A 7 years old boy presented with painful boggy swelling of scalp, multiple sinuses with purulent discharge, easily pluckable hairs and lymph nodes enlarged in occipital region. Which one of the following would be most helpful for diagnostic evaluation?
**Core Concept**
The patient's presentation is suggestive of a scalp infection, likely folliculitis or furuncles, which may have progressed to a more severe condition such as carbuncles or hidradenitis suppurativa. The presence of boggy swelling, multiple sinuses, and purulent discharge points towards a deep-seated infection involving the hair follicles.
**Why the Correct Answer is Right**
The most helpful diagnostic evaluation would be a **Complete Blood Count (CBC)**, including a differential count, to assess for signs of infection or inflammation. This would help identify any potential underlying conditions such as neutropenia, which could predispose the patient to severe infections. Additionally, a CBC can provide information on the patient's overall health status and help guide further management.
**Why Each Wrong Option is Incorrect**
**Option A:** A **Skin biopsy** may be helpful in cases where the diagnosis is unclear or if there is suspicion of a more complex condition such as hidradenitis suppurativa, but it is not the most helpful initial diagnostic test.
**Option B:** A **Chest X-ray** may be indicated if there is suspicion of a systemic infection or if the patient has a history of respiratory symptoms, but it is not directly relevant to the scalp infection.
**Option C:** A **Liver function test (LFT)** may be indicated if there is suspicion of a systemic infection or liver involvement, but it is not the most helpful initial diagnostic test for a scalp infection.
**Clinical Pearl / High-Yield Fact**
A boggy swelling of the scalp is often associated with a deeper infection, such as a carbuncle, which can spread to the lymph nodes and cause significant morbidity.
**Correct Answer:** C.