HSP can affect different parts of the body and the symptoms vary among different children.
Skin
All children with HSP have purpura, red or purple spots, over their skin, which look like a rash. These spots are usually raised so you can feel them (we say they are palpable). They are usually in groups and symmetrical (they look the same on both sides). The purpura usually appear on the feet and ankles, legs, buttocks, lower back and arms. Children under 2 years may also have purpura on their head, chest and back. Your child may get more purpura as time goes on.
The purpura happens when the small blood vessels under the skin get inflamed and leak blood into the surrounding tissues. It is not contagious, and other people cannot catch purpura by touching your child’s skin.
Your doctor or nurse will give you more information about anything you need to do to. You may wish to speak with staff at your child’s nursery or school about the rash. They may be able to reassure other families that the rash cannot be passed on.
In most children with HSP, the purpura goes away after several weeks, though some will have a rash for a few months or longer. It is rare for the purpura to leave any scars.
Joints
Many children with HSP have pain and/or swelling in their joints. This usually happens in their knees and elbows, and sometimes their ankles and wrists.
In some children, the pain may be severe, and may cause difficulty walking or moving around.
Abdomen
Many children with HSP have abdominal pain (pain in the tummy). This happens when small blood vessels in the lining of the stomach and the intestines (gut) leak blood. Your child may:
- feel sick (nausea) or be sick (vomit)
- have constipation or diarrhoea
- sometimes, have blood or mucus in his or her stools (poo) or vomit.
Other symptoms
- Your child may feel more tired than usual.
- Some boys have orchitis, when the testicle becomes inflamed – this can cause the scrotum to swell up, and become tender and red. If you think this may be happening to your child, take him to your doctor.
Complications: blockage in the bowel
In a few children with HSP, one part of the bowel (intestine) slides into the next part – this is called intussusception. This is like the parts of a telescope folding into each other. The walls of the intestine can press against each other and create a blockage, which can lead to swelling and less blood flowing into the affected areas. It usually happens suddenly.
Children may:
- have severe pain (like colic) every 10–20 minutes – babies or young children may cry and draw up their legs to the chest
- vomit
- feel tired or not be able to concentrate
- pass stools with blood in them – they may look like redcurrant jam or jelly.
Your doctor can diagnose intussusception by doing a physical examination and doing tests, including blood tests and imaging tests (scans). Children with intussusception will need treatment at a hospital. This may be a type of enema (pushing air or liquid into the back passage to cure the blockage) or surgery. Your doctor will give you more information.
Other complications
Very rarely, the brain, or lungs are affected. Children with HSP affecting the brain can appear confused or unresponsive or can have fits (seizures). If the lungs are affected then this can causing bleeding in the lungs. These are very rare and will need treatment in a hospital. If this is the case your doctor will give you more information..
What can happen when HSP affects the kidney?
In about half of children with HSP, the kidneys are affected, leading to the following. These may not happen for some days or weeks after the above symptoms.
- Haematuria (blood in the urine). This happens when red blood cells leak through the kidneys' filters into the urine. Sometimes you cannot see the blood, but if there is a lot, the urine may be coloured red or dark brown (like a cola drink).
- Proteinuria (more protein in the urine than normal). This happens when proteins leak through the kidneys' filters into the urine. You cannot usually see the protein, but it is picked up on a urine test.
- Some children urinate less often or pass smaller amounts.
This is referred to as HSP nephritis (HSP with kidney involvement). This may cause some of the following problems.
High blood pressure
Hypertension, blood pressure that is too high, can occur in HSP nephritis. There are often no symptoms, though some children develop headaches, vomiting or blurred (fuzzy) vision. Hypertension that lasts a long time can also increase the risk of getting other diseases in adulthood.
These children will need to control their blood pressure so it is in the healthy range. They may need to reduce the amount of salt they eat or make other changes to their diet. Some children take medicines to help control their blood pressure.
Swelling in the body
Some children with HSP nephritis get swelling or puffiness in different parts of the body, especially around their eyes, legs and feet – this is called oedema.
In HSP, the kidneys sometimes leak a large amount of one type of protein – especially a type called albumin – into the urine, and so there is not enough in the body. Albumin helps fluid (water) move in and out of the bloodstream, so that the body’s cells can be nourished, or fed. When there is not enough albumin in the blood, the fluid cannot move back into the bloodstream. The fluid stays in parts of the body, and this causes the swelling. When this happens it is called nephrotic syndrome.
Rapidly progressive glomerulonephritis
Very rarely, the kidney problems get worse quickly – this is called rapidly progressive glomerulonephritis or crescentic glomerulonephritis.
This may lead to acute kidney injury (AKI) – when the kidneys stop working over a short time. Some children get better after a few weeks, and some need to take medicines or have more intensive treatment.