#4 Changes in color
Depending on the precise color, discolored nails that are bluish or green can signify a variety of health issues. According to the AAD, blue nails, for instance, could indicate that you aren’t getting enough oxygen in your circulation, which can occur with a number of illnesses, such as pneumonia or COVID-19.
In some cases, a bacterial infection beneath your nail may cause your fingernail to develop a dark greenish color. Paronychia, the medical term for this condition, can develop if bacteria enter a cut close to the cuticle and spread to the skin beneath the nail.
Yellow staining of the nails is less serious. Patients who suffer from bronchitis and other respiratory problems may experience this condition. Though it occurs more frequently in toenails than fingernails, the fungus can also cause the nails to turn yellow. A nail fungus infection can affect people of any age, but older folks are more susceptible.
