Another symptom of IgA nephropathy is albuminuria—when a person’s urine contains an increased amount of albumin, a protein typically found in the blood, or large amounts of protein in the urine. Albumin is the main protein in the blood. Healthy kidneys keep most proteins in the blood from leaking into the urine. However, when the glomeruli are damaged, large amounts of protein leak out of the blood into the urine.
When albumin leaks into the urine, the blood loses its capacity to absorb extra fluid from the body. Too much fluid in the body may cause edema, or swelling, usually in the legs, feet, or ankles and less often in the hands or face. Foamy urine is another sign of albuminuria. Some people with IgA nephropathy have both hematuria and albuminuria.