In medicine, if it walk like a horse and talks like a horse, it’s a horse. You don’t start looking into the health of relatives when your patient tells the full story on their own.

Sickle cell anemia is common among African Americans (if you don’t have the full-blown version, the genes can assist with resisting one of the common mosquito-borne diseases found in Africa, which is why it developed in the first place I believe).

So, we have a patient in the primary risk group presenting with symptoms that match well with SCA. You treat that now, unless you have a specific reason not to.

Sometimes you have a list of 10-ish diseases in order of descending likelihood, and the only way to rule out which one it isn’t, is by seeing no results from the treatment.

Edit: and it’s probably worth mentioning no patient ever gives ONLY relevant info. Every human barrages you with all the things hurting that may or may not be related. A doctor’s specific job in that situation is to filter out useless info.