6 yr old child presented to OPD with eczematous rash On evaluation was found to have fever platelests 80,000 on enquiry multiple hospitalisation for recurrent infections
**Core Concept**
The child's presentation of recurrent infections, eczematous rash, and low platelet count suggests an underlying immune deficiency disorder, specifically a form of Primary Immunodeficiency (PID). The most likely condition is Common Variable Immunodeficiency (CVID) or another PID that affects cellular immunity, such as Wiskott-Aldrich Syndrome (WAS).
**Why the Correct Answer is Right**
The child's symptoms of recurrent infections, eczematous rash, and low platelet count are characteristic of Wiskott-Aldrich Syndrome, a rare X-linked recessive disorder caused by mutations in the WAS gene. This gene encodes for the WAS protein, which is essential for signaling in T cells and platelets. The resulting immune dysfunction leads to increased susceptibility to infections, eczema, and thrombocytopenia (low platelet count). The WAS protein deficiency affects the functioning of T cells, leading to impaired cellular immunity.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specifically address the child's symptoms of recurrent infections, eczematous rash, and low platelet count. While atopic dermatitis (eczema) can be a feature of other immune disorders, the combination of symptoms in this child is more suggestive of Wiskott-Aldrich Syndrome.
**Option B:** This option is incorrect as it does not accurately describe the child's condition. DiGeorge Syndrome is a different primary immunodeficiency caused by thymic hypoplasia and parathyroid gland aplasia, leading to T cell deficiency and hypocalcemia.
**Option C:** This option is incorrect as it does not directly address the child's symptoms. Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by defects in the NADPH oxidase complex, leading to impaired phagocytic killing of catalase-positive bacteria.
**Option D:** This option is incorrect as it does not accurately describe the child's condition. Selective IgA deficiency is the most common primary immunodeficiency, characterized by low levels of IgA antibodies. While it can increase the risk of infections, it does not typically present with eczematous rash or low platelet count.
**Clinical Pearl / High-Yield Fact**
Wiskott-Aldrich Syndrome is a rare but classic example of a primary immunodeficiency disorder that affects both cellular and humoral immunity, leading to increased susceptibility to infections, eczema, and thrombocytopenia.
**Correct Answer:** C. Wiskott-Aldrich Syndrome.