irritants as well as by allergens. Physical irritants include mascara that may be washed into the conjunctival sac by the lacrimal fluid or the inadvertent entry of lash extenders and flakes of eyeshadow. Solvents, surfactants, and soap emulsifiers are among the chemical irritants involved. Schorr (5) emphasizes the importance of the overuse of eyeliner and mascara and the application of eye cosmetics across the inner and outer canthi in the pathogenesis of allergic conjunctivi- tis. The clinical manifestations are puffiness of the eyelids, chemosis (edema of the conjunctiva), dilatation of the conjunctival vessels, and a watery discharge. Medicihals instilled into the eye and wetting agents for soft contact lenses may induce the same clinical response (6,7). •Allergic" conjunctivitis from eye makeup may be confused with atopic vasomotor rhinitis, vernal catarrh, and pink eye caused by the Koch-Weeks' bacillus (8,9). IV. CONTACT DERMATITIS OF THE EYELIDS AND PERIORBITAL AREA More often than otherwise, contact dermatitis of the periocular area can be traced to cosmetics used elsewhere and conveyed by the fingers to the eyelids, e.g., perfume, hair preparations (dyes, sprays, and setting lotions), facial products including wet facial tissue impregnated with formalin or benzalkonium chloride (Zephiran©), and to non-cosmetic causes such as medicihals, contact lens solutions, and household sprays (10-15). Some of the aforesaid causes may be missed because the sites of application are spared. 1. FORMS OF CONTACT DERMATITIS Eye area cosmetics may be the cause of allergic contact dermatitis or irritant (toxic) dermatitis. Photocontact dermatitis resulting from light activated chemicals that can act as antigens (haptens) has not been reported. This is not surprising since photosensitizing and phototoxic chemicals are rarely incorporated in periocular cosmetics.

REACTIONS TO EYE COSMETICS 251 Contact dermatitis resulting from eye area products is rarely severe and is manifested by periorbital erythema of varying degrees, some edema, scaling, itching, and burning. Irritant contact dermatitis is encountered more often than the allergic form. Although the cutaneous manifestations of both forms are virtually indistinguishable, the pathogenesis differs. 2. PATHOGENESIS Allergic contact dermatitis involves cell-mediated immunity and occurs only in individuals who are prone after adequate exposure to a sensitizing substance (16). Proneness may be a genetically determined trait influenced by environmental and local factors such as damaged skin and occlusion. The initial step in sensitization is the combination of the contacting hapten (chemical) with an epidermal protein to produce a hapten-carrier conjugate that is immunogenic. Re-exposure after a given period to the same or an immunologically related chemical is followed by an allergic reaction referred to as a delayed eczematous response, i.e., allergic contact dermatitis. The interval between the initial contact and the development of the allergic response, i.e., the sensitization (incubation) period varies considerably, rarely shorter than seven to ten days or it may- be a matter of months to years depending on the opportunity for exposure and the sensitizing potential of the chemical. Once established this form and allergy often persists for life. While sensitization to eye area cosmetics may develop de novo in the course of applying and reapplying a product, most reactions seem to occur in previously sensitized individuals who were exposed some time in the past to the same or related allergen in topical medicaments or their environment (11). The pathogenesis of irritant contact dermatitis is not entirely clear. Two types are recognized--the acute type elicited by a single application of a strong irritant such as caustic materials and the chronic form in response to mild (cumulative) irritants requiring multiple exposures Before a reaction ensues (17). Irritants in eye area cosmetics and in cosmetics in general belong to the latter category. Though most if not all individuals react to the first exposure to a strong irritant, the capacity to react to mild irritants varies considerably (18). Atopics (individuals who have or have had asthma, hay fever and/or atopic dermatitis) and fair skinned individuals who tan poorly appear to be more vulnerable. Factors such as over-exposure, aggressive cleansing, and adverse environmental conditions are also thought to play a role (17, 18). In the author's view an additional factor may be the additive effect of more than one potential mild irritant in a given formulation. 3. ALLERGENS IN EYE AREA COSMETICS Preservatives, antioxidants, and resins are the principal allergens. Preservatives: Parabens, with few exceptions (vide infra) are common to all eye area products. These esters of parahydroxybenzoic acid are combined not infrequently, with at least one other antimicrobial such as phenyl mercuric acetate, imidazolidinyl urea (Germall 115 ©) or quaternium 15 (Dowicil 200 ©) to insure adequate protection against yeasts, molds, and pseudomonads which are widely distributed in nature.