The other day, I'm seeing a diabetic patient in clinic, and they have onychauxis. Then I see that they also have Hallux Limitus - Dr Hurly pops into my head - check for subungual ulceration! Well that case turns out to be nothing... But just today I am reading Podiatry Today - March 2012 - How to Address Onychomycosis in Patients with Diabetes - and behold page 2 discusses: "If the patients are fortunate, one will discover the ulcer at the time of the regular debridement of the nail but this happens if and only if the caseous material of an onychomycotic nail receives aggressive debridement. The physician who decides to limit his or her debridement to the length of the nail and top several layers of onychomycotic nail may miss the presence of an ulceration completely. Another clue to the presence of a subunugal ulceration in a patient with diabetes is the presence of hallux limitus with a thickened nail. Boffeli and colleagues found this biomechanical abnormality along with the deforming nail to have caused four uclers. " There you have it - while it isn't peer reviewed, Drs. Brett Waverly and Kathleen Satterfield agree that thickened nails in diabetics with hallux limitus should be carefully watched for ulcers developing under the hallux nail. In order to find this, though, you must debride enough of the nail to see it. -Boffeli, Bean, natwick. Biomechanical abnormalities and ulcers of the great toe in patients with diabetes. JFAS 2002; 41(6): 3359-364.