Primarily towards WW1 and WW2 but how were soldiers with gout treated?

Concerning the U.S. Army during World War II, the answer to this question is relatively simple. Regulations concerning gout were found in the "endocrine and metabolic disorders" section of Mobilization Regulations No. 1-9, the War Department pamphlet which governed the medical standards that civilians had to meet in order to be considered for service during the period of U.S. involvement in WWII. MR 1-9 was first promulgated on 31 August 1940, superseding MR 1-5 first issued in 1932, with new amended editions being issued on 15 October 1942 and 19 April 1944.

in all editions, pre-existent gout was permanently disqualifying for all military service, and would likely result in a disability discharge under Section II, AR 615-360 (certification that an enlisted man has become unfit for service because of a physical disability) if contracted while in service.

Mobilization Regulations No. 1-9, 31 August 1940, Section XVII, Endocrine and Metabolic Disorders:

71.) Class 4.- [disqualifying for military service] k. Gout.

Mobilization Regulations No. 1-9, 19 April 1944, Section XVIII, Endocrine and Metabolic Disorders:

83.) Nonacceptable.- m. Gout.

Source:

Foster, William B., Ida Levin Hellman, Douglas Hesford, and Darrell G. McPherson. Medical Department, United States Army in World War II: Physical Standards in World War II. Washington, D.C.: Office of the Surgeon General, Department of the Army, 1967.