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Ultraviolet (UV) radiation causes both acute and chronic skin changes. Sunburn is a partial-thickness burn, which may become a full-thickness injury if infected. “Sun poisoning” is a severe systemic reaction to UV radiation. Patients may complain of nausea, vomiting, headache, fever, chills, and prostration. Excessive UV radiation may cause injury to the cornea and conjunctiva, termed UV keratitis (photokeratitis, snow blindness). This painful condition may occur in skiers, welders, or tanning salon patrons who do not wear proper eye protection.
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There are several types of photosensitivity reactions (photodermatoses). Phototoxic reactions are abnormal responses to UV radiation caused by substances that are ingested (eg, prescription or over-the-counter medications) or applied to the skin. There is a direct relation between the amount of UV exposure and severity. Photoallergic reactions are clinically similar to contact dermatitis and, like phototoxic reactions, may be precipitated by ingested or applied drugs. Unlike phototoxic reactions, photoallergies may be precipitated by a small amount of light. Phytophotodermatitis is precipitated by skin contact with certain plants followed by exposure to UV radiation.
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