I've seen some info online, but can you suggest an authoritative/exhaustive source on what health information, if any, one might gleam from the condition of one's fingernails, i.e., ridges, indents, coloration, spotting, etc.?
You've got the right idea with your question. Nails aren’t only coverings for the tips of your hands and feet, but they may also be indicators of underlying health issues. Although it's completely normal for nails to look different from one finger or toe to the next, and from one person to the next, abnormalities in the nail(s) may be a sign of more serious medical conditions or illnesses.
Some nail conditions and their associated illnesses include:
- Yellow nail syndrome: A slightly yellow or green tinge in your nails may be associated with some sort of respiratory condition. Yellow nail syndrome can also cause the nail(s) to be lacking in cuticles and even become detached from the nail bed. Two common causes of this nail condition are chronic bronchitis or lymphedema, the swelling of your hands.
- Pitting: Pits, or small depressions or dents in the nails, may be associated with the skin condition, psoriasis. Pitting may also be a symptom of reactive arthritis and alopecia areata.
- Clubbing: This occurs when nail tips curve around the fingertips, rather than growing straight past the fingers. This usually happens when fingertips become enlarged due to low oxygen levels in the blood. Clubbing may also be an indicator of lung disease, as well as inflammatory bowel disease and liver disease.
- Spoon nails: Spoon nails get their name because they look like the back of a spoon has been pressed on top of them, forming a dip in the nail. This dip is usually large enough to hold a drop of liquid and can be indicative of iron-deficiency anemia or hemochromatosis, which is a condition where the body absorbs too much iron. Heart disease and hypothyroidism may also be associated with this nail condition.
- Terry's lines: Also referred to as Terry's nails, this occurs when most of the nail is opaque, but the tip has a pink band. This may happen simply due to aging, but can also mean a more serious condition, such as kidney disease, congestive heart failure, diabetes, and liver disease.
- Beau's lines: Lines that run horizontally across your nails are the characteristic symptom of Beau's lines, and may appear when cuticle growth is disturbed by an injury or illness. Diabetes, peripheral vascular disease, scarlet fever, measles, mumps, pneumonia, and zinc deficiency are commonly associated with these lines.
- Onycholysis: This refers to the separation of nails from nail bed, which also makes the affected area turn white. Many circumstances can cause onycholysis, with the most common cause being physical trauma that causes the nail bed to separate from the nail. Onycholysis might also be seen in people who have thyroid disease, psoriasis, or have a reaction to certain products such as nail hardener or adhesives.
Although these descriptions mainly refer to fingernails, toenails can also take on similar appearances. Changes in both fingernails and toenails can indicate more serious conditions, if you have concerns about your nails, it's best to consult with your health care provider in order to get an actual diagnosis. If necessary, they can better understand what may be causing the nail abnormality and treat both the nail and any underlying health conditions to get you back on your (hands and) feet (literally!).Alice!