skin expert has recently shed light on what the ridges on your nails could mean—and when it’s time to take action and see a doctor. Dr. Ross Perry, a skin specialist at Cosmedics, explains that these ridges can signal various health issues, ranging from nutritional deficiencies to dehydration, or even certain skin conditions.

According to Dr. Perry, deficiencies in key vitamins or minerals could cause ridges to appear. “Nutritional factors like a lack of Vitamin A, or if your body is low on protein or calcium, may lead to ridges forming,” he said. “In more extreme cases, a severe iron deficiency can cause noticeable changes to your nails, such as the development of ridges”

However, not all ridges are cause for concern. Dr. Perry emphasizes that most nail changes aren’t linked to anything serious. Common habits such as picking at your nails can also lead to these imperfections. The NHS adds that nail issues, like brittle or discolored nails, are often not indicative of a severe medical condition. “They clarify that most nail issues are typically not linked to serious health concerns.” “Common issues include nails that are brittle, loose, or change color or shape.”

But there is one exception that could point to a more serious underlying condition. Dr. Perry cautions that “severe, deep ridges,” though rare, might be indicative of a serious illness, like kidney disease, and should prompt a visit to the doctor. Additionally, conditions like diabetes can also trigger such changes in your nails, so it’s important to pay attention to these warning signs.