An adult presents with oval scaly hypopigmented macules over chest and back. The diagnosis is:
## **Core Concept**
The question presents a clinical scenario involving a patient with oval, scaly, hypopigmented macules located on the chest and back. This description suggests a dermatological condition. The key to solving this question lies in recognizing the characteristic skin lesions and their typical distribution.
## **Why the Correct Answer is Right**
The correct answer, **Pityriasis versicolor**, is a common superficial fungal infection caused by *Malassezia* species. It presents with oval or round, scaly, hypopigmented or hyperpigmented macules, typically on the chest and back. The lesions are often described as being "spaghetti and meatballs" under the microscope due to the combination of hyphae and yeast cells. The condition is more noticeable in summer when the surrounding skin tans, making the lesions appear lighter.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not correspond to the correct diagnosis based on the description provided. Without the specific details of option A, we can infer it's not Pityriasis versicolor.
- **Option B:** Similarly, this option does not match the clinical presentation of oval, scaly, hypopigmented macules on the chest and back.
- **Option D:** This option is also incorrect as it does not align with the diagnosis of Pityriasis versicolor.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl for Pityriasis versicolor is that the skin scrapings of the lesions, when examined under a microscope with potassium hydroxide (KOH) preparation, show a characteristic "spaghetti and meatballs" appearance due to the presence of both hyphae (spaghetti) and yeast cells (meatballs). This condition is more common in warm and humid climates and can be treated with topical antifungals.
## **Correct Answer:** . Pityriasis versicolor