Contact allergy to oxidised geraniol may be over-represented in individuals with photocontact allergy to ketoprofen.

BACKGROUND: Simultaneous overrepresentations of contact allergies and photocontact allergies are common in individuals with photocontact allergy to ketoprofen. AIMS: To investigate whether contact allergy to oxidised (ox.) geraniol, geraniol, geranial, neral and citral is overrepresented in individuals with photocontact allergy to ketoprofen. METHODS: The contact allergy rates to ox. geraniol, geraniol, geranial, neral and citral in routinely patch tested dermatitis patients were compared with the corresponding rates in individuals with photocontact allergy to ketoprofen. RESULTS: Allergic patch test reactions were noted to ox. geraniol 11% (n = 39, 5.8%), ox. geraniol 6% (n = 12, 1.8%), geraniol 6% (n = 2, 0.3%), geranial (n = 18, 2.7%), neral (n = 7, 1.0%) and citral (n = 15, 2.2%). In those four patients who were diagnosed with photocontact allergy to ketoprofen during the test period, a significant overrepresentation (p = 0.020) of simultaneous contact allergy to ox. geraniol 11% was demonstrated. Overrepresentation of simultaneous contact allergy to various combinations of ox. geraniol, ox. limonene and ox. linalool was also noted in ketoprofen-photoallergic patients. CONCLUSIONS: Contact allergy to ox. geraniol, geranial and citral is common in routinely tested dermatitis patients. There is an overrepresentation of simultaneous contact allergy to ox. geraniol, ox. limonene and ox. linalool in patients with photocontact allergy to ketoprofen.

Photopatch testing in Singapore: A 10-year retrospective study.

BACKGROUND: Photopatch testing represents the gold standard for the diagnosis of photoallergic contact dermatitis (PACD). We aimed to identify common photoallergens in our tertiary dermatological referral centre from 2012 to 2021, to compare this to the preceding period studied, and data from other communities. METHODS: We conducted a retrospective review of all 90 patients who underwent photopatch testing at the National Skin Centre, Singapore, between 2012 and 2021. RESULTS: Of 90 patients, 19 (21.1%) were male, and the mean age was 41.6 years. Eighty-four (93.3%) underwent testing to our standard sunscreen series, 10 (11.1%) to our extended series, and 73 (81.1%) to their own items. Seventeen (18.9%) were diagnosed with PACD (i.e., photocontact allergy with present or past relevance), 12 (13.3%) with ACD, and 4 (4.4%) with photoaugmented ACD. Relevant reactions were commonest to oxybenzone (8, 9.5%) and mexenone (3, 3.6%). Eleven (15.1%) had PACD to their own items, with 3 of 4 (75%) tested to ketoprofen diagnosed with PACD and the remaining 1 (25%) with photoaugmented ACD. Age, race, sex, atopy, and site of involvement were not associated with photocontact allergy. Compared to the preceding time period, the overall frequency of photocontact allergy and PACD decreased, but rates of photoallergic reactions to individual photoallergens were not significantly different. CONCLUSION: Organic ultraviolet absorbers such as oxybenzone and mexenone remained the most relevant photoallergens. Personal item testing was valuable, and testing to ketoprofen should be considered.

Dermal Safety of Tapinarof Cream 1%: Results From 4 Phase 1 Trials.

BACKGROUND: Tapinarof (VTAMA®; Dermavant Sciences, Inc.) is a novel, non-steroidal, topical, aryl hydrocarbon receptor agonist, FDA approved for psoriasis treatment and under investigation for atopic dermatitis treatment as a 1% cream formulation for once-daily (QD) application. OBJECTIVE: Evaluate cumulative skin irritation, sensitization, and photoallergic and phototoxic potential of tapinarof cream 1% across a range of dosing frequencies and conditions. METHODS: We conducted 4 randomized, controlled, phase 1 trials of topical tapinarof cream 1% vs vehicle or other appropriate controls in healthy adults. Cumulative skin irritation was assessed following QD application for 21 days under fully occlusive patch conditions. Contact sensitization, photoallergenicity, and phototoxicity were assessed under semi-occlusive patch conditions. The contact sensitization and photoallergenicity trials used an induction phase of repeated applications followed by a 2-week rest period and a 1-time challenge, with rechallenge if responses indicated sensitization/photosensitization; the phototoxicity trial comprised a single application. Ultraviolet A and B irradiation was used to assess photoallergenicity/toxicity. RESULTS: 376 participants were randomized across the 4 trials. In the cumulative irritation trial, tapinarof cream 1% QD was classified as having a slight potential for very mild cumulative irritation under the exaggerated test conditions of repeated dosing for 21 days. There was no evidence of sensitization, photosensitization, or phototoxicity. Tapinarof was well tolerated and there was a low discontinuation rate across all trials. CONCLUSIONS: Tapinarof cream 1% was well tolerated, non-sensitizing, non-phototoxic, and non-photoallergic, with no evidence of clinically meaningful cumulative skin irritation in 4 dermal safety trials in healthy adults. TRIAL REGISTRATION: IND 104601 J Drugs Dermatol. 2022;21(10):1084-1090. doi:10.36849/JDD.6627R1.

Contact allergy to fragrance mix I and its components in individuals with photocontact allergy to ketoprofen.

BACKGROUND: Contact allergy to fragrance mix I (FM I) is over-represented in patients photoallergic to ketoprofen. The prevalence of contact allergy to two components of FM I, cinnamal and cinnamyl alcohol, in ketoprofen-photoallergic patients is higher than in dermatitis patients. OBJECTIVE: To explore the prevalence of contact allergy to FM I and its individual components in patients with photocontact allergy to ketoprofen, and to compare with a dermatitis and the general population. METHODS: Data on patch and photopatch tests performed between 2009-2018 were collected. Ketoprofen-photoallergic patients were compared with dermatitis patients and published data on the general population regarding the prevalence and the distribution of contact allergy to FM I and its components. RESULTS: A higher prevalence of contact allergy to cinnamyl alcohol compared with cinnamal (23.3% vs 10.0%), and eugenol compared with isoeugenol (23.3% vs 6.7%), was observed in ketoprofen-photoallergic patients, while the relationship was the opposite in the dermatitis group (0.7% vs 1.05%; 0.4% vs 0.9%). The overall prevalence of contact allergy to several components of FM I was significantly higher in ketoprofen-photoallergic patients. CONCLUSIONS: Contact allergy to FM I and many of its components is over-represented in patients photoallergic to ketoprofen compared with dermatitis patients and the general population.

Contact Allergy to Oxidized Linalool and Oxidized Limonene is Over-represented in Individuals with Photocontact Allergy to Ketoprofen.

Simultaneous contact allergies are common in individuals with photocontact allergy to ketoprofen. The rate of contact allergy to the fragrance substances oxidized linalool and oxidized limonene in ketoprofen-photo-allergic individuals were investigated in comparison with the corresponding rates in individuals without photo-contact allergy to ketoprofen, using Fisher's exact test. A total of 4,021 patients were routinely tested with oxidized linalool; of whom 190 (4.7%) tested positively. For oxidized limonene the numbers were 3,797 patients and 111 positive reactions (2.9%). A total of 19 contact allergic reactions to oxidized linalool were noted in 29 patients (65.5%) who also had photocontact allergy to ketoprofen (p < 0.0001). The corresponding figures for oxidized limonene were 10 positive reactions in 24 ketoprofen-photoallergic individuals (41.7%) (p < 0.0001). Contact allergy to oxidized linalool and/or oxidized limonene is common in routinely tested patients with dermatitis and, particularly, in those patients who are photoallergic to ketoprofen.

Standard photopatch test battery? Proposal based on current epidemiology and experience in our Skin Allergy Unit.

BACKGROUND: The diagnosis of photoallergic contact dermatitis (PACD) is confirmed by photopatch testing (PPT). In Spain, the latest recommendation on which allergens to test in PPT dates from 1995. METHODS: In the last 4 years, we studied 455 patients with epicutaneous tests and performed PPT on 33 of those patients (7.3%). RESULTS: The most prevalent allergens in PPT were as follows: non-steroidal anti-inflammatory drugs (NSAIDs) (46%), fragrances (21%), and solar filters (18%). DISCUSSION: In our country, the most common photoallergens continue to be NSAIDs (ketoprofen). The increasingly common use of sunscreens has led to a growing involvement of solar filters in PACD, which can be also contained in other cosmetics. In our experience, PACD due to fragrances is nonetheless at least similar in frequency. CONCLUSIONS: The PPT battery must adapt to the prescription, use, and exposure habits of each country. We propose a diagnostic model to guide which allergens to test in PPT, which in our experience should also include fragrances.

Photopatch testing in Chinese patients: A 5-year experience.

BACKGROUND: In 2015, a Chinese expert consensus on photopatch testing (PPT) was established, based on European consensus methodology. OBJECTIVES: To update current information on the prevalence of photoallergic contact dermatitis (PACD) to 20 photoallergens and their clinical relevance in the Chinese context. METHODS: A retrospective analysis of 2372 patients who performed PPT in a tertiary referral center in China between 2015 and 2019 was completed. A total of 1208 PACD reactions were observed in 897 (37.8%) patients, and 413 reactions were of current or past relevance. RESULTS: The proportion of reactions of current or past relevance was 34.2%. The most frequent photoallergens were chlorpromazine, thimerosal, potassium dichromate, and formaldehyde. The ultraviolet absorbers, benzophenone and Para-aminobenzoic acid, showed opposite gender distribution to PACD. Twenty-five patients (1.9%) developed PACD reactions to a newly added photoallergen preparation - fragrance mix I. Patients with chronic actinic dermatitis, widespread exposed-site or generalized dermatitis, and older age were more likely to have PACD. CONCLUSIONS: This study is the first to profile PACD reactions with clinical relevance in China. The prevalence of PACD to culprit photoallergens was affected by regional peculiarities. Attention needs to be paid to the age, body-site distribution, and known diagnoses of patients for the identification of PACD.

Photopatch testing in a tropical country, Thailand: 20 years' experience.

BACKGROUND: Photoallergic contact dermatitis is one of the important parts of photodermatoses. The investigation of choice is photopatch testing. However, reports with photopatch test results from Asian countries are scarce. The objective of this study was to determine the prevalence of positive photopatch test reactions and to ascertain the common photoallergens among Thai patients during 1998-2018. METHODS: We retrospectively reviewed the records of 339 patients who were clinically suspected of having photoallergic contact dermatitis and had undergone photopatch testing. RESULTS: A total of 44 photoallergic contact reactions in 38 patients (11.2%) were found. The positive photoallergic reactions were mainly found with organic ultraviolet filters and fragrances. CONCLUSIONS: Organic ultraviolet filter chemicals especially benzophenone-3 and fragrances were found to have a high prevalence of photoallergic contact reactions. Monitoring of the photoallergens employed in photopatch tests should be conducted periodically to provide the best patient care.

Chronic Actinic Dermatitis Revisited.

BACKGROUND: Chronic actinic dermatitis (CAD) is a persistent eczematous photodermatitis classically described in older, white men with contact allergy to plants. However, evidence from recent studies suggests that some demographics of CAD patients may be changing. OBJECTIVE: The aims of the study were to determine the frequency of CAD in patients presenting with photosensitive eruptions and to identify the allergens and photoallergens most closely associated with this condition. METHODS: We identified all patients with a diagnosis of CAD from 246 consecutive records of patients undergoing photopatch testing from July 1994 to June 2018 and summarized the demographics and test results in comparison with non-CAD patients. CONCLUSIONS: Nineteen (7.7%) of the 246 patients evaluated had CAD with a male-to-female ratio of 1:1.7 among CAD patients. Compared with non-CAD patients, photocontact allergy and/or contact allergy to sesquiterpene lactone mix and contact allergy to fragrances were significantly more common in CAD. Contact allergy to p-phenylenediamine was also common. The results of this study suggest that CAD presents in a broader demographic range, including both men and women of both light and dark skin types. Phototesting and photopatch testing should be considered when patients present with clinical findings consistent with CAD.

Topical minocycline foam 4%: Results of four phase 1 studies evaluating the potential for phototoxicity, photoallergy, sensitization, and cumulative irritation.

FMX101 4% contains 4% micronized minocycline (as an HCl) formulated in a lipophilic foam vehicle for topical administration. FMX101 4% has been shown to be an effective and well-tolerated treatment for moderate-to-severe acne in three Phase 3 pivotal studies, however, skin sensitization and toxicity potential remains to be fully evaluated. Four single-center, randomized, controlled, within-subject comparison studies were conducted to evaluate the potential for phototoxicity, photoallergy, skin sensitization, and cumulative skin irritation with topical administration of FMX101 4% and the corresponding vehicle. Across the four studies, healthy male and non-pregnant female volunteers (age ≥18 years) were randomized to FMX101 4%, vehicle, or other controls. In the phototoxicity study, treated skin was irradiated at 3 and 24 hr post-application, and local tolerability was assessed pre- and post-irradiation. In the photoallergy study, the skin was treated and irradiated (post-24 hr) twice weekly for 3 wk (induction phase), rested for 10-17 d, and naive skin sites were treated and irradiated (challenge phase); skin reactions were assessed after patch removal and post-irradiation. In the sensitization study, the skin was treated for 3 wk (induction phase), then rested for 10-14 d, and naive skin sites were treated for 48 hr (challenge phase); contact sensitization was assessed for both phases. In the cumulative irritation study, treatment and vehicle were applied daily for 21 d; skin irritation was assessed after each application. In all studies, standard safety assessments were conducted. A total of 32, 56, 233, and 42 subjects were enrolled in the phototoxicity, photoallergy, sensitization, and skin irritation studies, respectively. There was no evidence of phototoxicity, photoallergy, skin sensitization, or skin irritation potential with FMX101 4%. Few adverse events, mostly mild to moderate, were reported. In conclusion, FMX101 4% appeared to be well tolerated and non-irritating, and was considered to be non-sensitizing, non-phototoxic, and non-photoallergic.

Photodermatoses in skin of colour.

Photodermatoses represent a heterogeneous collection of disorders unified by the characteristic of being provoked through exposure to ultraviolet radiation. Generally, these conditions are classified into the following categories: immunologically mediated photodermatoses, chemical- and drug-induced photosensitivity, photoaggravated dermatoses and photosensitivity associated with defective DNA repair mechanisms or chromosomal instabilities. The list of photodermatoses is extensive, and each individual photodermatosis is understood to a different extent. Regardless, there exists a paucity of information with regards to the clinical presentation among those with skin of colour. With ever-changing global demographics, recognition of photosensitive disorders in a diverse population is essential for accurate diagnoses and therapeutic guidance. The scope of this article seeks to review the epidemiology and clinical variability in presentation of such photodermatoses in patients with skin of colour.

Photoallergic Contact Dermatitis to Sunscreens Containing Oxybenzone in La Plata, Argentina. / Dermatitis por contacto fotoalérgica a protectores solares con oxibenzona en La Plata, Argentina.

BACKGROUND: Photoallergic contact dermatitis (PACD) to oxybenzone was reported for the first time in 1980. Oxybenzone is the most common photoallergen in the United States and Canada and the fourth most common .in Europe. There are no studies or data on the prevalence of oxybenzone PACD in Argentina. OBJECTIVE: To determine the proportion of photosensitive patients with PACD to oxybenzone. METHODS: We conducted a descriptive cross-sectional study of 35 patients with photosensitivity reactions confirmed by photopatch testing at the Research Center of Hospital Público San Martín in La Plata, Argentina, in 2015 and 2016. RESULTS: PACD was identified in 6 patients (17.14%). Five of these (14.28%) had at least one positive reaction to oxybenzone in the photopatch test; 4 had a reaction at irradiated sites only (5 J/cm2 UVA) and one had a reaction at both irradiated and nonirradiated sites. CONCLUSIONS: PACD to sunscreens containing oxybenzone is common and is probably underdiagnosed due to a lack of confirmation by photopatch tests or other diagnostic tools. Sensitization rates vary according to region and are influenced by sunscreen ingredients and variations in the use of sunscreen products, cosmetics, and topical drugs.

Comparison of Demographic and Photobiological Features of Chronic Actinic Dermatitis in Patients With Lighter vs Darker Skin Types.

Importance: Chronic actinic dermatitis (CAD) is classically described in older, white men, although increasing reports describe younger patients with darker skin types, particularly South Asians. Photocontact allergy occurs in CAD but is less studied than contact allergy in this exquisitely photosensitive condition. Objective: To evaluate for differences in demographic and photobiological features between persons with darker and lighter skin types who have CAD. Design, Setting, and Participants: This retrospective review included 70 consecutive adult patients (≥18 years) undergoing investigation for photosensitivity who were diagnosed with CAD from November 1, 2000, through August 31, 2015, at the specialist Photobiology Unit of a tertiary academic referral center. Main Outcomes and Measures: Patient age, sex, ethnicity, clinical features, and phototesting outcomes. Results: A total of 70 patients (37 men [53%] and 33 women [47%]; mean [SD] age, 50.9 [2.3] years) were diagnosed with CAD. Of these, 36 were non-Hispanic and non-Latino white, 31 were Asian (including 24 South Asian, 4 East Asian, and 3 Middle Eastern), and 3 were black. Patients were aged 9 to 83 years at diagnosis, with a mean (SD) age at onset of 42.6 (2.4) years and duration of disease of 8.8 (1.3) years. Forty-one had lighter skin types (Fitzpatrick skin types I-IV), and 29 had darker skin types (Fitzpatrick skin types V and VI). Patients with darker skin types and CAD were younger at diagnosis (mean [SD] age, 40.7 [3.5] vs 58.1 [2.5] years; P < . 001) and had earlier onset of photosensitivity (mean [SD] age, 35.5 [3.9] vs 47.5 [2.9] years; P = .01) compared with patients with lighter skin types. Of note, the male to female ratio in the lighter skin group was 2:1 compared with 1:2 in the darker skin group. Phototest reactions were equally severe in Fitzpatrick skin types V to VI and I to IV, with minimal erythemal doses to monochromatic UV-B, UV-A, and visible radiation and broadband provocation testing showing similar results. Photoallergic contact reactions to UV filters, personal sunscreen products, and nonsteroidal anti-inflammatory drugs were seen in both groups; 14 of 61 patients (23%) undergoing photopatch testing showed positive photopatch reactions. Conclusions and Relevance: Chronic actinic dermatitis presents with an earlier age at onset and an inverted male to female ratio in patients with darker compared with lighter skin types. Clinicians should thus be cognizant of CAD in younger women with darker skin types. Photopatch testing should be considered in patients with CAD, with coexistent photocontact allergy occurring in a substantial proportion.

Photopatch Testing in Chinese Patients Over 10 Years.

BACKGROUND: Photoallergic contact dermatitis (PACD) is a hypersensitivity reaction that occurs when a previously photosensitized exogenous agent comes into contact with UV radiation. The best method for testing PACD is photopatch testing (PPT). OBJECTIVES: The primary objective of the study was to determine the frequency of PACD to 20 different photoallergens in common usage in China during a 10-year period. METHODS: All patients (n = 6153) who had PPTs done between 2005 and 2014 at the Department of Dermatology of Huashan Hospital, Fudan University, were included. RESULTS: A total of 3767 PACD reactions in 3668 subjects (59.61%) were recorded. Of these allergens, chlorpromazine (CPZ) (51.82%), para-aminobenzoic acid (11.94%), thimerosal (9.81%), potassium dichromate (6.37%), sulfanilamide (5.38%), and formaldehyde (4.7%) were the top 6 allergens that elicited PACD reactions. A comparison of PACD reactions between January 2005 to December 2009 and January 2010 to December 2014 revealed a statistically significant decrease in PACD reaction for chlorpromazine, potassium dichromate, p-aminobenzoic acid, and p-phenylenediamine. Formaldehyde showed a trend toward a statistically significant increase in sensitization over the 10-year period. CONCLUSIONS: In conclusion, positive PACD reactions were most frequent to chlorpromazine in our population. New allergens such as potassium dichromate and formaldehyde should be added to the test series.

Molecular mechanisms of drug photodegradation and photosensitization.

Drug-induced photosensitivity of the skin is drawing increasing attention. In past few decades, photosensitivity has been reported with an array of drugs, and is now recognized as a noteworthy medical problem by clinicians, regulatory authorities and pharmaceutical industry. The photosensitivity is of two types i.e., phototoxicity and photoallergy. Phototoxic disorders have a high incidence, whereas photoallergic reactions are much less frequent in human population. Several hundred substances, chemicals, or drugs may invoke phototoxic and photoallergic reactions. In order to avoid photosensitive reactions, it is essential to understand the mechanism behind the photosensitizing properties of such substances before these drugs are introduced in clinical settings. Photosensitization is inter-related to photochemical reaction, through the knowledge of which the photosensitivity of a drug can be anticipated. This review highlights the current research status on photosensitizing drugs and its correlation to phototoxicity. Different mechanisms of photodegradation of photolabile drugs have also been discussed.

Photosensitive disorders of the skin with ocular involvement.

Patients with photosensitive disorders of the skin may present with ocular manifestations that are evident at birth or may be manifested later with progression of the disorder. Dermatologists should be able to recognize these and appropriately refer patients for further management. Ocular involvement associated with immunologically mediated photodermatoses, drug- and chemical-induced photosensitivity, photodermatoses associated with defective DNA repair/chromosome instability, and photoaggravated dermatoses are reviewed. Photodermatoses are commonly classified into four general groups: (1) immunologically mediated photodermatoses; (2) drug- and chemical-induced photosensitivity; (3) photodermatoses associated with defective DNA repair/chromosome instability; and (4) photoaggravated dermatoses. Photodermatoses in these groups with ocular involvement will be discussed. In addition, skin diseases associated with photophobia are also described.

Adverse reactions to sunscreen agents: epidemiology, responsible irritants and allergens, clinical characteristics, and management.

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.

Phytodermatitis in eastern Turkey: a retrospective, observational study.

BACKGROUND: Plant life is extremely diverse, with a great deal of geographic and seasonal variation. Consequently, the range of reported adverse reactions is large, and there are important differences worldwide in the incidence and prevalence of these reactions. Systemic ingestion of some plants containing furocoumarins can cause erythema, edema, vesicle and bulla formation and later hyperpigmentation, after exposure to sunlight. They may at times exhibit clinical manifestations that mimic angioedema, and rarely progress to necrosis. This condition is named phyto-phototoxic reaction. OBJECTIVE: Our aim was to identify plant dermatitis such as allergic contact dermatitis, irritant contact dermatitis, and phyto-phototoxic dermatitis in eastern Turkey and to add new data to the literature. METHODS: Thirty patients diagnosed with plant dermatitis were evaluated retrospectively. The demographic and clinical characteristics of the patients (age, gender, the type of dermatitis, and the name of the causative plant) were recorded. CONCLUSIONS: A phyto-phototoxic reaction to Chenopodium album (Chenopodiaceae) developed in 12 cases. Irritant contact dermatitis developed due to Ranunculus kotschyi (Ranunculaceae) in 11 cases. The other plants studied were Malva neglecta Wallr (Malvaceae), Mandragora autumnalis (Solanaceae), Eryngium billardieri (Apiaceae), Ceratocephalus falcatus (Ranunculaceae), Ranunculus damascenus (Ranunculaceae), and Plantago lanceolata (Plantaginaceae).

Severe skin toxicity in pediatric oncology patients treated with voriconazole and concomitant methotrexate.

We report the occurrence of skin toxicities in pediatric oncology patients on concomitant treatment with voriconazole and methotrexate (MTX). Of 23 patients who received this combination, 11 patients suffered from cheilitis and/or photosensitivity. In contrast, only in 1 of 9 patients who received voriconazole without MTX was photosensitivity observed. A mechanism of action was not able to be identified. We describe two cases with severe skin toxicities. Caution is warranted when using voriconazole and concomitant MTX.

Allergic and photoallergic contact dermatitis: a 10-year experience.

BACKGROUND: Photoallergic contact dermatitis (PACD) is a hypersensitivity reaction that occurs when a previously photosensitized exogenous agent comes into contact with UV radiation. Currently, there are no studies profiling photoallergic reactions in Canada. Because the photoallergen profile changes over time, it is necessary to continually update our knowledge to ensure proper recognition of allergens and appropriate treatment of patients. OBJECTIVE: This study aimed to profile photoallergic reactions in Canada. METHODS: A retrospective chart review of all patients who underwent photopatch testing at Toronto Western Hospital between January 2001 and December 2010 was completed. Photoallergic, allergic, and irritant reactions were recorded for 26 common allergens. RESULTS: Ninety-nine patients (61.9%) had at least 1 positive reaction to the test allergens. Fifty-four patients (33.8%) had at least 1 photoallergic reaction. All 26 allergens produced at least 1 allergic or photoallergic reaction. The most common relevant photoallergens were benzophenone-3, octyl dimethyl para-aminobenzoic acid (PABA) in 5% alcohol, and butylmethoxy-dibenzoylmethane. CONCLUSIONS: This study is the first to profile photoallergic contact reactions in Canada. It is clear that the culprit photoallergen in PACD can often be identified in a properly selected population. Future surveillance is necessary to continue to characterize PACD trends in Canada and to help better treat and screen this patient population.