Differential Diagnosis for Itching All Over Body with No Rashes and High Eosinophil Count

Single Most Likely Diagnosis

• Atopic Dermatitis: Although the question mentions no rashes, atopic dermatitis can sometimes present with minimal or no visible skin changes, especially if the patient has been scratching, leading to lichenification. The high eosinophil count supports this diagnosis, as atopic dermatitis is associated with an allergic response and eosinophilia.

Other Likely Diagnoses

• Urticaria: Chronic urticaria can cause itching all over the body and may not always present with visible wheals. Eosinophilia can be seen in some cases, especially those related to allergic reactions.
• Eosinophilic Gastroenteritis: This condition involves the gastrointestinal tract and can cause itching due to the release of histamine and other mediators. Although primarily affecting the GI tract, systemic symptoms including itching can occur.
• Hypereosinophilic Syndrome (HES): A group of disorders characterized by the overproduction of eosinophils, leading to organ damage. Itching can be a symptom, and the high eosinophil count is a key diagnostic feature.

Do Not Miss Diagnoses

• Lymphoma: Certain types of lymphoma, such as Hodgkin lymphoma or cutaneous T-cell lymphoma, can present with itching as a primary symptom, often without a rash. Eosinophilia can be seen in some cases, particularly in Hodgkin lymphoma.
• Cholestasis: Intrahepatic or extrahepatic cholestasis can cause severe itching without a rash. Although eosinophilia is not a hallmark, it's crucial to consider cholestasis due to its potential for severe outcomes if untreated.
• Thyroid Disorders: Both hyperthyroidism and hypothyroidism can cause itching, and while eosinophilia is not typically associated with these conditions, they are important to rule out due to their prevalence and the significant impact of untreated thyroid disease.

Rare Diagnoses

• Eosinophilic Fasciitis: A rare condition characterized by inflammation of the fascia, leading to thickening and hardening of the skin, which can cause itching. Eosinophilia is a key feature, but the condition is very rare and usually presents with skin changes.
• Mastocytosis: A disorder involving the accumulation of mast cells in one or more organs. It can cause itching, flushing, and other symptoms due to the release of histamine and other mediators. Eosinophilia can be seen in some cases.