From Dog
Pale mucous membranes in a Cocker Spaniel with immune-mediated thrombocytopenia[1]
Blood smear of a dog with severe iron deficiency[2]

Anemia is a clinical symptom (rather than specific disease) characterized by pale mucous membranes.

Hematologically, anemia is evidence by low levels of circulating erythrocytes (RBCs) below 15%.

Generally speaking, there are two broad categories of anemia:

  • Regenerative anemia - significant numbers of immature (nucleated) erythrocytes
  • Non-regenerative anemia - reduced numbers or no nucleated reticulocytes

Features of anemia include:

- Anisocytosis with microcytosis - iron deficiency, sickle cell anemia
- Anisocytosis with macrocytosis - Folate or vitamin B12 deficiency, autoimmune hemolytic anemia, cytotoxic chemotherapy, chronic hepatitis, myelolipoma, myelodysplastic syndrome
- Anisocytosis with normocytosis - Early iron, vitamin B12 or folate deficiency, dimorphic anemia, chronic hepatitis, myelodysplastic syndrome
- Microcytic hypochromic anemia - pyridoxine deficiency
- Poikilocytosis, reticulocytosis, stomatocytosis
- Thrombocytopenia

Causes of anemia are numerous, including:

- Aplastic pancytopenia
- Sideroblastic anemia - poikilocytosis, hypersegmented neutrophils and megakaryocytosis
- Myelodysplasia syndrome
- Chronic hepatitis, cholecystitis
- Hemorrhagic gastroenteritis, ulcerative colitis, protein-losing enteropathy
- Chronic renal disease, nephrotic syndrome

Diagnosis is based on blood tests and treatment requires addressing the underlying cause.

Dogs with PCV <15 require blood transfusions.


  1. Pet Place
  2. Naigamwalla DZ et al (2012) Iron deficiency anemia. Can Vet J 53(3):250-256