When you visit your doctor about a problem, your doctor needs to make sure that problem does not represent some sort of life threatening issue like cancer. When a physician evaluates a patient on the internet, there are not as many clues to go on to make that judgement so patients and physicians need to know when it is ok to make an educated guess and when you have to be sure of the diagnosis. A growth or a mole can always represent a skin cancer however a localized rash is rarely indicative of a serious medical condition.

The photo below was submitted by a young woman who thought she had ringworm. The doctor thought it looked more like nummular dermatitis but couldn’t be sure just from the photos. He reasoned that a trial of therapy with a topical steroid would not pose a risk of serious harm to the patient. If things didn’t clear, bringing the patient to the office for a KOH test could then be done. The rash cleared with triamcinolone 0.1% ointment.

Used with permission


Squamous cell carcinoma (SCC) is usually a mild form of skin cancer that can be very dangerous in certain situations.

This patient noticed a sudden growth of this crusted red nodule on a frequently sun exposed area of his arm that resembled an SCC. Of note, the patient had a kidney transplant several years before. To prevent rejection of his transplanted kidney, the patient takes several medications that suppress his immune system. These immunosuppressive medications can make skin cancers more frequent and aggressive. As a result, anyone using these medications, even for other conditions, has a higher chance of dying from skin cancer. Patients on these medications have to be careful with the sun and should be followed closely by a dermatologist.

Squamous cell carcinoma