NEW YORK (CBS 2) — Many people worry about changes in their skin.  Slight differences on the outside may signal clues to what’s going on inside the body, but not every little discoloration and bump is something to worry about.

Three years ago, Lauren Finney thought she was having an allergic reaction, but the rash on the 26-year-old former model’s face was far more serious.  She was eventually diagnosed with lupus, an auto immune disease that can affect the skin, joints and other internal organs.

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“It hurt, it felt like it was needles, it was stinging, it affected my eyelids,” Finney told CBS 2’s Dr. Holly Phillips.

Dermatologist Dr. Doris Day says many serious health problems can manifest first in the skin.

“The skin is our largest organ and an amazing reflection of what goes on inside our body,” Day said, “things like diabetes, auto immune conditions,  hormonal conditions…even cancer can show up in the skin as an early sign and a first clue.”

There are clues to hidden health issues all over a person’s body.  Stress will often show up in lines on the nails and thinning hair, Phillips reports.  Even more serious conditions can be uncovered by looking more closely at the skin.

For example, flaky patches can mean psoriasis and signal a higher risk for diabetes and heart disease.

“It typically affects the elbows and knees and is often only a skin condition,” Day said, “but it can affect other organ systems as well.”

Skin discolorations or rashes might mean high blood pressure.  Fungal infections could be signs of Type 2 diabetes.  Cystic acne may point to polycystic ovary disease while itchy skin could indicate possible lymphoma.

“If your skin is drier and consistently and intractably itchy where you cant control that itch after a shower that might be a clue you need to see your internist,” Day told Phillips.

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Brownish bumps called seborrhea kerotosis could be a sign of liver or lung cancer.  A type of spider vein called “spider angiomas” can point to liver disease, Phillips reports.

“When they come out in crops all of a sudden a whole bunch of them at once,” Day says “that can be a clue to underlying liver disease or liver cancer.”

A nodule in the belly button could indicate ovarian or lung cancer and a tell-tale sign of lupus is the butterfly rash.  Lauren Finney didn’t have one so her case was more difficult to diagnose.

“It’s a rash in the face and the cheeks and the nose that comes out with even a little sun exposure,” Day said.

Finney talked about her ordeal and the uncertainly of knowing whether or not skin issues could be a sign of something more serious saying that while she noticed patches and irritations it was never the “classic tell tale sign that everyone says ‘oh that’s lupus’”

But after getting properly diagnosed, Finney’s lupus is being controlled and she’s offering some advice to others in her position.

“If something doesn’t feel right, it probably isn’t…you know your body better than anyone else,” Finney said.

Phillips says that there are two important clues to knowing if your skin condition is serious.  They include seeing a condition that you’ve never had before and if the condition doesn’t go away on its own within two to three weeks.  In either case, Phillips says, you should consult a physician.

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