24 hours after fever, maculopapular rash and erythema appears on the face of infant.  This organism can also cause
It’s caused by Parvo B19 virus, and it causes the following diseases

Erythema infectiosum
Fifth disease.
Slapped cheek appearances.
Arthropathy.
Transient Aplastic crisis.
Hydrops fetalis (most sensitive period 2nd trimester)
Myocarditis.
PPGSS
Papular - Purpuric Gloves & Stock Syndrome.

 
Transient Aplastic Crisis

The transient arrest of erythropoiesis and absolute reticulocytopenia.
RBC aplasia or transient aplastic crisis in patients with chronic hemolytic conditions, including:


Sickle cell disease.
Thalassemia.
Hereditary spherocytosis.
Pyruvate kinase deficiency.


In contrast to children with erythema infectiosum only, patients with aplastic crisis are ill with fever, malaise, and lethargy and have signs and symptoms of profound anemia, including pallor, tachycardia and tachypnea.
The incubation period tor transient aplastic crisis is shorter than that for erythema infectiosum because the crisis occurs coincident with the viremia.
Children with sickle cell disease may also have a concurrent vasoocclusive pain crisis.
ALL
CML
Pure red cell aplasia
Hairy cell leukemia