Visão geral da fotossensibilidade cutânea: Fotobiologia, avaliação do paciente e fotoproteção

Abstract

Introduction: Cutaneous photosensitivity is an abnormal response to ultraviolet (UV) radiation and, in some individuals, visible light on the skin. One of the main characteristics of a photosensitive rash is its distribution. In most cases, it occurs on sun-exposed areas of the skin; the face, ears, dorsal forearms, the "V" area of ​​the neck, and the upper chest are commonly affected sites. However, it can occasionally occur on covered areas of the body, especially in individuals who use tanning beds. Careful clinical evaluation requires a detailed history, including age at onset, timing after sun exposure, duration of response, family history, and type of skin lesions that occur. Photodiagnostic and laboratory tests may be necessary. Treatment measures include photoprotection and, often, immunosuppressive medications. Objectives: discuss skin photosensitivity, patient assessment and photoprotection. Methodology: Integrative literature review based on scientific databases from Scielo, PubMed and VHL, from January to April 2024, with the descriptors “Photosensitivity”, “Assessment” AND “Photoprotection”. Articles from 2019-2024 (total 17) were included, excluding other criteria and choosing 5 full articles. Results and Discussion: Diagnosis of a photosensitivity disorder is based primarily on taking a history and performing a skin examination. The age of onset, timeline of the rash, family history, medication history, and appearance of the lesions are invaluable in narrowing down the differential diagnosis.  Laboratory evaluation may include ANA, anti-dsDNA, anti-Ro (SSA), and anti-La (SSB) titers and porphyrin studies based on a clinical suspicion of lupus erythematosus or porphyria. Skin biopsy can be useful when correlated with clinical findings. Phototesting to determine the minimum erythema dose (MED) and spectrum of action can narrow the differential diagnosis. Photopatch testing is useful in patients in whom a topical photoallergen is suspected. Photo protection through sun avoidance and sun protective clothing is essential. Broad-spectrum ultraviolet A and ultraviolet B sunscreens are helpful but may not adequately protect patients when used alone. Broad spectrum sun protections (UVA and UVB) with a minimum sun protection factor (SPF) of 30 provide protection for patients with photosensitivity in the UV spectrum. Products containing photostabilized avobenzone or ecamsule offer enhanced protection against UVA. Sunscreens that contain non-micronized zinc oxide and titanium dioxide also provide broad-spectrum photo protection. Conclusion: Sun avoidance and photoprotective clothing provide primary protection for patients with sensitivity to visible light. When skin exposure to sunlight is unavoidable, physical blocking sunscreens (titanium dioxide or zinc oxide) in an opaque, non-micronized formulation and tinted sunscreens can provide protection against visible light.