Decreased production
Abnormally low platelet production may be caused by:
Dehydration, Vitamin B12 or folic acid deficiency
Leukemia, myelodysplastic syndrome, or aplastic anemia
Decreased production of thrombopoietin by the liver in liver failure
Sepsis, systemic viral or bacterial infection
Leptospirosis
Hereditary syndromesACTN1-related thrombocytopenia
Amegakaryocytic thrombocytopenia with radio-ulnar synostosis
ANKRD26 related thrombocytopenia
Autosomal dominant thrombocytopenia
Bernard–Soulier syndrome (associated with giant platelet disorder)
Congenital amegakaryocytic thrombocytopenia
Congenital amegakaryocytic thrombocytopenia and radioulnar synostosis
CYCS-related thrombocytopenia
Epstein syndrome (associated with giant platelet disorder)
ETV6 related thrombocytopenia
Fanconi anemia
Filaminopathies A
FYB related thrombocytopenia
Glanzmanns thrombasthenia
GNE myopathy with congenital thrombocytopenia
Gray platelet syndrome (associated with giant platelet disorder)
Harris platelet syndrome (associated with giant platelet disorder)
Macrothrombocytopenia and hearing loss
May–Hegglin anomaly (associated with giant platelet disorder)
MYH9-related disease (associated with giant platelet disorder)
PRKACG-related thrombocytopenia
Paris-Trousseau thrombocytopenia/Jacobsen syndrome
Sebastian syndrome
SLFN14-related thrombocytopenia
Stormorken syndrome
TRPM7-related thrombocytopenia
Thrombocytopenia absent radius syndrome
Tropomyosin 4-related thrombocytopenia
TUBB1-related thrombocytopenia
Upshaw–Schulman syndrome
Wiskott–Aldrich syndrome
X-linked thrombocytopenia
X-linked thrombocytopenia with thalassemia

Increased destruction
Abnormally high rates of platelet destruction may be due to immune or nonimmune conditions, including:
Immune thrombocytopenic purpura
Thrombotic thrombocytopenic purpura
Hemolytic–uremic syndrome
Disseminated intravascular coagulation
Paroxysmal nocturnal hemoglobinuria
Antiphospholipid syndrome
Systemic lupus erythematosus
Post-transfusion purpura
Neonatal alloimmune thrombocytopenia
Hypersplenism
Dengue fever
Gauchers disease
Zika virus

Medication-induced
These medications can induce thrombocytopenia through direct myelosuppression:
Valproic acid
Methotrexate
Carboplatin
Interferon
Isotretinoin
Panobinostat
H2 blockers and proton-pump inhibitors

Other causes
Lab error, possibly due to the anticoagulant EDTA in CBC specimen tubes; a citrated platelet count is a useful follow-up study
Snakebite
Niacin toxicity
Lyme disease
Thrombocytapheresis (also called plateletpheresis)
Niemann–Pick disease

Diagnosis
Laboratory tests for thrombocytopenia might include full blood count, liver enzymes, kidney function, vitamin B12 levels, folic acid levels, erythrocyte sedimentation rate, and peripheral blood smear.
Treatment may include a direct thrombin inhibitor, such as lepirudin or argatroban. Other blood thinners sometimes used in this setting include bivalirudin and fondaparinux. Platelet transfusions are not routinely used to treat HIT because thrombosis, not bleeding, is the primary problem. Warfarin is not recommended until platelets have normalized. Congenital amegakaryocytic thrombocytopenia
Bone marrow/stem cell transplants are the only known cures for this genetic disease. Frequent platelet transfusions are required to keep the patient from bleeding to death before the transplant can be performed, although this is not always the case. Human induced pluripotent stem cell-derived platelets
Human induced pluripotent stem cell-derived platelets is a technology currently being researched by the private sector, in association with the Biomedical Advanced Research and Development Authority  and the U.S. Department of Health and Human Services, that would create platelets outside the human body. Neonatal thrombocytopenia
Thrombocytopenia affects a few newborns, and its prevalence in neonatal intensive care units  is high. Normally, it is mild and resolves without consequences. Most cases affect preterm birth infants and result from placental insufficiency and/or fetal hypoxia. Other causes, such as alloimmunity, genetics, autoimmunity, and infection, are less frequent.Thrombocytopenia that starts after the first 72 hours since birth is often the result of underlying sepsis or necrotizing enterocolitis. In the case of infection, PCR tests may be useful for rapid pathogen identification and detection of antibiotic resistance genes. Possible pathogens include viruses (e.g. cytomegalovirus, rubella virus, HIV), bacteria (e.g.