Q: I am a 26 years old male staying in Bangalore. I have visited Hyderabad thrice, and during all the three visits, I have experienced severe under leg pain. During my first visit, my colleague told me that the drinking water in Hyderabad has more of fluoride and this could be the reason for the pain. So, I avoided drinking tap water and only had mineral water. The pain considerably reduced. After a year, I visited the city for four days and again experienced the pain. On returning to Bangalore, the pain disappeared. Recently, I visited Hyderabad again, avoided the tap water and took all precautions but still experienced the pain. This time the pain was the most severe and I could barely walk. I also noticed slight swelling near my feet. I don't have any other health problems. What could be the possible cause of this pain?

A:From your description, I presume that you have pain in foot and toes. Each time you had the symptoms when you were in Hyderabad and each time it got relieved when you returned back to Bangalore. It seems to be some local factor, which is contributing to this. It could be:

1. A local skin allergy from the soil or any other product that you use there in Hyderabad different from Bangalore. Did you walk bare foot in any carpeted room or in the open?
2. It could be a toilet product that you are using in Hyderabad.
3. It could be an allergy from some dietary constituent, which is different from Bangalore.
4. It is also possible that your long journey may have precipitated swelling on the foot followed by stiffness of the joints and pain. But this would happen in any long journey. Have you noticed that?
5. Have you been staying in air-conditioned rooms in Hyderabad? It is possible; exposure to cold temperature causes painful swellings in hands and feet of some sensitive people. This is because of coagulation of proteins of these people on being exposed to cold. It is typically presents with painful swelling and itching on the toes. This would however, appear in any cold climate not necessarily Hyderabad.