Skin pigmentation & icthyosis like side effects are seen in –
**Core Concept**
Skin pigmentation and ichthyosis-like side effects are associated with medications that affect the epidermal cell turnover, melanin production, or lipid metabolism. These effects are commonly seen in drugs that interfere with retinoid signaling pathways or vitamin A metabolism.
**Why the Correct Answer is Right**
The correct answer is associated with the inhibition of retinoic acid metabolism, leading to an accumulation of retinoic acid in the skin. This results in increased differentiation and maturation of keratinocytes, causing thickening of the stratum corneum and scaling (ichthyosis). Additionally, the inhibition of retinoic acid metabolism affects melanin production, leading to changes in skin pigmentation. The correct answer is a medication that inhibits the enzyme CYP26, which is responsible for the metabolism of retinoic acid.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is associated with a medication that affects the sympathetic nervous system, leading to vasoconstriction and increased blood pressure. It does not have any effects on skin pigmentation or ichthyosis.
**Option B:** This option is incorrect because it is associated with a medication that affects the immune system, leading to an increased risk of infections and autoimmune disorders. It does not have any effects on skin pigmentation or ichthyosis.
**Option C:** This option is incorrect because it is associated with a medication that affects the cardiovascular system, leading to an increased risk of myocardial infarction and stroke. It does not have any effects on skin pigmentation or ichthyosis.
**Clinical Pearl / High-Yield Fact**
The use of medications that affect retinoid signaling pathways or vitamin A metabolism can lead to significant changes in skin pigmentation and ichthyosis-like side effects. It is essential to monitor patients on these medications closely for these side effects and adjust the treatment regimen as needed.
**Correct Answer:** C. Etretinate