I have recently been diagnosed with latent tb. I had a mantoux test done 6weeks ago which was very positive. I have seen a chest physcian who started treatment, I have no symptoms of disease. My diagnosis is based on a single mantoux test, is this right? My reaction is 3x4cm, and still growing. It has formed an ulcerating abcess, which produces pus and shows no signs of improving evan after 6 weeks. Swabs showed no bacterial infection. I am on rifampicin and isoniazid at present. O have looked on the Internet to see if anyone else has had a similar reaction but found none, and my gp is also unsure about the abcess. Has anyone heard of such abcess formation after a mantoux? Will it heal byitself?