You may trim them, file them, or even polish them, but your fingernails and toenails are more than decorative. Their appearance can reflect what\u2019s going on inside your body, and changes can offer insight into your general health \u2014 and perhaps even signal a cause for concern.\nDo Your Fingernails Reveal Health Troubles?\nIt\u2019s normal for nails to have some imperfections, but the variations below may indicate health problems.\nBeau\u2019s lines. These horizontal indentations across the nail beds can be caused by an injury, but they may also form in the presence of an illness, such as peripheral vascular disease, uncontrolled diabetes, high fever, or zinc deficiency.\nBlue nails. Very cold temperatures can temporarily slow the flow of blood through the skin leading to a bluish nail color; this typically goes away when you warm up. In Raynaud\u2019s disease, the fingers and toes blanch, then turn blue and may become numb or painful on exposure to cold. Blue fingernails can also be due to low levels of oxygen in the blood, which is a symptom of many different respiratory problems, including asthma, emphysema, chronic obstructive pulmonary disease, and chronic bronchitis.\nRELATED:\u00a0Living With Raynaud\u2019s Phenomenon\nBrown lines. If a line or discoloration stops at or before the cuticle, it\u2019s likely the result of a mole. However, brown spots or lines that run into the cuticle of your nail could be a sign of melanoma and warrant a visit to your physician.\nClubbed nails. This problem is the result of an increase in tissue growth around the fingertips, which gives nails a curved appearance. It usually occurs over the course of years and is painless \u2014 but not always harmless. Clubbed nails may stem from chronic low levels of oxygen in the blood and can signal lung disease. They may also be present in people with cystic fibrosis, cardiovascular disease, liver disease, inflammatory bowel disease, and AIDS.\nPitted nails. Tiny pits or depressions in the nails are common in people with psoriasis, as well as those who have the autoimmune disease alopecia areata (hair loss) or inflammatory arthritis.\nSpoon nails. Also known as koilonychia, these soft, scoop-shaped nails often develop with iron deficiency anemia, as well as the liver disease hemochromatosis, hypothyroidism, and heart disease.\nWeak, brittle nails. Splitting, peeling, and otherwise weak nails can be a sign of aging, but they may also be a symptom of hypothyroidism. Nails can also become brittle and weak if you overuse nail polish or regularly expose your hands to moist conditions, such as washing dishes or swimming.\nWhite spots on nails. Contrary to popular belief, white spots aren\u2019t caused by a calcium or zinc deficiency. Known as leukonychia, they are often simply signs of a past injury to the base of a nail, an allergic reaction to nail polish or other products or a mild infection.\nYellow nails. Thick, yellow nails occur when nail growth slows, often due to chronic bronchitis, emphysema, or another severe respiratory condition. Yellow nails can also result from onychomycosis or nail fungus; this common condition can also cause nails to turn brown and opaque and to separate from the nail bed.\nIf you\u2019re worried about the state of your nails, see your doctor to rule out any serious conditions. Visit the UPMC Department of Dermatology website for more information. You can even schedule an online appointment with UPMC eDermatology, powered by UPMC AnywhereCare.