While most nail changes are harmless, unusual long dark streaks, clubbed nails, or yellow discoloration can signal declining health.

Yellow nails

Nails can naturally yellow due to aging or smoking. However, yellow nails can also indicate a fungal infection. This condition often begins with white, yellow, or brownish-yellow discoloration before the nails thicken, become brittle, or crumble. Psoriasis can also alter nail color, causing them to pit and thicken.

Unusual yellow nails can indicate a medical condition. *AI-generated image*

Dry, cracked, or brittle nails

Frequent use of nail polish remover or low-quality dish soap without gloves can make nails dry, cracked, and brittle.

According to Healthline, if brittle nails persist without these obvious causes, conditions like psoriasis, hypothyroidism, or eczema might be considered. Hypothyroidism reduces thyroid hormones, which slows metabolism and decreases blood flow to the nail area, negatively impacting nail structure.

Horizontal ridges on nails

Lines running horizontally across the nails, or deep grooves, often appear when nail growth is temporarily interrupted. If the body is working hard to fight illnesses like fever, flu, or pneumonia, nail growth can temporarily halt, leading to these dark horizontal ridges.

Deformed nails

Swollen fingertips and abnormally convex or curved nails, resembling drumsticks (clubbing), can be linked to lung and chest conditions such as lung cancer, cystic fibrosis, or bronchiectasis. Conversely, certain skin diseases or iron deficiency anemia can cause nails to become deeply concave in the middle, creating a spoon-like shape (koilonychia).

Dark streaks

Dark streaks on nails are often caused by trauma, leading to blood pooling and bruising beneath the nail. However, according to Health, if a new dark brown or black streak appears unrelated to injury, tends to spread, gradually darkens, or is accompanied by a persistent, painful lump, it could signal subungual melanoma – a type of skin cancer.

Everyone should pay attention to unusual changes in their fingernails and toenails. If suspicious signs are noticed, it is advisable to seek medical examination for timely check-up, diagnosis, and treatment if necessary, to limit the risk of complications.

Anh Chi (Compiled)