If your nails turn yellow, the most common cause is onychomycosis (nail fungus). It is recommended that patients visit a dermatology department in a reputable hospital for a proper diagnosis.
If nails grow slowly, lack luster, and become yellow and thick, it often indicates issues with the lymphatic system, such as yellow nail syndrome. Additionally, long-term smokers may have yellow nails due to nicotine staining. As people age, thickened nails can also lead to a lack of shine and a yellowish appearance.
Occasional pinpoint-like dents on the nail surface can be normal, but noticeable dents are often seen in conditions such as psoriasis, alopecia areata, or proximal nail matrix damage due to eczema. Deep, thimble-like dents are common in psoriasis, while small, shallow, geometrically distributed dents are typical in alopecia areata.
Blue nails generally indicate severe hypoxia in heart disease patients, meaning low blood oxygen levels and insufficient oxygen supply to the body, leading to asphyxia or systemic circulation failure, causing blood congestion.
In cases of congenital heart disease, when the disease flares up, inadequate blood supply from the heart can cause the fingernails to turn purple, accompanied by arrhythmias, fatigue, and pale complexion. If the nail color is dull and deep purple and does not improve, it indicates poor blood circulation at the fingertips and suggests the possibility of cor pulmonale or coronary heart disease. It is advisable to seek medical attention promptly.