Aplastic anemia is a rare disorder in which the bone marrow as well as the hematopoietic stem cells  that live there are ruined.] This causes a deficiency of all three blood cell types (pancytopenia): red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia). Aplastic describes inability of these stem cells to create bloodcells that are mature.


It's most common in people in their teens and twenties, but can also be common among the elderly. It may result from heredity, resistant disorder, or exposure to chemicals, drugs, or radiation. But in about half the cases, the origin is unknown.
The definitive diagnosis is by bone marrow biopsy; ordinary bone marrow contains 30--70 percent stem cells, but in aplastic anemia, these cells are largely eliminated and replaced with fat.
First line therapy for aplastic anemia contains immunosuppressive medications, usually either anti-lymphocyte globulin or anti-thymocyte globulin, along with corticosteroids and ciclosporin. Hematopoietic stem cell transplantation can be used, particularly for individuals under 30 years of age using a connected paired marrow donor.

Symptoms of Aplastic Anemia

Aplastic anemia symptoms may include:

Fatigue
Shortness of breath with exertion
Rapid or irregular heart rate
Pale skin
Frequent or prolonged infections
Unexplained or easy bruising
Nosebleeds and bleeding gums
Prolonged bleeding from cuts
Skin rash
Dizziness
Headache
Aplastic anemia can progress slowly over weeks or months, or it may come on suddenly. The illness may be brief, or it may become chronic. Aplastic anemia can be very severe and even fatal.

Causes of Aplastic Anemia

Aplastic anemia develops when harm occurs to a bone marrow, slowing or shutting down the creation of new blood cells. Bone marrow is a red, spongy substance within your bones which produces stem cells, which contribute to additional cells. Stem cells from the bone marrow produce blood cells -- red cells, white cells and platelets. In aplastic anemia, the bone marrow is explained in medical terms as aplastic or hypoplastic -- meaning that it is empty (aplastic) or comprises very few blood cells (hypoplastic).

Factors which can temporarily or permanently hurt bone marrow and influence blood cell production comprise:

Radiation and chemotherapy treatments.

Exposure to toxic chemicals.

Use of certain drugs.

Autoimmune disorders.

A viral infection.

Prevention 

There's generally no prevention for most cases of aplastic. Avoiding exposure to insecticides, herbicides, organic solvents, paint removers and other toxic chemicals may lower your risk of the disease.


Source: https://aderonkebamidele.com/aplastic-anemia-causes-signs-symptoms/