16 Disturbing Things Your Nails Reveal About Your Health

10. Concave Nails

Concave nails, also known as spoon nails or koilonychia, are usually caused by iron deficiency anemia. Sometimes, concave nails are a sign of a fungal infection, psoriasis, or lichen planus. They may also be hereditary, caused by an injury, or by environmental factors such as tight shoes or overexposure to petroleum products.

Thumb sucking in babies and toddlers can also be a cause. Other diseases that can cause concave nails include diabetes, heart disease, hypothyroidism, and lupus.