White spots on nails are usually caused by minor injury to the nail and are harmless. They are not usually a sign of calcium deficiency.
Cause
White spots (leukonychia punctata) are usually caused by minor injury to the nail matrix, such as bumping or manicure damage. They grow out in 6 to 9 months, as fingernails grow about 3 mm a month.
Myth
They are not caused by calcium deficiency.
Other causes
- Fungal infection (white superficial).
- Allergic reaction to nail products.
- Zinc deficiency (rare).
- Medical conditions, such as kidney disease, in rare cases (when lines run across all nails).
What to do
Protect nails, avoid harsh products and moisturize.
See a doctor if
Spots spread, change color or appear on many nails, or the nail changes shape.
Timeline
Gone once the nail grows out.
What causes white spots
White marks on nails are called leukonychia. Small spots, called punctate leukonychia, are most common. They are usually caused by minor injury to the nail matrix, the tissue at the base of the nail where the nail grows. Banging the nail, aggressive manicures, nail biting or pressing too hard on the cuticle can cause it. Since the nail grows slowly, spots appear well after the injury.
The calcium myth
White spots are not a sign of calcium deficiency. This is a long-standing myth. Nails are made of keratin, and calcium levels in the blood are tightly controlled. In people with normal diets, white spots rarely relate to nutrition.
Timeline
Fingernails grow about 3 millimeters a month, and take about 6 months to grow out completely. Toenails grow about 1 millimeter a month and take 12 to 18 months. A spot moves up the nail as it grows, so a spot that appeared after an injury will disappear as the nail grows out.
Other causes
- Fungal infection, which causes white, crumbly patches on the surface, often on toenails.
- Allergic reaction to nail polish, hardeners or acrylic products.
- Zinc deficiency or other nutrient problems, which are rare causes.
- Medications, including chemotherapy.
- Illness such as kidney disease, liver disease or heart failure, which can cause broad white nails.
- Poisoning by arsenic or other heavy metals, which cause transverse white lines called Mees’ lines.
- Psoriasis and eczema.
What to do
- Do nothing for small spots. They grow out.
- Avoid picking at the nail or cuticle and limit harsh manicures.
- Wear gloves for cleaning and dishwashing.
- Keep nails moisturized with a cream or cuticle oil.
- Take a break from gel and acrylic.
- Treat fungus with antifungal medication if confirmed.
See a doctor if
Many nails are affected, whole nails turn white, nails change shape, thicken, split, or crumble, you notice dark lines, there are other symptoms such as fatigue or swelling, or if spots keep returning without injury. A doctor can scrape a sample to test for fungus.
Nail growth facts
Fingernails grow about 3 mm per month, so a white spot (leukonychia) moves from the base to the tip in roughly 6 months. Toenails grow about 1 mm per month. Most spots are caused by minor trauma to the nail matrix from bumping, nail biting or aggressive manicures. Punctate leukonychia is the common type with small dots. Transverse white lines across the nail can point to illness, chemotherapy or heavy metal exposure, and fully white nails can occur in liver disease. Fungal infection causes white, chalky patches on the nail surface that can be scraped. Zinc deficiency is rare, and supplements are not advised without testing. Protect nails and avoid acrylic removal damage.
Based on data from the American Academy of Dermatology
