This patient has modest eosinophilia. In view of the past history of thyroiditis,  an underlying autoimmune disorder may still be a possibility. Because of his symptoms (pronounced fatique and tiredness), I would do a CT scan of chest, abdomen and pelvis to exclude underlying LPD (Hodgkins/NHL..). I would also do a marrow aspirat/ biopsy and carry out FISH/PCR for BCR-ABL, JAK2 mutation and FIP1L1-PDGFR fusion analysis. Good luck

I guess your Haematologist must have ruled out HES and CML, using molecular techniques.

I guess it is a seasonal allergy to pollen or anything he eat that he sensitive to it like food allergen, I think you should see his diet plan, or see what he wear it may be allergy to some substance in his clothes.

Why not think about allergic process? The patient have a eosinophilia.near normal values 0,50 x [10.sup.9]/L). Hypereosinophilic syndrome is out of the question!!!

I agree completely with Dr. Muttuswamy. 

The informations provided by Dr. Savan do not include objective or subjective manifestations of allergy in the absence of which the only hypereosinophilia is not enough. The exclusion of hematological diseases seems hasty: were not made the instrumental and laboratory investigations.I think you should follow two paths: 

 My final consideration is a question: why we continue to use the so called "tumor markers" for diagnostic purposes? In my opinion this is a serious professional inappropriateness.

Instead bone marrow aspirat/ biopsy and other expensive and invasive examinations. why not start with the peripheral blood smear observation? I only ear something about 17% of  eosinophils counted by a machine? Why fatique and tiredness have to be with eosinophilia? Secondary to medication?  hypertension or heart problems?

I think you excluded some causes like: Parasitic disease and Connective tissue disease , but in this case i think it is important to differentiation between destruction-induced thyrotoxicosis, Graves' thyrotoxicosis and subacute thyroiditis with hyperthyroidism. Hypereosinophilia is increased in Graves' thyrotoxicosis

Other causes must be excluded: Allergic diseases e.g asthma, hay fever, eczema, pulmonary hypersensitivity reaction ― e.g Loeffler’s syndrome’,

Skin diseases, e.g psoriasis, drug rash , and Drug sensitiviry

Also Bone marrow to exclude: Hematological malignancy e.g lymphomas, Eosinophilic leukemia, Idiopathic hypereosinophilia

Myelproliferative disorders, chronic myeloid leukemia, polycythemia vera, myelofibrosis

Given that parasitic diseases and hematological malignancies are ruled out, since the AgE levels are high, I would suspect Primary immunodeficiency disorder.  In my opinion it could be HyperIgE syndrome or Omenn syndrome.

Repeat the test to see if eosinophilia is persistent.

In a first stage rule out allergies and parasitic infections.

Would add a chest x-ray and ultrasound of abdomen.

In a second stage if eosinophilia is maintained Increases or would do studies and molecular tomography.

I evaluated critically my and other answer regarding the Veaceslav's question.

This is an incomplete list of diseases proposed by us to understand a (modest!) eosinophilia: chronic lymphoproliferative diseases; Hodgkins/NHL; myeloprolipherative neoplasms including Hypereosinophilic syndrome; allergy to pollen or food; hypertension; heart problems; Graves' thyrotoxicosis; sub-acute thyroiditis; asthma; hay fever; eczema; pulmonary hypersensitivity reaction; Loeffler’s syndrome; psoriasis, drug rash , and drug sensitivity; primary immunodeficiency disorder; hyper-IgE syndrome; Omenn syndrome; solid neoplasms; parasitic infection.

These are the diagnostics test proposed; bone marrow examination; FISH/PCR for BCR-ABL, JAK2 mutation and FIP1L1-PDGFR fusion analysis; chest x-ray and ultrasound of abdomen; molecular tomography.

Based on the excellent clinical history provided by Veaceslav, the "patient" now is asymptomatic. In addition, many of proposed diagnostic tests were already performed. We must therefore ask ourselves if we're not risking turning a symptom in a disease. We must also ask ourselves whether, in our assessments and proposals, we evaluated the economic and non-economic costs.

Do you thought that most likely all proposed tests are negatives?. (An Italian proverb says: finding a needle in a haystack!)

We thought that it would worsen the quality of life of this man if we force him to the diagnostic processes that we proposed.

Sorry for these words! I think it's ethical to propose to this man (as long as it is asymptomatic) only a careful but not obsessive surveillance.

Thanks Dr Antonio La Gioia  for a development of my question.

The same questions we ourselves. The patient is young, not feeling well, he put many questions to which we can not give a concrete answer. The other day I made a TDM chest and abdomen, but again I have not found anything.

Thanks to all colleagues who were actively involved in this interesting discussion. If you have other ideas, I'll take them into consideration with the greatest pleasure.

First, some additional informations should be relevant:

1. A list of currently used drugs

2. History of allergy?

3. Trip outside the US?

4. Any PET at home?

5. Professional exposure ?

Anyway, the amont of blood eosinophils is not very impressive and far from the range ususally observed in diseases such as eosinophilic leukemia, T-cell lymphoma, vasculitis or hypereosinophilic syndrome. Without a firm diagnosis, a watch and wait attitude is a reasonable choice.

It looks as though eosinophilia could be associated with immune/allergic condition - thyroiditis (presumably lymphocytic, Hashimoto thyroiditis). Unclear if he was tested for FIP1L1 mutation but I would expect higher eosinophil counts. Drugs are often cited as cause of eosinophilia but I am not aware of any being singled out (except Clozapine).

I have patients with much higher "idiopathic" EOS counts (2.0-4.0) with no symptoms, whom I just monitor.

In case of excluding secondary causes clonal eosinophilia and chronic eosiniphilic leukemia should be considered and PDGF as  well as FGF should be done 

I think I would watch and wait with that degree of eosinophilia.  Exclude Coeliac Disease and Sarcoidosis, which are other causes of Eosinophilia.