INTRODUCTION

Cosmetics have been around for centuries. Cosmetics are defined by the Food, Drug and Cosmetic Act as ‘articles intended to be rubbed, poured, sprinkled or sprayed or introduced into or otherwise applied to the human body or any part thereof for cleansing, beautifying, promoting attractiveness, or altering the appearance’ and should not alter the structure or function of the skin. Drugs are defined as ‘articles intended for use in the diagnosis, cure, mitigation, treatment or prevention of disease in man’. Cosmeceuticals are cosmetic products that contain bioactive ingredients with the intent to have a beneficial physiologic effect. There is no legal definition of cosmeceuticals. Cosmeceuticals fit somewhere between cosmetics and drugs. However, even water could be classified as a cosmeceutical given its effects on the hydration of the stratum corneum.

Unfortunately, sometimes the cosmeceutical products intended to enhance beauty can lead to a dermatitis that can be quite unsightly, uncomfortable, annoying and perplexing to the patient and the physician. Contact dermatitis is one of these adverse reactions and can be either irritant or allergic in nature, with the former being more common. Allergic contact dermatitis to cosmetics, personal care products, make-up, body washes, moisturizers, creams, nail, lip and hair care products, and the devices (i.e. sponges, applicators) used to apply them can result in a clinical dermatitis. These reports are well documented in the literature and clinically can appear as a well-demarcated reaction at the location of product application. However, the dermatitis can be ectopic to the location the product is applied through transfer to a more sensitive area such as the face or eyelids. Reports of allergic contact dermatitis to cosmeceuticals are not as frequently reported in the literature as one would expect given their widespread usage. This may be due in part to difficulty in testing these products and the lack of standardized allergens.

VITAMINS

Contact dermatitis to cosmeceutical vitamins such as vitamin A (retinol), vitamin C (ascorbic acid), and vitamin E (tocopherol) has been reported in the literature. Vitamin A and its derivatives such as retinol, retinaldehyde, and retinyl palmitate typically produce an irritant contact dermatitis with dryness and skin irritation. This irritation is an unwanted side effect of retinization of the face, but cannot be avoided if the beneficial collagen regenerative effects are to be experienced. Irritant contact dermatitis can sometimes present identically to allergic contact dermatitis, but vesiculation and facial swelling are never an expected part of early retinization of the face. Allergic contact dermatitis to vitamin A is rare, but can be confirmed by positive patch testing. The vitamin A-containing cream can be closed patch tested ‘as is’, but many times it is impossible to determine which of the many ingredients in the preparation is the culprit. Most large cosmeceutical manufacturers can provide a sample of the vitamin A raw material they use in their formulation for individual ingredient patch testing. The person to contact at the company and the address can be obtained from the Cosmetic Industry On Call brochure published as a joint effort between the American Contact Dermatitis Society (ACDS) and the Personal Care Products Council (PCPC; formerly the Cosmetic, Toiletry, and Fragrance Association). More information can be obtained at the PCPC website at http://www.personalcarecouncil.org.

Vitamin C, also known as ascorbic acid, is another vitamin used topically to reverse signs of aging. It is difficult to formulate because it is easily oxidized to inactive products upon exposure to ultraviolet (UV) radiation or oxygen. Allergic contact dermatitis to topical vitamin C is rare, but irritation can occur due to the low pH effects of the ascorbic acid on the skin. The same discussion regarding closed patch testing and ingredient procurement for vitamin A also applies to vitamin C.

Vitamin E, part of a family of compounds called tocopherols, is a common cause of both irritant and allergic contact dermatitis. Its role as a contact allergen is well documented, thus vitamin E represents the most common cosmeceutical vitamin to cause allergic contact dermatitis. Some of the reports have dealt with allergic reactions experienced to vitamin E found in a line of colored cosmetics manufactured in Europe. It appears that the manufacturer used food grade vitamin E instead of cosmetic grade vitamin E which accounted for the allergic contact dermatitis. Many of the casually reported cases of vitamin E allergy appear to be due to consumers breaking open vitamin E capsules intended for oral consumption and rubbing the oil onto wounds or scars to promote healing. While vitamin E formulated in this manner is safe for human oral consumption, it is not intended for topical application. Cosmetic grade vitamin E properly formulated in a moisturizing cream is rarely allergenic.

HYDROXY ACIDS

Hydroxy acids are a group of chemicals frequently found in cosmeceutical products. Contact dermatitis to alpha hydroxy acids (AHAs), beta hydroxy acids (BHAs), and polyhydroxy acids (PHAs) is typically in the form of irritant contact dermatitis. The larger size of PHAs reduces skin penetration, which also lessens the opportunity for irritant contact dermatitis to occur. More irritant reactions are seen with the AHAs, in the form of stinging and burning due to the low pH of these cosmeceuticals that rapidly penetrate the stratum corneum to reach the nerve endings in the dermis. AHAs that have been partially neutralized produce less contact dermatitis, but also do not produce dramatic antiaging effects. BHAs, such as salicylic acid, are oil soluble and do not penetrate the stratum corneum well. For this reason, irritant contact dermatitis is lessened, but can still occur in patients with compromised barrier function.

BOTANICALS

Botanicals form one of the largest categories of cosmeceutical ingredients in today’s marketplace. Given the push to nature in our increasingly health conscious society, botanicals are often seen by consumers as natural safer alternatives to their synthetic counterparts. As a result of a strong driving force within the cosmetic industry toward natural products, botanicals are a common cosmeceutical active ingredient. Botanical additives are made from various parts of the plant including the leaves, root, fruits, stems, or flowers. The concentration, composition, efficacy, and antigenicity of a given plant extract may differ depending on the part of the plant from which it was obtained. Different antigens may also be present depending on the time of year the botanical was harvested, where the plant originated, and how the plant material was processed prior to incorporation into a cosmeceutical. Therefore the antigenic component of a particular botanical can vary significantly based on these factors.

There are few systematic reviews on the subject of contact dermatitis and botanicals. Although there are many cases of contact dermatitis to botanicals and essential oils in the literature, most cases of allergic reactions that have been documented are single case reports. With the increasing use of botanicals in the cosmetic and cosmeceutical arena, more reactions to these extracts are expected. This section will not review all of the individual case reports of allergic reactions to botanicals; rather it will serve to highlight some of the more common botanical culprits.

Aloe is a commonly used botanical extract for its soothing properties on wounds, burns, and irritated skin (Fig. 21.1). It is a mucilage containing thousands of individual chemical entities. This makes determination of the exact allergen impossible. Yet, case reports of allergic contact dermatitis are found in the literature. Patients who have experienced a suspected allergic contact dermatitis to aloe should simply learn to read ingredient labels and avoid products containing this botanical extract. It is not hard to avoid cosmeceuticals containing aloe.

Fig. 21.1 Aloe vera mucilage is a possible cause of allergic contact dermatitis

Ginkgo biloba is another common botanical used primarily for its anti-inflammatory effects. There have been no reports of allergic contact dermatitis to products containing this botanical documented in the literature.

Tea tree oil or melaleuca oil is derived from the Cheel shrub in Australia (Fig. 21.2). It has gained increasing popularity in a variety of over-the-counter (OTC) products, including antibacterials, antifungals, shampoos, and OTC salon treatment products designed to minimize dandruff or seborrheic dermatitis. Tea tree oil can cause allergic contact dermatitis and in one study was found to be the most allergenic botanical extract. Although there are several antigenic components of this oil, the constituents of the oil thought to cause the majority of allergic reactions are d-limonene and terpinen-4-ol; however, not all patients who react to tea tree oil react to these components.

Fig. 21.2 Homeopathic dandruff shampoos may be a source of tea tree oil exposure

Curcumin is an antioxidant derived from turmeric root. Curcumin is a common additive to Middle Eastern and Indian food as a hot spice. Its use in these cultures dates back to the prerefrigeration era when curcumin was used as a food preservative. It is used in some cosmeceuticals to prevent the product from discoloring or oxidizing on the store shelf. Several currently marketed cosmeceutical moisturizers contain curcumin to prevent the degradation of ceramides added to enhance the skin barrier. Curcumin is a cutaneous irritant and can cause stinging, burning, and itching in patients with atopic dermatitis or other barrier defects. There are also rare reports of allergic contact dermatitis resulting from topical contact with curcumin.