• Platelets are blood cells involved in the process of healing and blood clotting. In both men and women, a normal count is between 150,000 and 450,000 platelets per microlitre or cubic milimeter of blood, reports Lab Tests Online. A lower count of platelets indicates a condition called thrombocytopenia, which unlike hemophilia, can affect man and women in the same way. Causes of low blood platelets include bone marrow cancer, autoimmune diseases and exposure to some chemical substances.
  
  

Bone Marrow Cancer

• Platelets, as well as other blood cells, are produced in the bone marrow and live for only 10 days. Leukemia and other types of bone marrow cancers can cause a decrease in the production of new platelets, according to Mayo Clinic website. Viral infections, such as AIDS, can also suppress the production of platelets.
  
  

Autoimmune Diseases

• Autoimmune diseases occur when the immune system attacks healthy cells in the body, including platelets. Idiopathic thrombocytopenic purpura (ITP) happens when the immune system destroys the platelets, says the National Heart Lung and Blood Institute. ITP causes severe bruises and bleeding, according to study published in Clinical Advances website. Other autoimmune diseases which destroy platelets include rheumatoid arthritis and lupus, which is characterized by skin rash and joint swelling.
  
  

Exposure to Chemicals

• Exposure to toxic chemicals such as arsenic and benzene, found in some pesticides, can slow the production of platelets, according to the National Heart Lung and Blood Institute. Diuretics, the antibiotic chloramphenicol, aspirin or ibuprofen, as well as other medicines can also affect negatively the production of platelets. Low platelet count can be common among alcoholics leading a iron and vitamin B12 poor diet.