Here’s What Your Nail Shape and Texture Say About Your Health

In a previous article, we saw how the color of our fingernails is one of the easiest changes to spot—and dismiss. But shape and texture are where your nails may offer other clues. A ridge that shows up out of nowhere, a spoon-like dip at the center, nails that suddenly curve—these aren’t always cosmetic quirks that you can file away and be done with. 

They can be our body’s way of telling us that something’s wrong, pointing to something beyond our fingertips that we might not even realize is happening.

We went back to the three board-certified dermatologists—Mae Ramirez-Quizon, MD, FPDS, Criselda L. David-Javier, RN, MD, DPDS, DPADSFI, and Anna Palabyab-Rufino, MD, FPDS,—to explain what these different nail shapes and textures can mean for our health and what we should bring up in our next derm appointments.

What ridges are actually telling you

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Vertical ridges

These are among the least concerning changes your nails can show. Dr. Criselda David-Javier calls them “wrinkles of the nail”—they’re often as normal as aging. Dr. Mae Ramirez-Quizon agrees, saying, “Fine, evenly spaced ridges are usually harmless and tend to become more noticeable with age as nail growth and cell turnover slow.” Dr. Palabyab-Rufino adds that the dryness from eczema can also make th em more noticeable. 

These ridges are worth taking a second look at if they’re new, worsening, or isolated to a single nail—especially if they’re paired with pain, discoloration, or swelling. “These findings may indicate an inflammatory nail disorder or, less commonly, a nail-unit tumor,” said Dr. Ramirez-Quizon. 

Horizontal ridges (Beau’s lines)

Horizontal ridges are different. Known as Beau’s lines, these can appear when nail production temporarily stops. All three dermatologists point to similar causes or triggers: high fever, severe infection, chemotherapy, major surgery, or significant physical stress. Dr. Anna Palabyab-Rufino adds diabetes and thyroid conditions to that list, while Dr. David-Javier notes acute zinc deficiency and uncontrolled diabetes, too. 

And another useful tip: nails grow at a fairly predictable rate—roughly 3mm a month, according to Dr. David-Javier. This means dermatologists can sometimes estimate when the disruption happened by looking at the position of the ridge. 

Clubbing and spoon-shaped nails: what they mean

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Clubbing

Clubbing isn’t quite subtle once you already know what to look for: the fingertips become rounded and enlarged, with nails curving over them. Dr. Ramirez-Quizon says that this isn’t cosmetic at all: “Clubbing can be associated with underlying lung, heart, gastrointestinal, or liver disease, although it can occasionally be hereditary or occur without an identifiable illness. It should not be assumed to be caused solely by low blood-oxygen levels,” she said. 

Dr. David-Javier also placed a number on it, citing the study on the British Journal of Dermatology she previously mentioned in a previous article: “It has 92% specificity for pulmonary and cardiovascular conditions like bronchiectasis, lung cancer, or congenital heart defects. It can also occur with some gastrointestinal disorders, blood disorders, and in heavy smokers.” 

Spoon-shaped nails

Spoon-shaped nails or koilonychia are characterized by thin, concave nails that look scooped up in the center. All three dermatologists say that this is commonly associated with iron-deficiency anemia. 

“Without enough iron, the body cannot produce enough keratin, weakening and thinning out the nail plate, causing it to collapse inward,” Dr. Palabyab-Rufino explains. 

Dr. David-Javier adds an important warning from her own practice: “In my clinic, I always order a CBC and ferritin level when I see true koilonychia, but by the time you see spooning, your iron stores are often significantly depleted.”

However, Dr. Ramirez-Quizon noted one exception found in newborns and young children. “Spoon-shaped nails can be a normal developmental finding because their nail plates are still thin and soft. They often flatten and strengthen naturally as the child grows.” She also added that persistent spooning or spoon-shaped nails should still be discussed with a pediatrician or dermatologist.

What thyroid disease, anemia, diabetes, and psoriasis look like on your nails

Beyond nail shape, some health conditions can also be associated with recognizable nail changes. Here’s what thyroid disease, anemia, diabetes, and psoriasis can look like on your nails.

Thyroid disease

An underactive thyroid can make the nails look dry, brittle, ridged, and slow-growing. An overactive one can cause different changes—faster growth, nails lifting from the nail bed, and other changes. Dr. David-Javier says, “Onycholysis, especially on the ring and middle fingers, is strongly associated with thyroid dysfunction, particularly hyperthyroidism.” Dr. Palabyab-Rufino adds that vertical and horizontal ridging, splitting, and general softening or thinning are changes to also watch out for. 

Anemia

Iron-deficiency anemia can make the nail beds look pale, but color isn’t reliable enough to make a diagnosis. Dr. Ramirez-Quizon says, “More severe or long-standing iron deficiency can cause koilonychia, or spoon-shaped nails, in which the nail plates become thin and concave with raised edges.” When paired with fatigue, dizziness, or shortness of breath, these changes may warrant a proper checkup. 

Diabetes

While diabetes doesn’t necessarily have a specific nail look, Dr. Ramirez-Quizon says that people with diabetes are more prone to fungal nail infections. “These can make the nails yellow or white, thick, brittle, cracked, distorted, or separated from the nail bed,” she explained. “Poor circulation and nerve damage can also make cuts, ingrown nails, and infections around the toenails harder to notice and slower to heal,” she later added. 

Dr. Palabyab-Rufino also notes horizontal ridging and nail thickening as other changes that may occur. 

Psoriasis

This one can have a distinct look: tiny pinpoint dents called pitting, plus onycholysis and sometimes a yellow-red-brown discoloration under the nail called the “oil-drop sign.” Dr. David-Javier flags this as one that needs attention: “Clinical studies show that 80 to 90 percent of people with psoriatic arthritis have nail changes, so don’t ignore these signs if you have psoriasis or joint pain.” 

Across these four conditions, one thing is clear: no single nail change can confirm a diagnosis on its own. But when paired with other symptoms, such as fatigue or unexplained weight changes, it may warrant further examination. 

Are brittle or ridged nails a sign of deficiency?

Brittleness, peeling, or ridged nails might be thought of as signs of vitamin deficiencies—but all three dermatologists say that it’s not necessarily the case. Dr. Ramirez-Quizon is direct: “Although nutritional deficiencies can affect the nails, everyday exposure and local nail damage are much more common causes.”

So, what’s actually going on? 

Dr. David-Javier notes a few everyday culprits she sees more often than an actual deficiency in her clinic:

• Frequent wet-dry cycles;
• Acetone and gel polish removal;
• Hypothyroidism, which causes thick, brittle nails with vertical ridges; and
• Aging, which naturally reduces nail moisture

Dr. Ramirez-Quizon also adds dry weather, household chores, and exposure to chemicals and solvents to the list. In short, your nails are often reacting to your daily routines rather than your diet.

When nutrition is actually the cause

That said, deficiencies aren’t off the table. Dr. Palabyab-Rufino outlined a few patterns that people should know: “Iron deficiency can show spooning or weakness, while vitamin B deficiency shows brittle nails, some ridging, and bluish discoloration or dark streaks. Vitamin D deficiency can show brittle nails and pitting, while zinc deficiency can cause white spots as well,” she explained. 

Worth flagging, though: as we covered in our previous piece, white spots are specifically still more commonly caused by minor trauma to the nail matrix, such as biting, bumping, or an aggressive manicure. Zinc deficiency is a possible contributor in more severe cases, but not the default explanation for it.

Dr. Ramirez-Quizon said that nail changes only happen when nutritional deficiencies are significant. Thus, echoing the idea said earlier, “Appearance of the nails alone cannot identify which nutrient is lacking.” 

When should you consider a possible deficiency?

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Dr. David-Javier says, “If you have brittle nails plus other symptoms like fatigue, hair loss, or cold intolerance, it’s worth checking thyroid function and iron studies.” Otherwise, she says the fix may be quite simple: “Like wearing gloves for wet work, moisturizing not just your hands but also your cuticles, and taking breaks from gel manicures.” 

Dr. Palabyab-Rufino offers another place to start: “If you notice recent changes on your nails, you can start re-evaluating your habits to check if anything you’re doing or not doing is contributing to these.” 

Ultimately, changes in your nails’ shape and texture aren’t necessarily cause for alarm; what matters is recognizing new or unusual patterns. A ridge here, a bit of brittleness there—on their own, they may not mean much. But when paired with what your body is feeling, whether it’s fatigue, joint pain, or a fever that won’t break, they could be your body’s way of telling you that something wrong. 

The real skill isn’t memorizing all these signs and conditions and treating every change as a red flag—it’s simply paying attention to changes happening in your body. If something looks new or unusual, bring it up with your board-certified dermatologist, who can determine whether it warrants a closer look.

Of course, not every nail issue comes from what’s happening inside your body. Sometimes, it’s what happens during our monthly nail tech visits. One popular procedure has some dermatologists concerned—and it’s one we beauty girlies absolutely love doing.