His first job was at University College Hospital as house physician to Sir William Jenner who was in charge of the dermatology department.

[1] In 1863 he published Skin Diseases of Parasitic Origin, in which he was the first physician in the UK to create a thorough study of the pathology and causes of dermatophytosis (ringworm).

At this time, the practice of specialising in medicine was frowned upon in the United Kingdom (although more popular in continental Europe), but Fox and Crocker were credited with bringing some structure to the field of dermatology.

[4] Fox wrote extensively on the subject and in 1875, he published a revised version of Atlas of Skin Diseases by Robert Willan.

[3] William Tilbury Fox died of an aortic condition on 7 June 1879 in Paris, France, at the age of 43.