Sunscreens
The use of photoprotective agents, whether sunscreens per se or in cosmetics, has increased greatly in recent years due to recognition of the carcinogenic and skin aging effects of UV radiation. The most frequent adverse reaction to the use of these substances is irritation, which occurs in more than 15% of users.64 The prevalence of sensitization among patients with suspected ACD is low, probably less than 1%.10 Benzophenones—and oxybenzone and dibenzoylmethanes (avobenzone) in particular—are the main sensitizing agents in sunscreens. p-Aminobenzoic acid and its derivatives are not widely used today, and so their prevalence as allergens is low. To date, there have been no reports of allergy caused by physical filters such as zinc oxide and titanium dioxide. 102 and 103 In addition to the substances used as sunscreens, other ingredients may be the cause of ACD. 104