Platelets help clot your child's blood, and a normal platelet count ranges between 150,000 to 400,000 platelets per microliter (mcL). When a platelet count is below normal, it's called thrombocytopenia; when the count is above normal, it's referred to as thrombocytosis. Have your doctor order a platelet count for your child if you notice trouble clotting, abnormal bleeding or bruising without explanation of what caused them. If your child's platelet count comes back abnormal, your doctor should ask questions and run tests to rule out diseases and conditions that could be a cause for the abnormal platelet count.
Chediak-Higashi Syndrome
Chediak-Higashi syndrome can cause a low platelet count. This syndrome affects the immune system by damaging the cells that make up the system, which leaves them unable to effectively fight off viruses and bacteria. Children with Chediak-Higashi syndrome have infections starting in infancy or early childhood, which tend to be very serious. Few people with this condition live to adulthood. If people with Chediak-Higashi syndrome live to be adults, they may have problems with their nervous system that cause weakness, clumsiness, difficulty with walking and seizures.
Hermansky-Pudlak syndrome
Hermansky-Pudlak syndrome causes abnormal platelet function. It's characterized by a low immune system, abnormal bruising, abnormal bleeding and clotting issues, and is accompanied by oculocutaneous albinism. This condition causes abnormally light pigmentation of the skin, hair and eyes. Extensive sun exposure causes skin damage and skin cancers for children who have oculocutaneous albinism. Other problems that occur in affected children include reduced pigment of the iris and reduced tissue at the retina, which causes vision problems such as reduced sharpness, rapid and involuntary eye movements and increased sensitivity to light.
Hemophilia
Hemophilia is a disorder that slows the blood clotting process. It's an example of abnormal functioning platelets and involves a deficiency in one of the12 factors that are imperative to the clotting process. There are two main types of hemophilia: hemophilia A and hemophilia B. It's estimated that hemophilia A occurs in 1 of 5,000 males, while hemophilia B occurs in approximately 1 of 20,000 newborn males. If a child has a milder form of this disorder, it may not be discovered until abnormal bleeding after surgery or a serious injury occurs.
Wiskott-Aldrich Syndrome
Wiskott-Aldrich syndrome occurs between 1 and 10 times per million males born worldwide. This syndrome causes a decrease in the number and size of platelets in a child's body. The platelet abnormality is typically present at birth and can lead to eczema, bruising and prolonged bleeding following trauma. Children with Wiskott-Aldrich syndrome are at an increased risk of infection due to dysfunction of many types of immune cells, such as T cells and B cells.
Thrombocytopenia Absent Radius Syndrome
When a child is born without her radius bone in her forearm, the doctor tests her for thrombocytopenia-absent radius syndrome. This syndrome is characterized by platelet deficiency during infancy, but the deficiency lessens over time. Episodes of severe bleeding may occur in the brain and other organs during her first year of life. Children who survive the first year of life without brain damage live a relatively normal life.
