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Allergic contact dermatitis from cosmetics in children and adolescents has recently become more frequently observed and recognized. Fragrances, hair dyes, sunscreen agents, and preservative agents, particularly methylisothiazolinone, are the most frequently reported contact allergens.

Ultraviolet (UV) radiation exposure from the sun and artificial UV sources has been widely acknowledged as the major culprit for skin cancer and premature skin aging. Skin cancers are among the most dangerous (cutaneous malignant melanoma) and the most numerous (basal cell carcinoma, actinic keratosis, and invasive squamous cell carcinoma) of all neoplasms in the Caucasian population worldwide. Using sunscreens has been advocated to efficiently reduce the impact of the UV radiation. Even though the safety of UV filters is clearly addressed in national and international regulations, the safety of sunscreen products and their filters is debated. It is obvious that reducing the filter’s bioavailability to the body is the main focus of retardation strategies. This chapter provides information on the few vehicular penetration retardation strategies that have been researched for sunscreens in recent years.

Sunscreen is a key component in the preventive measures recommended by dermatologists and public health campaigns aimed at reducing sunburn, early skin aging, and skin cancer. To maximize compliance, adverse reactions to sunscreens should be minimized. Although inactive ingredients cause many of these reactions, it is important for dermatologists to be aware of reactions to active ultraviolet filters. There are approximately 120 chemicals that can function as ultraviolet (UV) filters. This review focuses on the 36 most common filters in commercial and historical use. Of these, 16 are approved for use by the US Food and Drug Administration. The benzophenones and dibenzoylmethanes are the most commonly implicated UV filters causing allergic and photoallergic contact dermatitis (PACD) reactions; benzophenone-3 is the leading allergen and photoallergen within this class. When clinically indicated, patch and photopatch testing should be performed to common UV filters.

Hyper-pigmentation is a common skin condition in which increased melanin production results in darker patches of skin. Although hyper-pigmentation is harmless but still mostly people wish to get rid of them because of increasing craze of beautification in India. Topical corticosteroids (TC) application showed quick amelioration of post-inflammatory hyper-pigmentation patches. Prolonged and unsupervised use of TC leads to skin atrophy and reappearance of hyper-pigmentation patches. We present two cases of hyper-pigmentation induced by TC misuse. In case-1, a 20 year old female came to OPD with a complaint of hyper-pigmentation and itch sensation along with drug history of Betnovate cream for the last 2 years for acne treatment. On examination, she showed signs of hyper-pigmentation on cheeks. She was counselled to stop the further use of Betnovate cream and prescribed demelanizing agents along with sunscreen and emollients. The patches improved significantly with above management within 15 days. In case-2, a 33 year old female came to OPD with complaints of redness over whole face, increased facial hair growth and burning sensation along with drug history of using Betnovate cream for 2 years. On examination she showed signs of hyper-pigmentation and redness on cheeks, bruise and tearing of skin and increased facial hair growth. She was counselled to stop the further use of Betnovate cream. She was prescribed retinoic acid cream, sunscreen agents, anti-allergic tablets and emollient cream. The patches improved significantly with above management within 15 days.

Octocrylene is an ultraviolet (UV)B and UVAII absorber that was introduced some 15 years ago, and is now widely used in sunscreen agents and skin care cosmetics. Since 2003, several studies, notably from France, Belgium, Spain, and Italy, have reported an increasing number of patients with photocontact allergy to octocrylene. This reaction is seen mainly in adult patients who have previously used topical products containing the non-steroidal anti-inflammatory drug ketoprofen. Photosensitization to ketoprofen leads, in many cases, to photocontact allergy to octocrylene; the mechanism of this reaction is unknown. Contact allergy to octocrylene also occurs, but is far less frequent, and is seen, in most cases, in children, resulting from the use of octocrylene-containing sunscreen products. In this article, (photo)contact allergy to octocrylene is fully reviewed.

BACKGROUND Photopatch testing is important for diagnosing photoallergic contact dermatitis. Although results of photopatch testing have been presented from many European centers, there have been few reports of the results of photopatch testing in the United States. OBJECTIVE To review the Mayo Clinic's recent experience with photopatch testing, identify common photoallergens, and compare our current and previous findings. METHODS We retrospectively reviewed records of patients who underwent photopatch testing at the Mayo Clinic between January 1, 2000, and December 31, 2005 (N = 182). RESULTS Fifty-four patients (29.7%) had photoallergic contact reactions, and 29 (15.9%) had allergic contact reactions. The most common photoallergens were medications, sunscreen agents, fragrances, and antiseptics. CONCLUSION Photopatch testing is the technique useful in identifying photoallergens. The series of allergens used must be constantly updated to reflect newly identified and outdated photoallergens. We present a 6-year experience with photopatch testing. Medications, sunscreen agents, fragrances, and antiseptics were the most frequently identified photoallergens.

Photoprotection is an effective method for preventing damaging effects from ultraviolet radiation (UVR). Photoprotection is accomplished through the use of sunscreens, protective clothing, and safe sun practices. Sunscreens are composed of various UV filters, including inorganic/physical blockers and organic/chemical sunscreen agents. New technologies are emerging in sunscreen development and may soon be available to U.S. consumers. General guidelines for sunscreen use should be reinforced to improve patient compliance and sunscreen efficacy. Habitual use of sunscreen is recommended with UV exposure, and concerns for vitamin D deficiency with sunscreen use should not supersede proper photoprotective behavior.

The increased awareness of protection against skin cancer has led to a rise in the use of topically applied chemical sunscreen agents. There is a concern about the systemic absorption of organic filters in sunscreen formulations. The present study briefly reviews theoretical models for the prediction of the percutaneous penetration of the organic molecules and the accepted methods for the in vitro and in vivo evaluations of the penetration. The influence of the vehicle and the formulation viscosiy on the penetration of sunscreens are examined. The development of novel methods for the minimization of sunscreen absorption is also discussed. © 2006 Blackwell Publishing.

Synopsis In continuation of a previous spectroscopic and quantum chemical study on 2-acetylindan-1,3-dione (2AID), the spectral properties and photostability of 2AID and its Cu2+ and Zn2+ complexes in different solvents are reported. Comparison is made with the photostability of two commercially available sunscreens: benzophenone-3 and octylmethoxycinnamate. 2AID exhibits a higher photostability, high molar absorption coefficient (42 000 m−1 cm−1) at λmax and broad-spectrum UV-protection properties. The hypothesis that the strong intramolecular H-bonding is responsible for the higher photostability was confirmed by studying the photodegradation upon irradiation with UV light of 2AID in hydrogen bond-breaking solvent, DMSO. The data obtained show that 2AID undergoes rapid degradation in this solvent. It is found that Cu2+ and Zn2+−2AID complexes show higher photostability in DMSO than 2AID itself. Resume A la suite d'une etude prealable en Chimie Spectroscopique et quantique, portant sur le 2-Acetylindan-1,3 dione (2AID), les proprietes spectrales et de photo stabilite du 2AID et ses complexes de Cu2+ et Zn2+ dans differents solvants sont rapportees ici. La comparaison avec la photo stabilite de 2 filtres solaires commerciaux – Benzophenone-3 et l'Octylmethoxycinnamate a ete conduite. Le 2AID montre une photo stabilite superieure, un coefficient d'extinction eleve (42 000 m−1 cm−1) a sa λmax et des proprietes de protection a large spectre. L'hypothese que la forte liaison Hydrogene intramoleculaire est responsable de la plus forte photo stabilite a ete confirmee par l'etude de sa photo degradation sous irradiation UV du 2AID dans un milieu solvant dissociant ces liaisons, le DMSO. Il est montre, de plus, que les complexes de Cu2+ et Zn2+ du 2AID sont plus photo stables dans ce solvant que le 2AID seul.

Synopsis Objective Commercial sunscreens consist of various compounds ranging from inorganic mineral pigments to organic chemical absorbents to achieve the required degree of protection against sunlight. However, the UV radiation screening ingredients have side effects. In this study, therefore, to ensure compliance with the maximum permissible chemical concentrations in sunscreen cosmetic products, a simultaneous and improved determination method for sunscreen chemicals was assessed. Methods Waters 2690 separations module HPLC system equipped with a Waters 486 tunable absorbance detector (UV–visible detector) has been employed and optimized to detect 14 compounds. For the separation, a Waters C18 column (5 μm, 4.6 mm i.d. 150 mm) and 1% of 0.1 M phosphoric acid in ethanol (solvent A) and in distilled water (solvent B) as mobile phases were used. Results The correlation coefficients of 14 standard mixture solutions exceeded 0.9993 in the range 2.5–200 μg mL−1. The intra- and interday recovery and precision (relative standard deviation) of the method were 90.91–109.98% and within 10%, respectively, indicating that the developed method could provide reliable, precise and reproducible data. The detection limit was determined to be 0.01–1.99 μg mL−1, and the quantization limit was determined to be 0.02–6.02 μg mL−1, which were relatively lower than previous studies. Conclusion This method was highly optimized in terms of selectivity, reproducibility and efficiency for the detection of 14 compounds. The validation data indicated that the improved method was quite suitable for their quantitative analysis of commercial product samples. Therefore, this method was applied to the determination of 14 compounds in commercial sunscreen cosmetic products. We verified that the amounts of sunscreen ingredients in the five currently sold sunscreens were >0.5% and within the designated limit, which means those could produce the safe and desired sunscreen effects on the skin. The present method could be applied to effectively monitor the process management and quality control of the cosmetics that are sold in the market. Resume Objectif Les ecrans solaires commerciaux sont constitues de divers composes allant de pigments mineraux inorganiques aux absorbants chimiques organiques pour atteindre le degre de protection necessaire contre la lumiere du soleil. Cependant, les ingredients des filtres UV ont des effets secondaires. Dans cette etude, par consequent, pour assurer la conformite avec les concentrations maximales admissibles de produits chimiques dans les produits cosmetiques du type creme solaire, une methode de determination simultanee et l'amelioration des produits chimiques de protection solaire a ete evaluee. Methodes Le systeme Waters 2690 de separations HPLC equipe d'un detecteur Waters 486 d'absorbance accordable (detecteur UV-visible) a ete employe et optimise pour detecter 14 composes. Pour la separation, une colonne Waters C18 (5 μm, 4.6 mm DI × 150 mm) et 1% de 0.1 M d'acide phosphorique dans de l'ethanol (solvant A) et dans de l'eau distillee (solvant B) en tant que phase mobile, ont ete utilises. Resultats Les coefficients de correlation de 14 solutions de melange standards sont superieurs a 0.9993 dans la gamme 2.5–200 μg mL−1. Les rendements intra- et inter-jour et la precision (ecart type relatif) de la methode etaient de 90.91 a 109.98% et de 10% respectivement, ce qui indique que la methode developpee pourrait fournir des donnees fiables, precises et reproductibles. La limite de detection a ete determinee comme etant 0.01–1.99 μg mL−1, et la limite de quantification est determinee comme etant 0.02–6.02 μg mL−1, qui sont relativement plus bas que les etudes precedentes. Conclusion Cette methode a ete hautement optimise en termes de selectivite, la reproductibilite et d'efficacite pour la detection de 14 composes. Les donnees de validation ont indique que l'amelioration de la methode est tout a fait appropriee pour l'analyse quantitative d'echantillons de produits commerciaux. Par consequent, cette methode a ete appliquee a la determination de 14 composes dans les produits cosmetiques commerciaux de protection solaire. Nous avons verifie que les quantites d'ingredients de protection solaire dans les cinq ecrans solaires actuellement commercialises sont >0.5% et dans la limite designee, ce qui signifie qu'ils peuvent produire des effets de protection solaire surs et souhaites sur la peau. La presente methode pourrait etre appliquee pour surveiller efficacement la gestion des processus et controle de la qualite des produits cosmetiques qui sont vendus sur le marche.

During the aging process, morphological changes in the human skin appear most noticeably in areas of frequent exposure to ultraviolet (UV) light from the sun, such as the face and hands. Chronic UV exposure induces photoaging, characterized by pigmented spots and wrinkles in the skin. Gradual destruction of the ozonosphere has raised photoaging risk. This has led to rapid growth of the anti-photoaging cosmetic market, especially among women with young and fair skin. Sunscreen agents are a first choice for protection against photoaging. However, a certain amount of UV irradiation penetrates skin dermis, and adverse effect may occur with use of these agents. Because of this, a current trend is the development of safer cosmetic ingre‐ dients that effectively inhibit the UV signaling pathways leading to photoaging [1].

To the Editor: Recently 2 very interesting, stimulating articles about sunscreens appeared. The first from Ou-Yang et al reports sun-protection factors (SPFs) of 6 sunscreens, SPF 30 to 100, tested at 4 application rates from 0.5 to 2.0 mg/cm. They suggest that because sunscreen users may apply much less than the prescribed 2 mg/cm, SPFs as high as 100 are valuable because at 0.5 mg/cm at least SPF 30 protection remains. The other by Chouteau et al, testing both sunscreen products and active ingredients, reported that 13 of 21 showed antiinflammatory activity, including, interestingly, all ingredients in the SPF 100 products in the study of Ou-Yang et al. Table I shows sunscreen product amount applied over 0.5, 1, and 2 m body surface areas based on several of the application densities reported by Ou-Yang et al, and the corresponding topically applied amount of potential anti-inflammatory sunscreen agents. Because today’s sunscreen products are very water resistant, applied sunscreen is very efficiently absorbed into the body potentially at levels with pharmacologic significance. The SPF 100 products contained 5 sunscreens comprising 39% of their total weight, over half of which are salicylates, relatives of aspirin, reasonably expected to exhibit some degree of analogous antiinflammatory activity. Following this aspirin analogy, the amount of anti-inflammatory sunscreen agent applied to the skin is comparable to 2.5 to more than 40 tablets, not trivial levels of potent drugs. The sunscreens oxybenzone and dioxybenzone have in fact been patented as anti-inflammatory agents shown to be effective in attenuating ultraviolet-induced erythema when applied following exposure. In addition, several sunscreen agents were also reported as inhibiting the inflammatory mediator, inducible nitric oxide synthase. On the basis of these data, particularly that oxybenzone present in each of the products reported by Ou-Yang et al independently reduces ultraviolet erythema via anti-inflammatory mechanism(s) rather than the inherent optical attenuation of ultraviolet, the conclusions reached by Ou-Yang et al must be reconsidered. Robert M. Sayre, PhD, John C. Dowdy, PhD, and E. William Rosenberg, MD Rapid Precision Testing Laboratories, Cordova; Division of Dermatology, Department of Medicine, University of Tennessee Health Science Center, Memphis; and Department of Physics, University of Memphis

Reports of contact sensitization and photocontact sensitization induced by various sunscreening agents are reviewed. Current knowledge about the most often used sunscreening agents is summarized. The problems of cross-sensitization and sensitization in photodermatoses are discussed. Strategies for patch and photopatch testing, as well as immediate-type testing, are critically evaluated.

The relationship between use of sunscreen and health risk behaviors was evaluated in 175 Israelis aged 17–78 years. No correlation was found between health risk behavior in terms of smoking and alcohol consumption, and use of sunscreen. We found a correlation between age group (under or over 30 years) and the use of sun protection agents, with younger people using them more than older ones. There was no difference in sun protection behavior between smokers and non-smokers, and between alcohol consumers and non-consumers: Both smokers and non-smokers, and alcohol consumers and non-consumers do use sunscreen agents. Hence, our data do not indicate a correlation between health risk behaviors and sun protection behavior.

We report a case of photoallergic contact dermatitis to two sunscreen agents, methoxycinnamate and oxybenzone, occurring in a 6-year-old Asian boy.

Synopsis Sunscreen protection factors, obtained for dilute solutions contained in 2 cm quartz cells placed between a human subject and the Xenon Are sun simulator lamp, are able to be correlated with spectrophotometric data. The correlation, interpreted in terms of the mechanism of sunscreen protection, successfully predicts that an opacifier which is active only in the UV-A spectral region, though ineffective as a sunscreen by itself, would significantly enhance the protective ability of an opacifier which is active mainly in the UV-B spectral region, and that complete erythemal prevention requires opacification to both the UV-B and UV-A regions. This correlation is reached by measuring the total area under the spectral curve in the UV-A and UV-B regions as predicted by a new form of Beer's law, for polychromatic radiation, which is derived. The procedure is shown to be a simple approach to predicting the efficacy of various sunscreen agents which do not exhibit fluorescence.

Aims Topical sunscreens are routinely applied to the skin by a large percentage of the population. This study assessed the extent of absorption of a number of common chemical sunscreen agents into and through human skin following application of commercially available products. Methods Sunscreen products were applied to excised human epidermis in Franz diffusion cells with the amount penetrating into and across the epidermis assessed by h.p.l.c. for 8 h following application. Results All sunscreen agents investigated penetrated into the skin (0.25 g m(-2) or 14% of applied dose), but only benzophenone-3 passed through the skin in significant amounts (0.08 g m(-2) or 10% of the applied dose). With one exception, suncreen agents in corresponding products marketed for adults and children had similar skin penetration profiles. Conclusions Whilst limited absorption across the skin was observed for the majority of the sunscreens tested, benzophenone-3 demonstrated sufficiently high penetration to warrant further investigation of its continued application.

A method for the in vitro determination of low- and high-value sun protection factors (SPF) of sunscreens using artificial substrates and a novel pseudo double beam (PDB) mode of operation of a standard double beam UV spectrophotometer is described. The method allows transmittance to be calculated from detector responses of reference and sample beams measured at different gain levels and facilitates the accurate quantification of low levels of electromagnetic radiation transmitted through highly absorbing samples. The spectrophotometer was modified to hold quartz diffusing plates on which a substrate [Transpore adhesive tape or human stratum corneum obtained from a skin surface biopsy (SSB)] and the sunscreens to be tested were applied. The PDB mode of operation increased the effective linear range of the detector response of the spectrophotometer by a factor of approximately 20000-fold, enabling the in vitro SPF determination technique to be applied to both high and low SPF value sunscreens. Eight commercial sunscreens with known SPF values ranging from 4 to 77, previously determined by in vivo methods, were tested in vitro using both test substrates and correlations between the in vivo and in vitro values were determined. SPF values determined using the in vitro method correlated well with the known in vivo results (Transpore tape, R(2) = 0.611; SSB, R(2) = 0.7928). The in vitro SPF obtained for one of the tested products differed substantially from the cited in vivo SPF value. Independent in vitro and in vivo re-evaluation of the SPF of this product matched the value predicted by the present method much more closely than the originally cited in vivo value. All determined SPFs were ordered correctly in comparison to in vivo ranking and the technique appeared to correctly identify a sunscreen that had a labelled SPF value that was significantly higher than its true SPF.

Purpose: To determine whether photoallergic contact dermatitis is as uncommon as it is usually considered to be and to review the associated clinical features. Methods: We reviewed the literature on photoallergic reactions induced by the topical contact of the skin with a chemical in the presence of, or followed by, exposure to UV or visible light. Some of the more recently observed photo-allergens and those presenting special clinical features are discussed. Results: The literature cites several topical substances that give rise to photoallergic contact dermatitis, some of them only exceptionally but others quite frequently. The clinical features are not always those of a eczematous eruption, and several parts of the body may be affected. Conclusions: Many topical photoallergic culprits have been reported in the literature, the most important of which are sunscreen agents and, recently, non-steroidal anti-inflammatory agents (NSAIDs). Not at all exceptional is the occurrence of photoaggravation and recurrent transient or even persistent light reactions on previously exposed as well as non-exposed areas (often sparing the original application site), particularly with the NSAID ketoprofen. Moreover, cross-reactions with chemically-related as well as non-chemically related molecules are common. The potentially misleading clinical features observed in some cases, the diversity of the casual substances identified, and the low frequency with which photopatch testing is carried out in general indicate that the occurrence of photoallergic contact dermatitis might well be underestimated.

Methylene bis-benzotriazolyl tetramethyl butylphenol and bis-ethylhexyloxy phenol methoxyphenyl triazine are sunscreen agents that have hydrophobic behaviors in common. They were not normally assayed with the following four sunscreen agents that have hydrophilic behaviors in a single chromatographic run: ethylhexyl methoxycinnamate, isoamyl p-methoxycinnamate, ethylhexyl salicylate, and ethylhexyl triazone. For that reason, methylene bis-benzotriazolyl tetramethyl butylphenol and bis-ethylhexyloxy phenol methoxyphenyl triazine require much time in order to assay products with those materials. A rapid, selective, and reproducible determination method needs to be developed for the simultaneous examination of methylene bis-benzotriazolyl tetramethyl butylphenol and bis-ethylhexyloxy phenol methoxyphenyl triazine with the sunscreen agents, ethylhexyl methoxycinnamate, isoamyl p-methoxycinnamate, ethylhexyl salicylate, and ethylhexyl triazone. This new technique could reduce time in examining the sunscreen agents and be effective for quality control of suncare products. In this paper, the HPLC and UPLC system is used for developing the determination of the sunscreen agents. Several evaluations of some mixtures of eluents and columns were obtained for the optimal condition of separation. In HPLC, the optimal peak resolution was obtained through ethanol-water gradient elution and a 75-mm C18 column with a 3.5-microm-sized particle on a flow rate of 1.0 ml/min. In UPLC, the most distinctive peak resolution was obtained through methanol-water gradient elution and a 50-mm C18 column with a 1.7-microm-sized particle on a flow rate 0.4 ml/min. Both of those chromatographic determination methods could be used in the examination of six types of sunscreen agents without any interference from other product excipients in the agents. The proposed determination methods were validated for specificity, linearity, repeatability, system stability, intermediate precision, and accuracy. Consequently, HPLC and UPLC determination methods could be rapid, selective, and proper applications for the assay of sunscreen agents in suncare products.

This study was conducted to investigate in vivo evaluation of protectiveness by sunscreens in the UVA range using a mouse model of contact photoallergy (CPS) to 3,3′,4′,5-tetrachlorosalicylanilide (TCSA). Mice were sensitized with TCSA painting plus UVA irradiation (TCSA/UVA) on the abdomen and, 5 days later, challenged with TCSA/UVA on the earlobe. Each of four sunscreen agents, benzophenone-3, Parsol 1789, p -aminobenzoic acid, and 2-ethyl-hexyl- p -methoxycinnamate, was applied to the earlobes before irradiation. Their protective efficacy was evaluated in the degree of inhibition of both ear swelling responses and TCSA-epidermal cell photoadduct formation. Two UVA-absorbing sunscreens, benzophenone-3 and Parsol 1789, dramatically inhibited the ear swelling response, while the two UVB-absorbers exhibited a much less suppressive effect. The UVA-absorbing agents functioned via inhibiting the formation of TCSA-epidermal cell photoadducts. This method is thought to be useful for in vivo estimation of UVA protection provided by sunscreens against the exquisite sensitivity involved in photoallergy.

This paper was presented as a poster in the Industrial Pharmacy section at the International Pharmaceutical Federation (FIP) Congress, Cairo, 2005. Synopsis The purpose of this study was the development of a microbiological method for the assessment of the ultraviolet (UV) screening effect of sunscreen preparations and determination of their sun protection factor. The method is based on the lethal effect of UV radiation on Escherichia coli and the protective ability of sunscreens. The time of UV exposure required for the reduction of the E. coli viable count by 90% (decimal reduction time, DRT) was used as the photoprotection assessment parameter. The method was tested by assessing the effect of selected experimental variables on the DRT. The suitability of the method as a quality control tool for sunscreen preparations was then checked by assessing the influence of selected formulation variables on the photoprotective effect of a series of o/w emulsion formulations with different compositions. The method proved valid for detecting changes in the photoprotective effect of a market sunscreen product as a result of modifying experimental conditions. It also proved valid for ranking market sunscreen products according to their UV screening effect. Equally important, the method could successfully detect changes in the photoprotective effect of sunscreen test formulations as a function of the concentration and type of the sunscreen agents.

Photoprotective effect of topically applied superoxide dismutase (SOD) to guinea pig skin was compared with a commercially available sunscreen agent after a single exposure to UVB. While cutaneous SOD activity was remarkably decrease in non-treated control animals, both topical SOD and sunscreen agent significantly reduced the decrease in skin SOD activity after UVB irradiation. However, only the sunscreen agent successfully reduced erythema reaction 24h after irradiation but topical SOD failed. These findings suggest that topical SOD protects skin from photo-oxidative damage without affecting erythema response, and thus, from a practical standpoint, sunscreen agents, when compared with topical antioxidants, seem better at present for daily photoprotection.

The non-steroidal anti-inflammatory drug ketoprofen is widely used for topical treatment. In Sweden, ketoprofen has been available for topical application since 1995. Photoallergic contact dermatitis from ketoprofen-containing topical preparations usually includes severe eczematous reactions. Ketoprofen is derived from propionic acid, and it is also a substituted benzophenone and therefore structurally similar to fenofibrate and sunscreen agents based on benzophenones. During the last 2 years, 35 patients have been refereed to our department with suspected photoallergic or allergic reactions after having used ketoprofen-containing gels. Photopatch testing with the photopatch standard series, the ketoprofen-containing gels and their ingredients, fenofibrate, benzophenone-3, benzophenone-10 and benzophenone-4, was performed. Photoallergic reactions to ketoprofen were noted in 35 patients and a simultaneous contact allergy to ketoprofen in 2 patients. Simultaneous photoallergy to fentichlor, tetrachlorosalicylanilide and fenofibrate was registered in 74%, 40% and 73% of the patients, respectively.

The patients sensitised to sunscreen agents who attended our Contact Dermatitis Clinic between February 1985 to March 1987 have been reviewed. 15 (5%) of 280 patients tested with sunscreens had positive reactions; 3 of them were allergic to more than one agent. The most frequent contact allergens were hydroxy methoxy methyl benzophenone (Mexenone) [6], followed by isopropyl dibenzoylmethane (Eusolex 8020/8021) [5], octyl dimethyl para-aminobenzoate (Escalol 507) [2], and one reaction each to butyl methoxy dibenzoylmethane (Parsol 1789), amyl dimethyl para-aminobenzoate (Escalol 506), and ethoxy ethyl-p-methoxy cinnamate (Givtan F). Positive photopatch tests were seen with isopropyl dibenzoylmethane, butyl methoxy dibenzoylmethane, para-aminobenzoate (PABA) and ethoxy ethyl-p-methoxy cinnamate, one reaction each.

Summary The derivatives of paraaminobenzoic acid listed by the council of Europe (February 1981) as 'Sunscreen agents used to protect the skin'can be determined by simple chromatographie methods (TLC + GLC) described in a previous article. In Amerscreen (R)-P*, (trade name of N-propoxylated ethyl paraaminobenzoate), four constituants are identified by means of nuclear magnetic resonance spectroscopy (NMR) and quantitatively measured by high pressure liquid chromatography (HPLC) in sun-creams.

Sunscreen preparations containing various chemical UV absorbers, para-aminobenzoic acid (PABA), 2 PABA derivatives, benzophenone or a combination of these were topically applied to the backs of C3H/HeN mice prior to their being irradiated with ultraviolet light in the UVB range. In all cases this treatment was effective in preventing the pathological skin changes associated with UVB irradiation. Histological evaluation of skin biopsies from mice treated with the sunscreen preparations and UVB irradiation showed little or no difference from normals in amount of hyperplasia, melanization or parakeratosis present. These histologic changes were observed in animals receiving UVB irradation in the absence of any sunscreen agent. Pretreatment with the various sunscreen agents did not, however, prevent the induction of tumor susceptibility as measured by the sustained growth of a UV-induced tumor which is immunologically rejected in normal syngeneic mice. These data show a clear distinction between the effects of UVB irradiation leading to histological changes in the epidermis and those leading to the state of tumor susceptibility in mice. The distinction was further corroborated by the finding that epidermal hyperplasia induced by repeated applications of croton oil had no significant enhancing or inducing effects on the induction of tumor susceptibility. In addition, the induction of tumor susceptibility. In addition, the induction of tumor susceptiblity is not due to wavelengths of light less than 320 nm since this effect was abrogated when the UVB radiation was filtered through glass. Possible mechanistic differences between the tumor susceptiblity generated in UVB and photoprotected UVB irradiated animals were observed, however, when we attempted to adoptively transfer the state of tumor susceptibility to normal animals. While it was readily transferable with splenic lymphoid cells from UVB irradiated animals, all attempts to transfer the tumor susceptibility from photoprotected animals have, to date, been unsuccessful.

IN ADDITION to the rays of the visible spectrum, sunlight contains rays of shorter wave length, those of the ultraviolet range. Coblentz and his associates 1 confirmed earlier work of Hausser and Vahle, and of Luckiesh, Holladay, and Taylor, establishing the fact that a maximal burn or erythemogenic effect in the skin was obtained per unit of energy absorbed at a wave length of 2,970 A. Another erythemogenic effect is obtained with rays of wave length 2,400 to 2,500 A. Rays with wave lengths ranging from 3,200 to 3,650 A. will "tan" (cause pigmentation) but not produce a burn. Sunscreen agents are products which upon topical application absorb or otherwise prevent actinic, erythemogenic rays of the sun from reaching the sensitive skin. Ideally, a sunscreen should permit the rays of the longer ultraviolet range responsible for "tanning" (pigmentation) to reach the skin. Many chemical compounds have been found capable of