Drug-Induced Pigmentary Changes Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Drug-Induced Pigmentary Changes. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Drug-Induced Pigmentary Changes Indian Medical PG Question 1: All of the following drugs cause amorphous whorl like corneal deposits except:
- A. Chlorpromazine
- B. Amiodarone
- C. Chloroquine
- D. Indomethacin (Correct Answer)
Drug-Induced Pigmentary Changes Explanation: ***Indomethacin***
- While indomethacin can cause various ocular side effects, **corneal deposits** are not typically described as the **amorphous whorl-like type** seen with the other listed drugs.
- Ocular side effects of indomethacin more commonly include **corneal opacities** and **retinal changes** but not the specific **"cornea verticillata"** pattern.
*Chlorpromazine*
- **Chlorpromazine** can cause **corneal and lenticular deposits**, but these are typically described as **fine granular or stellate deposits** rather than the classic whorl pattern.
- While these deposits can accumulate in the corneal epithelium, they do not characteristically present with the **"cornea verticillata"** (whorl keratopathy) pattern seen with amiodarone and chloroquine.
- The deposits are generally benign but can lead to visual disturbances.
*Amiodarone*
- **Amiodarone** is a classic cause of **cornea verticillata**, or **whorl keratopathy**, with amorphous, whorl-like deposits in the corneal epithelium.
- These deposits occur in **>90% of patients** on long-term therapy and are typically benign and rarely affect vision.
- The whorl pattern is highly characteristic and reversible upon drug discontinuation.
*Chloroquine*
- **Chloroquine** (and hydroxychloroquine) commonly causes **corneal deposits** known as **cornea verticillata**, which appear as gray-brown, whorl-like opacities in the corneal epithelium.
- While these deposits are usually asymptomatic, high doses or prolonged use can lead to visual blurring or halos.
- The whorl pattern is a characteristic finding with this class of drugs.
Drug-Induced Pigmentary Changes Indian Medical PG Question 2: Which drug is most likely to induce photosensitivity?
- A. Metronidazole
- B. Tetracycline (Correct Answer)
- C. Ivermectin
- D. Fluconazole
Drug-Induced Pigmentary Changes Explanation: ***Tetracycline***
- **Tetracyclines** are well-known to cause **photosensitivity reactions**, leading to exaggerated sunburns, rashes, or skin discoloration upon sun exposure.
- This adverse effect is thought to be due to an interaction between the drug and UV light, leading to the formation of reactive oxygen species and subsequent cell damage.
*Metronidazole*
- While metronidazole can cause a variety of side effects, significant **photosensitivity** is generally not considered a common or prominent adverse reaction.
- It is often associated with a **disulfiram-like reaction** when consumed with alcohol, as well as gastrointestinal upset and a metallic taste.
*Ivermectin*
- **Ivermectin** is primarily used as an antiparasitic agent and is not typically associated with **photosensitivity** as a common side effect.
- Its main adverse effects are usually related to the Mazzotti reaction during treatment of onchocerciasis or other systemic symptoms like dizziness or nausea.
*Fluconazole*
- **Fluconazole**, an antifungal medication, has a relatively low incidence of causing **photosensitivity** compared to other drug classes.
- Common side effects include gastrointestinal disturbances, headache, and elevated liver enzymes, but severe phototoxic reactions are rare.
Drug-Induced Pigmentary Changes Indian Medical PG Question 3: A 17 year old girl had been taking a drug for the treatment of acne for the last 2 years, which has led to pigmentation. Which drug could it be?
- A. Doxycycline
- B. Minocycline (Correct Answer)
- C. Clindamycin
- D. Azithromycin
Drug-Induced Pigmentary Changes Explanation: ***Minocycline***
- **Minocycline** is a **tetracycline** antibiotic commonly used for acne and is notorious for causing various forms of **pigmentation**, including blue-gray discoloration of the skin, scars, and teeth, especially with long-term use.
- This pigmentation is due to the formation of **insoluble chelates** of minocycline with iron and melanin within tissues.
*Doxycycline*
- While also a **tetracycline**, **doxycycline** is less commonly associated with significant **skin pigmentation** compared to minocycline at standard acne treatment doses.
- Its side effect profile for pigmentation usually involves **photosensitivity** or **tooth discoloration** in children, not generally diffuse skin discoloration in adolescents.
*Clindamycin*
- **Clindamycin** is a **lincosamide antibiotic** primarily used topically or orally for acne, but it does not cause **pigmentation** as a known side effect.
- Its main systemic side effect concern is **Clostridioides difficile-associated diarrhea (CDAD)**.
*Azithromycin*
- **Azithromycin** is a **macrolide antibiotic** and is not typically associated with **skin pigmentation** as a side effect.
- It is sometimes used for acne, but its side effects are primarily **gastrointestinal** (nausea, vomiting, diarrhea).
Drug-Induced Pigmentary Changes Indian Medical PG Question 4: A patient with TB on DOTS develops orange-red discoloration of urine and tears. Which drug is responsible?
- A. Ethambutol
- B. Rifampicin (Correct Answer)
- C. Pyrazinamide
- D. Isoniazid
Drug-Induced Pigmentary Changes Explanation: ***Rifampicin***
- **Rifampicin** is well-known for causing **orange-red discoloration** of urine, sweat, tears, and other body fluids due to its intrinsic color.
- This side effect is benign and does not indicate liver damage or other serious toxicity, but patients should be informed about it.
*Ethambutol*
- **Ethambutol** is primarily associated with **optic neuritis**, leading to decreased visual acuity and red-green color blindness.
- It does not cause discoloration of body fluids.
*Pyrazinamide*
- **Pyrazinamide** is commonly associated with **hepatotoxicity** and **hyperuricemia**, which can lead to gout.
- It does not cause discoloration of body fluids.
*Isoniazid*
- **Isoniazid** is known to cause **peripheral neuropathy** (prevented by pyridoxine supplementation) and **hepatotoxicity**.
- It does not cause discoloration of body fluids.
Drug-Induced Pigmentary Changes Indian Medical PG Question 5: Krukenberg's spindle seen in patients with pigmentary glaucoma refers to deposition of pigment on
- A. Trabecular meshwork
- B. Anterior surface of the lens
- C. Back of cornea (Correct Answer)
- D. Posterior surface of iris
Drug-Induced Pigmentary Changes Explanation: ***Back of cornea***
- **Krukenberg's spindle** is a classic sign of **pigment dispersion syndrome** and subsequent pigmentary glaucoma.
- It results from the deposition of **pigment granules** on the **endothelium of the central posterior cornea**, forming a **vertical spindle-shaped pattern**.
- This is a pathognomonic finding that helps distinguish pigmentary glaucoma from other forms of glaucoma.
*Incorrect: Trabecular meshwork*
- While **pigment deposition** on the trabecular meshwork is crucial in pigmentary glaucoma, leading to **increased outflow resistance** and elevated intraocular pressure, the term **Krukenberg's spindle** specifically refers to pigment on the corneal endothelium.
- Pigment on the trabecular meshwork appears as **increased pigmentation of the angle** on gonioscopy, sometimes described as **Scheie's stripe** or **Sampaolesi's line**.
*Incorrect: Anterior surface of the lens*
- Pigment can deposit on the **anterior lens capsule** in pigment dispersion syndrome, appearing as fine dusting.
- However, this deposition is **not referred to as Krukenberg's spindle**, which is specific to the posterior corneal surface.
*Incorrect: Posterior surface of iris*
- In pigment dispersion syndrome, **pigment is released FROM the posterior iris** due to mechanical rubbing against zonular fibers, creating **radial transillumination defects**.
- However, Krukenberg's spindle refers to where pigment is **deposited** (corneal endothelium), not where it originates from.
Drug-Induced Pigmentary Changes Indian Medical PG Question 6: Dermatological manifestation of which of the following diseases?
- A. Photo dermatitis
- B. Pellagra (Correct Answer)
- C. Acrodermatitis enteropathica
- D. Vitamin B deficiency
Drug-Induced Pigmentary Changes Explanation: ***Pellagra***
- The image shows a classic "butterfly" rash on the face, specifically a photosensitive dermatitis, which is a hallmark of **pellagra**.
- Pellagra is caused by a deficiency of **niacin (vitamin B3)**, characterized by the "3 D's": **dermatitis**, **diarrhea**, and **dementia**.
*Photo dermatitis*
- While pellagra often presents with photosensitive dermatitis, "photo dermatitis" is a general term for **skin inflammation caused by light exposure** and not a specific disease itself.
- It could be caused by various factors, including medication, immune reactions, or other underlying conditions, but the pattern seen here is highly suggestive of pellagra.
*Acrodermatitis enteropathica*
- This condition is a **hereditary zinc deficiency** that typically presents with a periorificial and acral dermatitis.
- The skin lesions are typically **vesicular-pustular or eczematous** and do not usually have the distinct butterfly pattern of photosensitive dermatitis seen in the image.
*Vitamin B deficiency*
- While pellagra is a vitamin B **(niacin, B3)** deficiency, this option is too broad.
- Other vitamin B deficiencies, such as **riboflavin (B2)** or **pyridoxine (B6)** deficiency, have different dermatological manifestations like angular cheilitis, glossitis, or seborrheic dermatitis, but not the characteristic facial rash seen here.
Drug-Induced Pigmentary Changes Indian Medical PG Question 7: Which of the following is not true about hydroquinone?
- A. Response is incomplete and pigmentation may recur
- B. It inhibits tyrosinase
- C. It requires prescription strength concentrations above 2%
- D. It should not be used for melasma or chloasma of pregnancy (Correct Answer)
Drug-Induced Pigmentary Changes Explanation: ***It should not be used for melasma or chloasma of pregnancy***
- This statement is **NOT TRUE** - hydroquinone is actually a **first-line treatment for melasma** including chloasma (melasma of pregnancy)
- Hydroquinone 2-4% is one of the **most effective topical agents** for treating melasma and is widely recommended in dermatological guidelines
- While hydroquinone use during **active pregnancy** is approached with caution (FDA Category C), it is definitely indicated for treating melasma/chloasma **after pregnancy** and for general melasma in non-pregnant patients
- The condition (melasma/chloasma) is appropriately treated with hydroquinone; only the **timing during pregnancy** requires consideration
*Response is incomplete and pigmentation may recur*
- This is a **TRUE statement** about hydroquinone therapy
- Treatment response is often **incomplete** with partial lightening of hyperpigmentation
- **Recurrence is common** after discontinuation, especially with continued sun exposure or hormonal triggers
- Maintenance therapy is often needed to sustain results
*It inhibits tyrosinase*
- This is a **TRUE statement** - hydroquinone's primary mechanism of action
- Acts as a **competitive inhibitor of tyrosinase**, the rate-limiting enzyme in melanin synthesis
- This inhibition reduces melanin production in melanocytes, leading to depigmentation
*It requires prescription strength concentrations above 2%*
- This is a **TRUE statement** in most countries including India and the USA
- Hydroquinone concentrations **≤2%** are available over-the-counter (OTC)
- Concentrations **>2% (typically 3-4%)** require a prescription
- Higher concentrations provide greater efficacy but also increased risk of side effects like ochronosis
Drug-Induced Pigmentary Changes Indian Medical PG Question 8: Cutis marmorata occurs due to exposure to –
- A. Cold temperature (Correct Answer)
- B. Dust
- C. Hot temperature
- D. Humidity
Drug-Induced Pigmentary Changes Explanation: ***Cold temperature***
- **Cutis marmorata** is a physiological response to **cold temperatures**, characterized by a mottled, reticulated vascular pattern on the skin.
- This occurs due to **vasoconstriction** of the small arteries and arterioles, alongside **vasodilation** of the venules, creating the characteristic marbled appearance.
*Dust*
- Exposure to **dust** typically causes **irritation**, allergic reactions, or respiratory issues, such as **dermatitis**, **contact urticaria**, or **asthma**.
- It does not directly lead to the characteristic vascular changes seen in cutis marmorata.
*Hot temperature*
- **Hot temperatures** generally cause **vasodilation** in the skin to facilitate **heat dissipation**, leading to redness and warmth.
- This is the opposite physiological response to cutis marmorata, which involves vasoconstriction.
*Humidity*
- **Humidity** primarily affects **skin hydration** and the rate of perspiration, potentially exacerbating certain skin conditions like **eczema** or **fungal infections**.
- High or low humidity does not directly induce the vascular changes that result in cutis marmorata.
Drug-Induced Pigmentary Changes Indian Medical PG Question 9: What is the most common association with Acanthosis nigricans?
- A. Hypertension
- B. Diabetes Mellitus
- C. Obesity (Correct Answer)
- D. Hypothyroidism
Drug-Induced Pigmentary Changes Explanation: **Explanation:**
**Acanthosis Nigricans (AN)** is a common dermatological condition characterized by hyperpigmented, velvety plaques, typically found in intertriginous areas like the axilla and neck.
**Why Obesity is the Correct Answer:**
Obesity is the **most common** association and cause of Acanthosis Nigricans (Pseudo-acanthosis nigricans). The underlying mechanism is **Insulin Resistance**. In obese individuals, high levels of circulating insulin bind to **Insulin-like Growth Factor-1 (IGF-1) receptors** on keratinocytes and fibroblasts. This stimulates excessive proliferation of these cells, leading to the characteristic epidermal thickening and hyperpigmentation.
**Analysis of Incorrect Options:**
* **Diabetes Mellitus (B):** While AN is a strong cutaneous marker for Type 2 Diabetes, it usually precedes the clinical onset of diabetes. Obesity remains the primary driver and more frequent association.
* **Hypertension (A) & Hypothyroidism (D):** These are often part of the "Metabolic Syndrome" or associated endocrinopathies (like PCOS), but they are not the primary or most common cause of the skin changes seen in AN.
**High-Yield Clinical Pearls for NEET-PG:**
* **Malignant Acanthosis Nigricans:** If AN appears suddenly, is very extensive, or involves the palms (**Tripe Palms**) and oral mucosa, it is highly suggestive of internal malignancy, most commonly **Gastric Adenocarcinoma**.
* **Histopathology:** Shows hyperkeratosis and papillomatosis. Note that "acanthosis" (thickening of the stratum spinosum) is actually minimal despite the name.
* **Common Sites:** Neck (most common), axilla, groins, and knuckles.
* **Drug-induced AN:** Can be caused by Nicotinic acid, systemic corticosteroids, and OCPs.
Drug-Induced Pigmentary Changes Indian Medical PG Question 10: Defect seen in Vitiligo is:
- A. Absent melanosomes
- B. Absent melanocytes (Correct Answer)
- C. Reduction in melanin synthesis
- D. Reduction in number of melanocytes
Drug-Induced Pigmentary Changes Explanation: **Explanation:**
**Vitiligo** is an acquired, chronic pigmentary disorder characterized by the selective destruction of melanocytes.
**1. Why Option B is correct:**
The hallmark of vitiligo is the **complete absence of functional melanocytes** in the affected skin. This is primarily due to an autoimmune-mediated destruction where T-cells target melanocyte-specific antigens. Histopathologically, a skin biopsy of a stable vitiligo lesion shows a total lack of melanocytes (DOPA-negative) and a consequent absence of melanin in the epidermis.
**2. Why other options are incorrect:**
* **Option A (Absent melanosomes):** This is seen in **Chediak-Higashi syndrome** or specific trafficking defects. In vitiligo, the "factory" (melanocyte) is gone, so melanosomes are naturally absent, but the primary defect is the cell loss itself.
* **Option C (Reduction in melanin synthesis):** This describes **Albinism**, where melanocytes are present in normal numbers, but there is a genetic defect in the enzyme tyrosinase, leading to decreased melanin production.
* **Option D (Reduction in number of melanocytes):** This describes **Nevus Depigmentosus** or **Pityriasis Alba**, where melanocytes are present but decreased in number or activity. In vitiligo, the loss is absolute in the lesion.
**High-Yield Clinical Pearls for NEET-PG:**
* **Most common association:** Autoimmune thyroid disease (Hashimoto’s).
* **Koebner Phenomenon:** Vitiligo is Koebner positive (new lesions at sites of trauma).
* **Segmental Vitiligo:** Does not follow the Koebner phenomenon and has a dermatomal distribution.
* **Treatment of Choice:** Narrowband UVB (NB-UVB) is the gold standard for generalized vitiligo.
* **Wood’s Lamp:** Lesions show a characteristic **"milky white"** fluorescence.
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