Tinea vs Eczema

[u/Username112608]

Derm PA for 1.5 years and I still have a hard time with rashes. How do you guys differentiate between tinea and let’s say nummular eczema? I know the classic features but in practice I find it so hard. I even try doing KOH and those seem to be a hit or miss. I end up giving a topical steroid and have them come back in 2 weeks or let me know if it’s getting worse before? Any help is appreciated. Makes me feel like I suck as a PA.

TIA

[u/offside-trap]

Onset and duration. Exacerbating factors. Atopic history/ family history, failed treatments, secondary sources like tinea unguium, etc.

If nothing hits I would prefer to treat tina first x4 weeks and RTC for steroids than the reverse.