A 27-year-old sexually active male develops a vesiculobullous lesion on the glans soon after taking tablet paracetamol for fever. The lesion healed with hyperpigmentation. The most likely diagnosis is:
**Core Concept**
The patient is experiencing a vesiculobullous lesion, which is a type of skin reaction involving the formation of blisters, likely caused by an allergic reaction to a medication, in this case, paracetamol.
**Why the Correct Answer is Right**
The patient's symptoms are consistent with an allergic contact dermatitis, a type of skin reaction that occurs when the skin comes into contact with an allergen, in this case, paracetamol. The formation of vesiculobullous lesions and subsequent hyperpigmentation are classic signs of this condition. The reaction occurs due to the release of histamine and other chemical mediators from mast cells, leading to increased vascular permeability, edema, and blister formation.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the patient's symptoms are not consistent with a viral infection, such as herpes simplex, which typically presents with painful vesicles and crusting.
* **Option B:** This option is incorrect because the patient's symptoms are not consistent with a bacterial infection, such as impetigo, which typically presents with crusting and a foul odor.
* **Option C:** This option is incorrect because the patient's symptoms are not consistent with a fungal infection, such as candidiasis, which typically presents with a red, itchy, and scaly rash.
**Clinical Pearl / High-Yield Fact**
Allergic contact dermatitis can occur with a variety of medications, including analgesics, antibiotics, and antihistamines. Patients with a history of allergies or atopic dermatitis are more susceptible to developing this condition.
**Correct Answer:** D. Allergic contact dermatitis.