Differential Diagnosis for a 30-Year-Old Female with Hives and Lymphoid Hypertrophy
Single Most Likely Diagnosis
- Chronic Urticaria: Given the patient's symptoms of hives for two months and the lack of elevated serum IgE or eosinophilia, chronic urticaria is a strong consideration. The presence of large tonsillar hypertrophy and lymphoid hypertrophy could be related to an infectious or autoimmune trigger for the urticaria.
Other Likely Diagnoses
- Infectious Mononucleosis: Although the patient has been on antihistamines for a month, the significant lymphoid hypertrophy, especially in the base of the tongue and vallecula, suggests a possible infectious etiology like mononucleosis, which can cause urticaria and lymphoid enlargement.
- Allergic Reaction: Despite normal IgE levels, an allergic reaction to an unidentified allergen could still be a cause of the hives. The lymphoid hypertrophy might be secondary to chronic antigen exposure.
- Autoimmune Disorders: Conditions like Hashimoto's thyroiditis or rheumatoid arthritis can sometimes present with urticaria and lymphadenopathy, although the latter is more commonly associated with systemic symptoms.
Do Not Miss Diagnoses
- Lymphoma: Although less likely, lymphoma (e.g., Hodgkin lymphoma) can present with lymphadenopathy, including tonsillar hypertrophy, and systemic symptoms like urticaria. It's crucial to rule out lymphoma due to its significant implications for treatment and prognosis.
- Angioedema: While the patient presents with hives, angioedema, particularly if hereditary, could be a consideration, especially if there's a family history. However, the lack of elevated IgE and eosinophilia makes this less likely.
Rare Diagnoses
- Castleman Disease: A rare disorder characterized by lymphoid hyperplasia that can cause lymphadenopathy, fever, and sometimes skin manifestations like urticaria.
- Sjögren's Syndrome: An autoimmune disorder that can present with lymphoid hypertrophy and sometimes cutaneous manifestations, although urticaria is less common.
- Hyper-IgM Syndrome: Although the patient's IgE is normal, certain immunodeficiency syndromes can present with recurrent infections and lymphoid hypertrophy, along with skin manifestations due to immune dysregulation.