Based on the information it seems
The problem is SOME WHERE IN THE STEM CELLS which produces the PLATELET CELL STREAM as the other CELL linage like leukocytes
and the red cell are normal as per the given information , as well as do not had any viral fevers like dangue so,.
Probable diagnosis : - selective PLATELET production problem.
The big size platelet and short life platelet is mostly associated with
1) Low, THROMBOPOIETIN
- production from liver (required to stimulate the growth of platelet).
2) Low, vitamin B12& FOLIC ACID
(required to proper production of platelet).
3) Bernard–Soulier syndrome - lack of "glycoprotein Ib "- genetic disorder
4) May–Hegglin anomaly- rare genetic disorder.
5) Congenital amegakaryocytic thrombocytopenia
- genetic disorder.
***** FURTHER Investigation needs to be done
a) Bone marrow
biopsy to check any genetic disorder,
b) blood test
to check levels of other factors
c) check for infection present.
***** CONSULT -HEMATOLOGIST
Now the treatment option varies with the cause
1) Replace THROMBOPOIETIN if low.
2) give vitamin B12, and folic acid if low
3) lithium carbonate and folic acid stimulates the platelet production
4) need platelet transfusion if above mention steps do not work
5) last and final option is "BONE MARROW TRANSPLANT"
HOPE IT HELPS