**Question:** Most common المعدن causing contact dermatitis

**Core Concept:** Contact dermatitis is a skin condition caused by the direct contact with irritants or allergens. Common allergens can lead to allergic contact dermatitis, while irritants cause irritant contact dermatitis.

**Why the Correct Answer is Right:** Nickel is the most common cause of contact dermatitis, particularly in women due to its frequent use in jewelry and fastenings. It primarily affects people with a genetic predisposition, leading to an immune response that results in the characteristic skin symptoms.

**Why Each Wrong Option is Incorrect:**

A. Silver (silver sulfadiazine cream is used for burns, so silver is not the most common cause of contact dermatitis).
B. Gold (although gold alloys can cause contact dermatitis, gold itself is not a common cause)
C. Copper (copper is not the most common cause of contact dermatitis; nickel is)
D. Zinc (zinc oxide is used in medicated ointments and creams, but zinc itself is not the most common cause of contact dermatitis)

**Clinical Pearl / High-Yield Fact:** Nickel allergy is called Nickel Dermatitis. It is essential to identify these cases to prevent unnecessary investigations, such as patch testing, which is required for other allergens like cobalt, thimerosal, and chromium.

**Correct Answer:** C. Copper

In dermatology, it is essential to identify the specific cause of contact dermatitis to initiate appropriate management and prevent unnecessary investigations. In this case, nickel is the most common cause, but identifying copper allergy is crucial as well, as it is a common cause of allergic contact dermatitis, particularly in jewelry and coins.