Differential Diagnosis
- Single most likely diagnosis
- Wiskott-Aldrich syndrome: This condition is characterized by eczema, thrombocytopenia (low platelet count), and recurrent infections, which aligns with the patient's symptoms, including the erythematous scaly rash, low platelet count (75,000/mm3), and history of frequent infections (otitis media, meningitis).
- Other Likely diagnoses
- Chronic granulomatous disease: This condition is marked by recurrent infections due to the inability of phagocytic cells to kill certain bacteria and fungi. The patient's history of frequent infections and current presentation could fit this diagnosis, although the specific combination of symptoms (rash, thrombocytopenia) is less typical.
- HIV infection: HIV can lead to recurrent infections and failure to thrive, as seen in this patient. However, the specific constellation of symptoms, including the rash and thrombocytopenia, would be less common as a primary presentation of HIV in infancy.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Severe combined immunodeficiency (SCID): Although less likely given the patient's ability to mount some immune response (fever, elevated leukocyte count), SCID is a critical diagnosis not to miss due to its severe prognosis and the need for prompt intervention, such as bone marrow transplantation.
- Thymic-parathyroid dysplasia (DiGeorge syndrome): This condition involves immunodeficiency due to thymic hypoplasia, among other features. While the patient's symptoms do not directly point to DiGeorge syndrome, the history of recurrent infections necessitates considering immunodeficiency disorders.
- Rare diagnoses
- Other immunodeficiency disorders: There are numerous rare immunodeficiency disorders that could present with recurrent infections and other symptoms seen in this patient. These would be considered if more common diagnoses are ruled out.
- Leukocyte adhesion deficiency: This rare condition affects the body's ability to fight infection, leading to recurrent infections, but the specific symptoms and laboratory findings in this case do not directly suggest this diagnosis.