Our skin is a vital indicator of health. It indicates whether you are sufficiently hydrated or are eating a balanced diet. It may reveal underlying systemic diseases such as diabetes, autoimmune conditions or even cancer. Many diseases have characteristic skin signs associated with them. For example, lupus often presents with a malar rash on the face. This is a red rash on the cheeks that is sometimes described as a butterfly rash. Generalized itch on our skin is another symptom that often has an underlying systemic cause.



You can tell a lot by examining someone’s skin. In skin that is sun-damaged, we often see deep wrinkles and brown spots. As we get older, our skin thins and bruises easily. If someone has an impaired skin barrier, they can develop eczema. This often presents as red, scaly plaques on the skin.

Viruses often manifest on the skin. Children commonly get viral rashes after upper respiratory illnesses. Before there was a Varicella vaccine, chickenpox was very common. In adults, it can manifest as shingles aka herpes zoster. Molluscum contagiosum and warts caused by the HPV virus are extremely common in children as well. Warts (aka verruca vulgaris) are very common on the hands and the soles of the feet. Herpes virus (specifically HSV-1) is also very common and can present as cold sores on the lips. Pityriasis rosea is another common virus that is referred to as the “Christmas tree rash” because of the pattern it displays on the trunk.

We are protected against many viruses from vaccines but they often do not protect against all virus strains. For example, someone with the flu vaccine can still get the flu if they catch a different strain of the virus.

We are learning more and more about Coronavirus (COVID-19) rashes. A person may be asymptomatic but have a rash that is unexplainable. Current COVID-19 symptom checkers and standard diagnostic procedures may not recognize these conditions. We have seen this recently with the COVID virus which often presents as a patchy rash but can also present with hives. One interesting phenomenon is known as COVID toes.



A swelling or discoloration on the toes may be an indicator of an otherwise mild case of COVID. As more people recover from the virus, we are expanding our knowledge of all the skin signs.

Opu Labs is now developing an AI based skin analysis application which will assess the risk of COVID-19 and other viral infection and help track the extent of the disease. You can learn more about the initiative at www.opulabs.com/covid-19.



Dr. Anna Karp is a native New Yorker who grew up on Long Island’s South Shore. Dr. Karp attended medical school at Touro College of Osteopathic Medicine. After receiving her medical degree, she completed dual residencies in Family Medicine and Dermatology at St. John’s Episcopal Hospital in Far Rockaway, New York. Dr. Karp specializes in medical, cosmetic, and surgical dermatology and treats both adults and children. She is a fellow and member of the American Academy of Dermatology, American Osteopathic College of Dermatology, and the American Medical Association. Dr. Karp is also an advisor to Opu Labs.