Sunburn is generally easy to recognize and diagnose. Red, tender skin that follows unprotected ultraviolet (UV) light exposure is most times a telltale sign. This may not be at the beach or pool — sunburn can occur at any time, even while driving in the car. UV rays can come right through the windows, even on a snowy day. If there is a concern regarding sunburn, it is advisable to see a health care provider. Sunburn concerns include: if the burn does not resolve after a week; if there is extensive blistering (more than 20 percent of the body’s surface area); associated high fever (102° F); nausea or vomiting; or red streaking or yellow discharge. The doctor will do a physical exam and order specific diagnostic tests if need be.
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The Physical Exam
During the physical exam, the doctor will likely first take vital signs, such as hydration, temperature/fever and pulse. They will then examine the skin to see how much body surface area is burned and whether or not there are blisters. The doctor may ask about the level of pain the patient is experiencing as well as ask questions regarding nausea, vomiting or headache. The dermatologist will recommend a skin cancer screening for anyone who has been sunburned. This is an exam that checks for lesions suspicious for skin cancer. It is conducted with the doctor’s eyes and a small magnifying tool called a dermatoscope. If a questionable lesion is identified, then a skin biopsy would be performed.
Some skin conditions can mimic sunburn. Rosacea is an inflammatory skin process whereby blood vessels in the face dilate, leading to flushing and a pinkish hue that is much like sunburn. The difference is that in the case of rosacea, patients may also have acne-like eruptions around the mouth, nose or eyes. There are generally no additional laboratory tests that go along with a suspected rosacea diagnosis.
Systemic lupus erythematosus (SLE) is an autoimmune disease that can manifest on the skin after sun exposure. This presents as a “butterfly” rash across the nose and cheeks and looks very similar sunburn. This is often accompanied by fever, malaise and joint aches. If the health care provider is questioning a diagnosis of SLE, they may order blood tests to check a complete blood count, kidney and liver function tests and an antinuclear antibody test, all of which assess for an autoimmune process. If there is any question between the two diagnoses, this panel of labs should help discern the difference.
If a patient is still getting sunburned despite the fact that they are using sun-protective precautions and avoiding UV light as much as possible, their dermatologist may recommend phototesting. These are specialized tests that confirm or negate the presence of an abnormal sunburn reaction (i.e., people who are extremely sensitive to the sun). These tests are used to evaluate skin eruptions like a rash, blistering, itchiness or hives that get noticeably worse with even minimal UV exposure. Phototests are performed by seeing if an eruption occurs by exposing small areas of the skin to varying doses of artificial UVA and UVB rays. A positive reaction at a low dose of UV exposure confirms that a person is indeed more sensitive than others to sunlight. This may be followed up by an assessment of past medications (which may cause sun sensitivity) or a skin biopsy to rule out other causes of inflamed skin on exposed areas.