What is wrong with Senator Mitch McConnell’s hands and lips? The question that has flooded all over social media after photos of the Senate Majority Leader’s hands appeared black and blue with a bandage around his thumb.

Now people really want to know what is wrong with McConnell’s mysteriously discolored hands. They wonder whether his health is deteriorating after surviving polio and undergoing heart bypass surgery.

McConnell has not yet publicly disclosed any health issue. On Thursday, he told reporters that there were “no concerns,” according to CNN. Reporters asked him about any health issue people should know about, he replied, “of course not.”

The 78-year-old did not respond to questions about getting treated by a doctor. Nevertheless, people on social media started investigating.

According to the Cleveland Clinic, having any kind of injury, like a cut or other accident, can cause bruising. “Bruises form when blood pools under the skin after an injury,” the clinic explained. “They typically start out as black and blue, brownish or purple, and may change color as they fade. Older people are more prone to bruising.”

Dermatologist Dr. Gary Goldenberg of Icahn School of Medicine at Mount Sinai Hospital told Health, “The most common reason for bruising is injury. This can be in many forms in different patients.”

Bruises can also be a result of an IV or blood draw, according to Dr. Goldenberg says. “In older patients, the most innocuous trauma can cause bruising,” he explained. “This is due to the skin thinning with age.”

Poor blood flow to the extremities could be another reason. Dr. Lewis Nelson of Rutgers New Jersey Medical School and University Hospital told Health there could be “multiple reasons why someone might have poor blood flow, ranging from being exposed to the cold to having lung or vascular disease, but that can lead to easy bruising.”

“Among other things, blood cells help to carry oxygen to various parts of the body, but if those blood cells don’t have as much oxygen as they should, they can cause cyanosis, or a bluish tint, to the skin,” Dr. Nelson explained.

Other potential causes of bruised extremities include cancer treatments (chemotherapy), liver cirrhosis, sepsis, broken blood vessels, endocarditis, or Raynaud’s phenomenon. Also called Raynaud syndrome, Raynaud’s phenomenon is a rare blood disorder that usually affects the fingers and toes, according to Medline Plus. Tiny arteries that supply blood to the skin, especially the skin of the extremities, constrict excessively in response to cold, causing discoloration.