Post-inflammatory Hyperpigmentation Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Post-inflammatory Hyperpigmentation. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Post-inflammatory Hyperpigmentation Indian Medical PG Question 1: Mycosis fungoides primarily involves which type of immune cell?
- A. NK cells
- B. B lymphocytes
- C. Plasma cells
- D. T lymphocytes (Correct Answer)
Post-inflammatory Hyperpigmentation Explanation: ***CD4+ T Cells***
- Mycosis fungoides is a type of **cutaneous T-cell lymphoma**, primarily involving **CD4+ T cells** which infiltrate the skin [1][2].
- The disease is characterized by **pleomorphic** skin lesions caused by **malignant T-cell proliferation** [3].
*K Cells (not primarily involved in mycosis fungoides)*
- K Cells are involved in **immunological responses** but are not specifically linked to mycosis fungoides.
- They do not play a primary role in **cutaneous lymphoproliferative disorders**.
*B Cells (involved in humoral immunity)*
- B Cells are mainly responsible for **antibody production**, which is not the primary mechanism in mycosis fungoides.
- The condition involves **T cell malignancy**, rather than abnormalities in B cell function.
*NK Cells (part of innate immunity)*
- NK Cells are important for **innate immunity** and target viral and tumor cells but are not primarily involved in this lymphoma.
- Mycosis fungoides is characterized by **T cell-mediated responses**, not NK cell activity.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 613-614.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, p. 1162.
[3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 564-565.
Post-inflammatory Hyperpigmentation Indian Medical PG Question 2: False about Tinea versicolor
- A. Lesions can be both hypo & hyperpigmented
- B. It is superficial fungal infection caused by Malassezia
- C. Scratch sign is positive
- D. Wood's lamp examination gives Apple green Fluorescence (Correct Answer)
Post-inflammatory Hyperpigmentation Explanation: ***Wood's lamp examination gives Apple green Fluorescence***
- **Tinea versicolor** typically exhibits a **yellow-green or yellowish-orange fluorescence** under Wood's lamp, not an apple-green fluorescence.
- **Apple-green fluorescence** is characteristic of certain bacterial infections, such as those caused by *Pseudomonas aeruginosa*, but not for *Malassezia* species in Tinea versicolor.
*Lesions can be both hypo & hyperpigmented*
- This statement is true; **Tinea versicolor** lesions can indeed present as **hypopigmented (lighter)** or **hyperpigmented (darker)** patches.
- The color variation is due to *Malassezia's* interference with melanin production or its direct pigment production.
*It is superficial fungal infection caused by Malassezia*
- This statement is true; **Tinea versicolor** is a **superficial fungal infection** of the skin caused by species of the yeast **Malassezia**.
- The most common causative agent is **Malassezia globosa**, which is a normal commensal of the skin but can become pathogenic under certain conditions.
*Scratch sign is positive*
- This statement is true; the **scratch sign** (also known as the Besnier's sign) is positive in **Tinea versicolor**.
- When the lesions are gently scraped, fine, **powdery scales** become more apparent, which is a characteristic finding.
Post-inflammatory Hyperpigmentation Indian Medical PG Question 3: Recalcitrant acne is treated by:
- A. Steroids
- B. Retinoids (Correct Answer)
- C. Oral erythromycin
- D. Oral tetracycline
Post-inflammatory Hyperpigmentation Explanation: ***Retinoids***
- **Oral retinoids**, particularly **isotretinoin**, are highly effective for **recalcitrant, severe acne** that has not responded to conventional therapies.
- They work by reducing **sebum production**, inhibiting **Propionibacterium acnes**, normalizing **follicular keratinization**, and possessing **anti-inflammatory** properties.
*Steroids*
- **Systemic steroids** are generally not used for long-term acne treatment due to significant side effects and the potential for **steroid-induced acne**.
- They may be used short-term for **severe nodulocystic acne** with significant inflammation, but not as a primary treatment for recalcitrance.
*Oral erythromycin*
- **Oral erythromycin** is an antibiotic sometimes used for acne, but resistance is common, limiting its effectiveness, especially in **recalcitrant cases**.
- It primarily targets **Propionibacterium acnes** and has some **anti-inflammatory** effects, but is less potent than retinoids for severe, persistent acne.
*Oral tetracycline*
- **Oral tetracyclines** (e.g., doxycycline, minocycline) are commonly used for moderate to severe acne, but if acne is **recalcitrant**, it indicates a lack of response to these antibiotics.
- Their mechanism involves reducing **bacterial growth** and inflammation, but they do not address the underlying pathogenesis of severe acne as comprehensively as retinoids.
Post-inflammatory Hyperpigmentation Indian Medical PG Question 4: A 35 years old female presented with acne. She was treated for her acne but after the treatment, she developed pigmentation. Which drug is responsible for hyperpigmentation?
- A. Minocycline (Correct Answer)
- B. Doxycycline
- C. Tetracycline
- D. Erythromycin
Post-inflammatory Hyperpigmentation Explanation: ***Minocycline***
- **Minocycline** is known to cause different types of hyperpigmentation, including blue-grey discoloration of the skin, scars, mucosa, eyes, and teeth, especially with long-term use.
- This pigmentation can be due to the accumulation of **iron oxide** and **minocycline degradation products** in tissues.
*Doxycycline (a tetracycline antibiotic)*
- While doxycycline is a tetracycline, it is **less commonly associated with significant hyperpigmentation** compared to minocycline.
- It can cause photosensitivity, which might lead to hyperpigmentation in sun-exposed areas, but direct drug-induced blue-grey discoloration is rare.
*Tetracycline (a tetracycline antibiotic)*
- **Tetracycline** can cause tooth discoloration, especially in children, and photosensitivity, but direct drug-induced skin hyperpigmentation as described is **less common** than with minocycline.
- Other side effects like gastrointestinal upset are more prominent.
*Erythromycin (a macrolide antibiotic)*
- **Erythromycin** is a macrolide antibiotic and is **not typically associated with significant skin hyperpigmentation** as a side effect.
- Common side effects include gastrointestinal disturbances like nausea, vomiting, and diarrhea.
Post-inflammatory Hyperpigmentation Indian Medical PG Question 5: Dermatological manifestation of which of the following diseases?
- A. Photo dermatitis
- B. Pellagra (Correct Answer)
- C. Acrodermatitis enteropathica
- D. Vitamin B deficiency
Post-inflammatory Hyperpigmentation 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.
Post-inflammatory Hyperpigmentation Indian Medical PG Question 6: 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)
Post-inflammatory Hyperpigmentation 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
Post-inflammatory Hyperpigmentation Indian Medical PG Question 7: In a patient with the following lesion on scalp, what changes are seen in the nails?
- A. Azure nails
- B. Dorsal pterygium of nails
- C. Pitting of nails (Correct Answer)
- D. Yellow nail discolouration
Post-inflammatory Hyperpigmentation Explanation: ***Pitting of nails***
- The image shows a patch of **alopecia areata** on the scalp. **Nail pitting** is the most common and characteristic nail change associated with alopecia areata, occurring in **10-66% of cases**.
- Pitting appears as small depressions or **"ice-pick" marks** on the nail surface, resulting from defective nail matrix keratinization.
- Other nail changes in alopecia areata include **trachyonychia (rough nails), red spotted lunulae, onycholysis**, and **Beau's lines**.
*Dorsal pterygium of nails*
- **Dorsal pterygium** occurs when the proximal nail fold fuses with and extends over the nail plate, creating a wing-like scar.
- This is classically associated with **lichen planus, trauma, burns, vasculitis**, and **graft-versus-host disease** — **NOT alopecia areata**.
- It can lead to permanent nail dystrophy or nail loss.
*Azure nails*
- **Azure nails** (blue nails) are typically associated with **Wilson's disease** (copper accumulation) or **minocycline use**, not alopecia areata.
- They represent a blue-gray discoloration of the nail bed or lunula.
*Yellow nail discolouration*
- **Yellow nail syndrome** is a rare condition characterized by slow-growing, thickened, yellow nails, often associated with **lymphedema** and **respiratory problems** (pleural effusions, chronic bronchitis).
- It is not linked to alopecia areata.
Post-inflammatory Hyperpigmentation Indian Medical PG Question 8: In which of the following conditions is the Koebner phenomenon most commonly observed?
- A. Psoriasis (Correct Answer)
- B. Lichen planus
- C. All of the options
- D. Viral warts
Post-inflammatory Hyperpigmentation Explanation: ***Correct: Psoriasis***
- **Psoriasis** is the **most classic and commonly cited example** of the Koebner phenomenon (isomorphic response)
- New psoriatic plaques characteristically develop at sites of cutaneous trauma, scratches, or surgical incisions in 25-50% of psoriasis patients
- This is a **pathognomonic feature** frequently tested in competitive exams and considered the prototype condition for demonstrating this phenomenon
- The mechanism involves inflammatory cascades triggered by trauma in genetically predisposed skin
*Incorrect: Lichen planus*
- While lichen planus does exhibit the Koebner phenomenon with purplish polygonal papules appearing along scratch lines, it is **less commonly observed** compared to psoriasis
- Seen in approximately 10-25% of lichen planus cases
- Not considered the primary example when teaching about Koebner phenomenon
*Incorrect: Viral warts*
- Viral warts can demonstrate **pseudo-Koebner phenomenon** where new warts form along trauma lines due to viral inoculation
- This is more accurately described as **autoinoculation** rather than true isomorphic response
- Less commonly discussed in the context of classic Koebner phenomenon compared to psoriasis
*Incorrect: All of the options*
- While all three conditions can show Koebner-like responses, the question asks for "**most commonly observed**"
- Psoriasis remains the **gold standard** and most frequently encountered example in clinical practice and medical literature
Post-inflammatory Hyperpigmentation 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
Post-inflammatory Hyperpigmentation 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.
Post-inflammatory Hyperpigmentation 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
Post-inflammatory Hyperpigmentation 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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