Red urine may not always be haematuria.
Some foods, such as beetroot, can make the urine look red. Some medicines (including rifampicin, nitrofurantoin and senna) can also make the urine red.
Girls who have their menstrual period may sometimes see blood when they urinate.
Occasionally, there are other reasons that urine is a different colour than usual. Your child’s doctor or nurse will check for these.
Transient (temporary) haematuria
Sometimes children leak a small amount of blood in the urine for a short period of time. This does not usually mean there is a problem, especially if:
- it happens after lots of exercise
- there is irritation in the genital area
- the blood is not visible and it goes away when checked again
A common cause of macroscopic haematuria (where there is visible blood) in children is a urinary tract infection (UTI), when germs get into the urine and travel up the urinary system. The haematuria usually disappears after the child gets better.
Surgery
After some types of surgery, blood may get into the urinary system. Your surgeon or doctor will give you more information on this.
Conditions that can cause haematuria
Urethritis - the inflammation of the urethra, usually found in teenage boys.
Glomerulonephritis - a group of conditions that cause inflammation in the glomeruli, the blood vessels in the kidneys’ filters. Children with these conditions may have blood and protein in their urine. In severe cases they may also have swelling around their face and legs.
Alport syndrome - a very rare genetic condition.
IgA Vasculitis/IgA nephritis - conditions where the body's immune system causes the kidneys, and in some cases the blood vessels in the skin and joints, to become inflamed.
Post-infectious glomerulonephritis (PIGN). This condition happens in some children after they get an infection – usually in the throat, nose or sinuses, or the skin. A few weeks later, the immune system, which normally protects the body from infections and disease, causes inflammation (swelling) in the kidneys. This leads to PIGN. In most cases this gets better by itself without the need for treatment.
Kidney and bladder stones - small crystals, or clumps of hard material, that form in the kidney or bladder. They can cause pain when urinating. They are rare in children.
Blood clots (or thromboses) are clumps that form when the blood hardens.
- Kidney vein thrombosis causes clots in the renal vein, the blood vessel that brings blood to the kidneys. This condition is most common in newborn babies who need an umbilical venous catheter. This is a flexible tube that is placed into the vein in the umbilical cord (where the tummy button is).
- Blood disorders where the blood does not clot properly or clots too easily, such as haemophilia or sickle cell disease.
Thin basement membrane nephropathy is a rare condition that can run in families. One layer of the glomerulus does not form properly and allows red blood cells to leak into the urine. This layer can look thinner than usual when looked at under a very high-power microscope. It does not usually cause long-term problems.