You can just use Unicode italics (assuming you have a font that covers these characters):
text("Relative abundance of 𝘌. 𝘤𝘰𝘭𝘪")
(In Julia, type by tab-completing \itE, \itc, etcetera. You could easily write a function that converts ASCII letters in a string to their Unicode italic, bold, etcetera equivalents, but the web site linked above is also pretty convenient.)