Answered by Shaykh Abdurrahman ibn Yusuf Mangera
I have a medical condition in which blood and other liquids are passed out of my leg. Because of this I have difficulty keeping wudu, as the liquids are flowing continuously; my clothes are affected around the medical area. As I am at work I cannot change my clothes, hence the question what should I do when my clothes are affected by the blood and puss?

Assalamu alaykum
In the name of Allah the Inspirer of truth
In a situation where one is considered an excused [madhur] person [please search archives for related rulings] there is some concession made for praying with impurity on the clothing or body. However, this is when a person is unable to clean the affected area, change, and find enough time to pray before the bleeding occurs again. If there is some way of stopping the bleeding, or at least reducing the flow, then those measures should be taken.
The great Syrian jurist Allama Midani explains that if for instance praying sitting down ebbs the flow of blood then it is best to forgo the bowing and prostration and pray with gestures than to pray with impurity on the clothing (Al-Lubab fi Sharh al-Kitab).
In your case, you should place a heavy bandage or some form of covering if possible) on the affected area to help keep your clothing from being soiled. A spare pair of trousers which you change into for prayer may be advisable, after which you can change back into your regular cloths. If, however, nothing stops the impurity from spreading, nor does changing help, then you can pray with the soiled clothing on.
And Allah knows best.
Wassalam
Abdurrahman ibn Yusuf