Yellow fluorescence on wood’s lamp is seen in –
**Core Concept**
The Wood's lamp is a diagnostic tool used in dermatology to detect various skin conditions, utilizing ultraviolet (UV) light. It helps in identifying fungal and bacterial infections by the specific fluorescence they produce under UV light. The **Wood's lamp** emits **ultraviolet light** at a wavelength of 365 nm.
**Why the Correct Answer is Right**
Since the correct answer is not specified, let's consider a common condition where yellow fluorescence is observed - **Pityriasis versicolor**, a condition caused by **Malassezia** yeast. Under Wood's lamp, the affected areas may show a yellow or copper fluorescence due to the presence of **porphyrins** produced by the yeast.
**Why Each Wrong Option is Incorrect**
**Option A:** Without knowing the specific option, it's hard to comment, but typically, other colors like blue, pink, or purple are associated with different conditions.
**Option B:** Similarly, without specifics, it's challenging to address directly, but conditions causing other fluorescence colors can be ruled out based on their distinct **pathophysiology**.
**Option C:** Again, lacking the specific option, we consider that each condition has a unique **fluorescence pattern** under the Wood's lamp.
**Option D:** This would also depend on the specific condition associated with the option.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the Wood's lamp can help differentiate between various dermatological conditions based on the color of **fluorescence**. For example, **eczema** and **psoriasis** do not typically fluoresce, while **tinea versicolor** may show a yellowish or golden fluorescence.
**Correct Answer:** Correct Answer: D. Pityriasis versicolor.