Prevalence and causative allergens of contact cheilitis in Thailand.

BACKGROUND: Cheilitis is an inflammatory condition of the lips. Its causes can be exogenous (irritants, allergens), endogenous (atopic dermatitis, systemic disorders) or unknown. OBJECTIVES: To determine the prevalence of allergic contact cheilitis (ACC), its risk factors, and common allergens in patients with cheilitis at a Thai university-based tertiary care hospital. METHODS: A retrospective chart review was conducted on patients with cheilitis referred for patch testing between January 2007 and December 2021. RESULTS: Among 5366 patients referred for patch testing, 410 (7.6%) had cheilitis. ACC was diagnosed in 32% of the cheilitis patients. Compared to non-ACC cases, the patients with ACC were more likely to be young and female and have a disease duration of <3 months, no underlying disease and a white-collar job (p-value <0.05). The most common contact allergens were patient's products (73.3%), nickel sulfate (29.8%), potassium dichromate (14.5%), castor oil (14.3%) and benzalkonium chloride (13.0%). Lip cosmetics and toothpastes were major ACC sources. CONCLUSIONS: ACC should be considered in cheilitis patients, especially in patients with specific risk factors. Castor oil is an emerging allergen. Patch testing using commercial allergen series and patients' own products is crucial for identifying causative agents. The development of a specific cheilitis series is warranted.

Trends in formaldehyde and formaldehyde-releaser contact allergies as compared with market exposure in Thailand.

BACKGROUND: Formaldehyde and formaldehyde releasers (FRs) are common preservatives in cosmetics and household products. Their contact allergy trends are decreasing in Europe and America, but trend data for Asia are limited. OBJECTIVES: The first objective was to determine the prevalences of and trends in contact allergies to formaldehyde and FRs. The second objective was to establish how often formaldehyde and FRs were mentioned on the labels of products sold in the Thai market. METHODS: Twenty years of data on patch test results for formaldehyde and FRs were reviewed. Their frequency of mention on the labels of 5855 products was analysed. RESULTS: The trends in contact allergy to formaldehyde and FRs were decreasing. The overall prevalence of formaldehyde contact allergy was 2.5%. The most common FR to cause contact allergy was quaternium-15. Formaldehyde and FRs were identified as ingredients in 10.2% of the products surveyed. Dimethylol dimethyl hydantoin was the most common FR (5.2%). The highest use of formaldehyde and FRs (15.5%) was in hair care products. CONCLUSION: Although contact allergy trends in Thailand were decreasing, the proportion of products with FRs remained high. Comprehensive and universal legislation is needed to control the presence of formaldehyde and FRs.

Characteristics and common ultraviolet filter usage of sunscreens purchased online: Cross-cultural analysis across 5 continents.

BACKGROUND: A wide range of sunscreen products are available globally. Designed to meet various customer needs, they differ in formulations type, textures, ingredients, ultraviolet (UV) protection capabilities, and other properties. Knowing the factors influencing the purchase of sunscreens and the UV filters commonly used in each global region would be beneficial for dermatologists, consumers, and regulators. METHODS: Data on 50 best-selling sunscreens from each of 20 countries on 5 continents (1000 products in all) were retrieved from Amazon Marketplace during the period from January to July 2021. RESULTS: Among the 5 continents, Asia had the highest proportion of consumers (71.1%) choosing high sun protection factor (SPF) sunscreens (SPF ≥50). In contrast, Europe had the highest percentage (11.8%) purchasing <30 SPF sunscreens. The lack of standard UVA protection labeling was significantly highest in South America. The use of inorganic-based sunscreen was highest in North America, and across all continents, those products were significantly more expensive than organic-based sunscreens. Globally, lotions were the most favored formulation type. "Nongreasy/dry touch" (45.1%) and "lightweight texture" (40.4%) were the most common promotional terms used. The most common UV filters differed among regions. Iron oxide, which can function as a visible light filter, was most frequently found in sunscreens in South America (20%) and North America (19.3%). CONCLUSIONS: The regional factors influencing the purchase of sunscreen products differed. A considerable number of sunscreens may not provide adequate sun protection for consumers. Dermatologists should recommend sunscreens with sufficient UV protection that suit the skin of individual consumers.

The Value of Patch Testing With Shoe Material Samples in Patients Suspected of Shoe Allergic Contact Dermatitis.

BACKGROUND: Patch testing is the standard diagnostic tool for shoe allergic contact dermatitis (ACD). As shoe materials change over time, utilizing commercial allergen series might be ineffective. However, because testing with patients' shoe samples is laborious, its value is questioned. OBJECTIVE: The aim of this study was to ascertain the benefits of patch testing with patients' shoes by comparing the frequencies of patch-test positivity of shoes and shoe-related allergens in baseline series for suspected shoe ACD patients. METHODS: A retrospective study was conducted of patients with clinically suspected shoe ACD who underwent patch testing with baseline series and shoe samples 2000 to 2019. RESULTS: Almost half of the cohort (77 of 178; 43.3%) was diagnosed with shoe ACD. Of those 77, 48 (62.3%) were positive to shoe-related allergens from the baseline series, whereas 53 (68.8%) were positive to their shoe materials. The prevalence of tests positive to shoe material but negative to shoe-related allergens was 29 of 77 (37.7%). The most common shoe-related allergens were potassium dichromate (7.9%), carba mix (6.8%), and mercapto mix (6.7%). CONCLUSIONS: Patch testing with shoe materials increased the diagnostic yield by 37.7 percent. To diagnose shoe ACD, testing of shoe materials may compensate for unknown, scarce, or novel allergens not in the baseline series.

Ultraviolet filters in sunscreens and cosmetic products-A market survey.

BACKGROUND: As several reports have raised a variety of environmental, health, and safety issues related to ultraviolet (UV) filters, it is crucial to understand the trends in the exposure of the population to UV filters. OBJECTIVE: To determine the frequency of UV filter usage in sunscreens and other cosmetic products in Thai market. METHODS: We surveyed the UV filter labelling on sunscreens and cosmetic products sold in the Thai market. In all, 312 sunscreens and 1350 other cosmetic products were investigated. RESULTS: Titanium dioxide was the most frequently used UV filter in both sunscreens (66.7%) and other cosmetic products (68.4%). Ethylhexyl methoxycinnamate was the most common organic UVB filter, whereas butyl methoxydibenzoylmethane was the most common organic UVA filter. In sunscreens aimed at children, bis-ethylhexyloxyphenol methoxyphenyl triazine was the most commonly used UV filter. The most frequent co-occurrence of UV filters was titanium dioxide and ethylhexyl methoxycinnamate. CONCLUSIONS: Titanium dioxide was the most commonly used UV filter, which differs from the findings of previous surveys. Knowing the availability and frequency of each UV filter provides valuable information about consumer exposure levels, facilitates refinements of the allergen series in patch testing, and enhances the monitoring of adverse effects of UV filters.

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.

Methylchloroisothiazolinone and/or methylisothiazolinone in cosmetic products-A market survey.

BACKGROUND: There was a global epidemic of methylchloroisothiazolinone (MCI) and/or methylisothiazolinone (MI) contact allergy from 2009 to 2015. In response, the Thai Ministry of Public Health regulated the use of MCI/MI in cosmetics. OBJECTIVE: To survey the presence of MCI/MI and MI alone, as labelled on cosmetics sold on the Thai market, before and after the ministerial directive. METHODS: The presence of MCI and/or MI in leave-on and rinse-off cosmetics sold on the market, based on the labelling of ingredients in 3445 products, was analysed. RESULTS: Before the implementation date, most leave-on products contained MCI/MI. After the regulations came into force, the only leave-on cosmetic subcategories that complied with the law were facial skin-care, sunscreen and make-up products. MCI/MI and MI alone were found on the labels of both leave-on and rinse-off products, the presence of each varying between product subcategories. CONCLUSIONS: Despite the ministerial regulations restricting their use, MCI and/or MI are still found in cosmetics sold on the Thai market. Dermatologists should be aware of this situation, and counsel patients to avoid products containing MCI and/or MI.