**Core Concept**
Volkmann's Ischaemic Contracture is a condition caused by acute ischaemia of the forearm muscles, often resulting from a supracondylar fracture of the humerus or a tight cast. This condition leads to muscle necrosis and subsequent contracture. It is essential to recognize the early symptoms to prevent long-term damage.

**Why the Correct Answer is Right**
The earliest symptom of Volkmann's Ischaemic Contracture is pain out of proportion to the injury. This occurs due to the accumulation of lactic acid and other metabolites in the ischaemic muscles, leading to pain and discomfort. The pain is often described as severe, constant, and unrelenting. As the condition progresses, the patient may experience numbness, tingling, or weakness in the hand, but the initial symptom is pain.

**Why Each Wrong Option is Incorrect**
* **Option A:** Numbness in the hand - While numbness and tingling can occur in Volkmann's Ischaemic Contracture, they are not the earliest symptom. Numbness is a result of nerve compression due to muscle swelling.
* **Option B:** Swelling of the forearm - Swelling is a common feature of many injuries, including fractures and soft tissue trauma. However, it is not a specific indicator of Volkmann's Ischaemic Contracture.
* **Option C:** Decreased pulse in the forearm - A decreased pulse in the forearm can indicate ischaemia, but it is not the earliest symptom of Volkmann's Ischaemic Contracture. A decreased pulse may not always be present, especially in the early stages.

**Clinical Pearl / High-Yield Fact**
Remember that the "6 P's" of Volkmann's Ischaemic Contracture are: Pain, Pallor, Pulselessness, Paraesthesia (numbness or tingling), Poikilothermia (coldness to touch), and Paralysis. Early recognition of these symptoms is crucial to prevent long-term damage.

**Correct Answer: A. Pain out of proportion to the injury.**