Immune thrombocytopenia

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Immune thrombocytopenia is a disorder characterized by a blood abnormality called thrombocytopenia, which is a shortage of blood cells called platelets that are needed for normal blood clotting.

Affected individuals can develop red or purple spots on the skin caused by bleeding just under the skin's surface. Small spots of bleeding under the skin are called purpura and larger spots are called ecchymoses. People with immune thrombocytopenia can have significant bleeding episodes, such as nose bleeds (epistaxis) or bleeding in the moist lining (mucosae) of the mouth. In severe cases, individuals may have gastrointestinal bleeding or blood in the urine or stool, or heavy and prolonged menstrual bleeding (menorrhagia). In very rare instances, bleeding inside the skull (intracranial hemorrhage) can occur, which can be life-threatening. A greater reduction in platelet numbers is often associated with more frequent bleeding episodes and an increased risk of severe bleeding.

While immune thrombocytopenia can be diagnosed at any age, there are two periods when the condition is most likely to develop: early childhood and late adulthood. In children, the reduction in platelets is often sudden, but platelet levels usually return to normal levels within weeks to months. Immune thrombocytopenia in children is often preceded by a minor infection, such as an upper respiratory infection, but the relationship between the infection and immune thrombocytopenia is not clear. In adults, the development of immune thrombocytopenia is usually gradual and the condition tends to persist throughout life.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The genetic cause of immune thrombocytopenia is unclear. This condition occurs when the body's own immune system malfunctions and attacks the body's tissues and organs (autoimmunity). Normally, the immune system produces proteins called antibodies, which attach to specific foreign particles and germs, marking them for destruction. In immune thrombocytopenia, the immune system abnormally destroys platelets and makes fewer platelets than normal. People with immune thrombocytopenia produce antibodies that attack normal platelets. The platelets are destroyed and eliminated from the body, resulting in a shortage of these cells in affected individuals. Some of these antibodies also affect the cells in the bone marrow that produce platelets (known as megakaryocytes), which leads to a decrease in platelet production, further reducing the number of platelets in the blood.

In some people with immune thrombocytopenia, the abnormal immune reactions may coincide with an infection by certain viruses or bacteria. Exposure to these foreign invaders may trigger the body to fight the infection, but the immune system also mistakenly attacks platelets.

Genetic variations (polymorphisms) in a few genes have been found in some people with immune thrombocytopenia and may increase the risk of abnormal immune reactions. However, the contribution of these genetic changes to the development of immune thrombocytopenia is unclear.

When the condition is due to the targeted destruction of platelets by the body's own immune cells, it is known as primary immune thrombocytopenia. Immune thrombocytopenia following bacterial or viral infection is considered primary because the infection triggers a platelet-specific immune reaction, typically without any other signs or symptoms. However, immune thrombocytopenia can be a feature of other immune disorders, such as common variable immune deficiency, which occurs when the immune system has a decreased ability to protect the body against foreign invaders, or other autoimmune disorders such as systemic lupus erythematosus. Immune thrombocytopenia can also occur with other blood disorders, including a form of cancer of the blood-forming tissue known as chronic lymphocytic leukemia, and human immunodeficiency virus (HIV) infection. When immune thrombocytopenia is a feature of other disorders, the condition is known as secondary immune thrombocytopenia.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Immune thrombocytopenia and other autoimmune disorders can run in families, but the inheritance pattern is usually unknown. People with a first-degree relative (such as a parent or sibling) with immune thrombocytopenia likely have an increased risk of developing the disorder themselves.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

The incidence of immune thrombocytopenia is approximately 4 per 100,000 children and 3 per 100,000 adults. In adults with immune thrombocytopenia, women are affected more often than men.

It is likely that this condition is underdiagnosed because those with mild signs and symptoms often do not seek medical attention.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Thrombocytopenia · Very frequent (99-80%)

A reduction in the number of circulating thrombocytes.

Anti-glutamic acid decarboxylase antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the serum that react against glutamic acid decarboxylase.

Anti-insulin antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the serum that react against insulin.

Anti-islet antigen-2 antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the serum that react against tyrosine phosphatase IA-2.

Anti-platelet antigen antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the serum that react against antigens present on the surface of thrombocytes such as the glycoproteins GPIIb/IIIa, GPIb/IX, and GPIa/IIa.

Anti-thyroglobulin antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the serum that react to thyroglobulin.

Anti-thyroid peroxidase antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the serum that react against thyroid peroxidase.

Anti-thyroid-stimulating hormone receptor antibody positivity · Frequent (79-30%)

The presence of autoantibodies (immunoglobulins) in the serum that react against thyroid-stimulating hormone.

Other findings in the same source

From: Orphanet

Additional reported features include Arterial thrombosis (Frequent (79-30%)); Liver kidney microsome type 1 antibody positivity (Frequent (79-30%)); Petechiae (Frequent (79-30%)); Purpura (Frequent (79-30%)); Abnormal vaginal bleeding (Occasional (29-5%)); Bruising susceptibility (Occasional (29-5%)); Epistaxis (Occasional (29-5%)); Gastrointestinal hemorrhage (Occasional (29-5%)); Gingival bleeding (Occasional (29-5%)); Hematuria (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Immune thrombocytopenia is Haematology, with a haematologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which blood-cell, marrow, bleeding or clotting finding matters most?
• Does the diagnosis need confirmation or a more precise subtype?
• Which symptoms or laboratory changes should trigger earlier review?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Immune thrombocytopenia. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.