Diagnosis can typically be made from a physical examination of the nail. If necessary, a gram stain or bacteriological culture of nail scrapings can be performed in order to identify the presence of bacteria. There are shortcomings however in conducting a culture because the infection can be present a distance from the nail site, and as a result return a false negative result. A sample of infected nail can be submerged in distilled water to perform a pigment solubility test, within 24 hours the liquid will turn blue<unk>  in colour indicating the presence of Pseudomonas Aeruginosa. Differential diagnosis<unk>  can be misdiagnosed with Aspergillus infections, Malignant melanoma, Subungual hematomas. The use of<unk>  dye, paint or chemical lacquers can also lead to confusion.
Green nail syndrome
Yellow nail syndrome
Blue toe syndrome
Shell nail syndrome
Median nail dystrophy
Elejalde syndrome
Scimitar syndrome
Barraquer–Simons syndrome