Patient perception, usage pattern and muco-cutaneous adverse effects of sunscreens using sunscreen patch test: A cross-sectional study

Background Exposure to solar radiation can have both beneficial and harmful effects on the skin. Sunscreens may prevent photoaging and photodermatoses, but most patients do not follow recommended application guidelines. With the rise in sunscreen use, cutaneous reactions to sunscreen ingredients (especially UV filters) are being reported frequently. However, Indian data on sunscreen usage and sensitisation are limited, underscoring the need for better understanding of usage patterns and sensitisation profiles. Aim We aimed to evaluate patient perspectives on sun protection and sunscreen usage patterns. We also documented associated adverse effects and performed patch testing using a dedicated sunscreen allergen series when indicated. Methods This cross-sectional descriptive study examined perceptions, usage patterns and adverse effects of topical sunscreens among 227 adults attending a tertiary care hospital in south India from May 2023 to April 2025. Structured questionnaires were used to assess perceptions and usage behaviours. Sunscreen application quantity was measured using a digital scale, and application density (mg/cm 2 ) was calculated. Patients reporting adverse reactions underwent patch testing with the Chemotechnique Sunscreen Series (21 haptens), with readings at 48 and 72 hours according to International Contact Dermatitis Research Group (ICDRG) criteria. Results Most participants were female (83.3%) and aged 18−30 years (73.6%). Almost all participants (96.9%) recognised the importance of sun protection. Less than half (48.5%) applied sunscreen at the recommended density of 3 2 mg/cm 2 . Many participants (58.6%) did not use sunscreen indoors, and only 21.6% reported reapplying it. Adverse effects (erythema, itching, and burning) were reported by 13.2% (30/227), predominantly among users of over-the-counter (OTC) sunscreens. These OTC sunscreens are non-prescription sunscreen products that can be purchased directly by consumers without a doctor’s prescription. Of the 30 symptomatic individuals, 17 underwent patch testing. Positive reactions to sunscreen filters were observed in three individuals (17.6%), with two reacting to more than one filter. Positive reactions were noted to PABA (para-aminobenzoic acid) and octocrylene in one participant, to benzophenone-3 in another, and to both bis-ethylhexylphenol methoxyphenyl triazine and diethylamino hydroxybenzoyl hexyl benzoate in the third. Limitations Sunscreen usage patterns and side effects were self-reported, introducing potential recall bias. Only 17 of the 30 symptomatic patients underwent patch testing, and photopatch testing was not performed, which may have led to underestimation of the true incidence of both contact and photoallergic reactions to sunscreens. Conclusion This study highlights significant gaps in awareness and proper sunscreen use among individuals in south India. Although most participants recognised the importance of photoprotection, many applied insufficient amounts and did not reapply as recommended. Adverse effects were reported by 30/227 of participants (13.2%), mostly among those using OTC sunscreens. Among the 17 who underwent patch testing, 17.6% (3/17) showed positive reactions. Promoting education on correct application techniques and raising awareness of potential side effects are essential to improve photoprotection practices.