If 4 physicians cannot come up with a diagnosis, it is unlikely that I can come up with anything new without examining the patient.
Infection needs to be ruled out - culturing the urethral for bacteria and yeast should be done. Antibiotics for bacteria, or an antifungal for a fungal infection, can be considered if present.
If infection has been appropriately evaluated for, you can consider stronger corticosteroids to treat for a dermatitis. A referral to a dermatologist can be considered to evaluate this possibility.
You can consider another opinion at a major academic medical center if the workup remains non-revealing.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
kevinmd_b