Vitiligo Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Vitiligo. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Vitiligo Indian Medical PG Question 1: Match the following woods lamp findings: 1. Erythrasma, 2. Pityriasis versicolor, 3. Tinea capitis, 4. Vitiligo || a. Yellow b. Coral red fluorescence c. Pink d. Green e. Milky white
- A. 1-d, 2-a, 3-c, 4-e
- B. 1-b, 2-a, 3-d, 4-e (Correct Answer)
- C. 1-a, 2-c, 3-e, 4-d
- D. 1-b, 2-d, 3-a, 4-c
Vitiligo Explanation: ***1-b, 2-a, 3-d, 4-e***
- **Erythrasma** is caused by *Corynebacterium minutissimum* and produces **porphyrins** that fluoresce **coral red** under a Wood's lamp [1].
- **Pityriasis versicolor** is caused by *Malassezia furfur* and typically fluoresces **yellow to yellowish-green** [2].
- **Tinea capitis** (especially due to *Microsporum* species) shows **green fluorescence** of infected hairs.
- **Vitiligo** lesions, due to a complete absence of melanin, appear as **milky white** or bright white areas under a Wood's lamp [3].
*1-d, 2-a, 3-c, 4-e*
- This option incorrectly states that Erythrasma fluoresces green. Green fluorescence is characteristic of *Microsporum* species causing **Tinea capitis**.
- Additionally, Tinea capitis is incorrectly associated with pink fluorescence, which is not a typical finding.
*1-a, 2-c, 3-e, 4-d*
- This option incorrectly states that Erythrasma fluoresces yellow. Yellow fluorescence is associated with **Pityriasis versicolor** [2].
- It also incorrectly assigns milky white fluorescence to Tinea capitis and green fluorescence to Vitiligo.
*1-b, 2-d, 3-a, 4-c*
- This option incorrectly associates Pityriasis versicolor with green fluorescence. While some variations exist, **yellow** is the more characteristic finding [2].
- It also incorrectly links Tinea capitis to yellow fluorescence and Vitiligo to pink, which are not typical Wood's lamp findings for these conditions.
Vitiligo Indian Medical PG Question 2: A child comes with a circular 3cm x 3cm scaly patchy hair loss with itching in the lesions. The investigation of choice is
- A. Tzanck smear
- B. Gram stain
- C. KOH mount (Correct Answer)
- D. Split skin smear
Vitiligo Explanation: ***Correct: KOH mount (Potassium Hydroxide mount)***
- A **KOH mount** is the investigation of choice for suspected **dermatophyte infections** (tinea capitis), which commonly present as circular, scaly patches of hair loss with itching in children.
- It involves dissolving keratinous material to visualize **fungal hyphae** and spores directly under a microscope.
- This is a quick, cost-effective, and highly specific first-line diagnostic test.
*Incorrect: Tzanck smear*
- A **Tzanck smear** is primarily used to diagnose **viral infections** like herpes simplex or varicella-zoster by identifying multinucleated giant cells.
- It is not effective for detecting fungal elements responsible for scaly hair loss.
*Incorrect: Gram stain*
- A **Gram stain** is a technique used to classify **bacteria** based on their cell wall properties.
- It would not reveal fungal hyphae or spores relevant to the described condition.
*Incorrect: Split skin smear*
- A **split skin smear** (or slit-skin smear) is typically used in the diagnosis of **leprosy** to identify acid-fast bacilli.
- This technique involves scraping the dermis and is not suitable for diagnosing superficial fungal infections.
Vitiligo Indian Medical PG Question 3: PUVA therapy is used in all except:
- A. Psoriasis
- B. Vitiligo
- C. Mycosis fungoides
- D. Melasma (Correct Answer)
Vitiligo Explanation: ***Melasma***
- **PUVA (Psoralen plus UVA) therapy** is contraindicated in melasma due to its potential to worsen hyperpigmentation and cause paradoxical darkening.
- Melasma is best managed with topical agents like **hydroquinone**, **tretinoin**, and chemical peels, along with strict **sun protection**.
*Psoriasis*
- **PUVA therapy** is a well-established and effective treatment for moderate to severe psoriasis, especially for patients with widespread plaques.
- It works by inhibiting DNA synthesis and cell proliferation in rapidly dividing keratinocytes, leading to a reduction in psoriatic lesions.
*Vitiligo*
- **PUVA therapy** is a common treatment for vitiligo, stimulating melanocyte activity and promoting repigmentation in affected areas.
- Psoralen sensitizes melanocytes to UVA light, which then encourages melanin production.
*Mycosis fungoides*
- In its early stages, **mycosis fungoides**, a cutaneous T-cell lymphoma, can be effectively treated with **PUVA therapy**.
- PUVA induces apoptosis of malignant T-cells in the skin, leading to remission of skin lesions.
Vitiligo Indian Medical PG Question 4: Large unilateral hypopigmented lesions on the right trunk and arm in a female are best explained by which of the following?
- A. Autoimmune theory
- B. Neurogenic theory (Correct Answer)
- C. Genetic predisposition
- D. Lerner's self-destruct theory
Vitiligo Explanation: ***Neurogenic theory***
- This theory posits that **neural mechanisms** play a role in the development of some hypopigmented disorders. The **unilateral distribution** along a dermatome or nerve pathway strongly supports a neurogenic origin.
- The **large, unilateral hypopigmented lesions on the right trunk and arm** are characteristic of conditions like **segmental vitiligo** or **hypopigmentation following nerve injury**, where neural factors are implicated in melanocyte dysfunction.
*Autoimmune theory*
- The autoimmune theory explains **generalized vitiligo**, where the body's immune system attacks melanocytes, leading to widespread depigmentation.
- It does not account for the **segmental, unilateral distribution** observed in this case, which is typically not seen in autoimmune conditions.
*Genetic predisposition*
- While genetics can increase susceptibility to certain pigmentary disorders, it does not explain the **unilateral, segmental pattern** of hypopigmentation.
- Genetic factors usually lead to more generalized or bilateral presentations rather than a localized, nerve-distribution pattern.
*Lerner's self-destruct theory*
- **Lerner's self-destruct theory** suggests that melanocytes may destroy themselves from within due to metabolic defects or oxidative stress.
- This theory also fails to explain the **unilateral, dermatomal distribution** of the lesions, as self-destruction would likely occur more randomly or symmetrically.
Vitiligo Indian Medical PG Question 5: Koebner's phenomenon is seen in all except
- A. Psoriasis
- B. Warts
- C. Tinea corporis (Correct Answer)
- D. Molluscum contagiosum
Vitiligo Explanation: ***Tinea corporis***
- **Koebner's phenomenon**, also known as the isomorphic response, is the appearance of skin lesions characteristic of a **pre-existing dermatosis** at sites of **trauma** to previously uninvolved skin.
- **Tinea corporis**, a **superficial fungal infection**, does NOT exhibit true Koebner's phenomenon.
- Its spread occurs through **direct fungal contact or autoinoculation**, not through an isomorphic response to non-specific trauma.
*Psoriasis*
- **Psoriasis** is the **classic example** of Koebner's phenomenon.
- New psoriatic plaques can appear at sites of **skin trauma** such as scratches, surgical scars, burns, or tattoos within **10-20 days** of injury.
- This occurs in approximately **25-50%** of psoriasis patients.
*Warts*
- **Warts** (verruca vulgaris), caused by **human papillomavirus (HPV)**, can show what is sometimes called **pseudo-Koebner's phenomenon**.
- Trauma facilitates **viral inoculation** and seeding of HPV into the skin, leading to new wart formation along scratch lines.
- However, this is technically **viral spread through trauma**, not a true isomorphic response of a pre-existing dermatosis.
*Molluscum contagiosum*
- **Molluscum contagiosum** can similarly demonstrate **pseudo-Koebner's phenomenon**.
- Scratching spreads the **molluscum contagiosum virus** to adjacent areas, creating linear arrays of lesions.
- Like warts, this represents **direct viral inoculation** rather than true isomorphic response, but is often grouped with Koebner's phenomenon in clinical practice.
Vitiligo Indian Medical PG Question 6: Koebner's phenomenon seen in ?
- A. Lichen nitidus
- B. Psoriasis
- C. All of the options (Correct Answer)
- D. Vitiligo
Vitiligo Explanation: ***All of the options***
- **Koebner's phenomenon** (isomorphic response) refers to the development of new lesions at sites of **skin trauma** in patients with pre-existing dermatological conditions.
- **All four conditions listed** can exhibit Koebner's phenomenon, making this the correct answer.
**Psoriasis**
- The **most classic and frequently cited** example of Koebner's phenomenon.
- Physical injury triggers characteristic red, scaly plaques at trauma sites.
- Seen in approximately **25-50%** of psoriasis patients.
**Vitiligo**
- Well-documented to exhibit **Koebner's phenomenon**.
- New **depigmented patches** appear at sites of trauma, cuts, or friction.
- Important diagnostic and prognostic indicator in vitiligo patients.
**Lichen planus**
- Classic condition showing **Koebner's phenomenon**.
- New violaceous, flat-topped papules develop at trauma sites.
- One of the hallmark features of this condition.
**Lichen nitidus**
- Although less commonly emphasized, **Lichen nitidus can exhibit Koebner's phenomenon**.
- Tiny, shiny papules may appear in linear distribution following trauma.
- Part of the lichenoid reaction group that shows isomorphic response.
Vitiligo Indian Medical PG Question 7: "Isomorphic response" can be a feature of the following except
- A. Tinea (Correct Answer)
- B. Warts
- C. Molluscum contagiosum
- D. Psoriasis
Vitiligo Explanation: ***Tinea***
- The **isomorphic response (Koebner phenomenon)** refers to the development of new skin lesions in areas of trauma due to an immunological process.
- This phenomenon is **not typically seen in tinea** (fungal infections).
- While tinea can spread to new areas, this occurs through **direct fungal inoculation and contact spread**, not through the true Koebner mechanism.
*Warts*
- **Warts** caused by human papillomavirus (HPV) can exhibit the **isomorphic response**.
- Trauma to the skin can lead to **viral inoculation** in that area, resulting in new wart formation along lines of trauma.
- This is a well-recognized example of Koebner phenomenon in viral infections.
*Molluscum contagiosum*
- **Molluscum contagiosum** (poxvirus infection) can demonstrate the **isomorphic response**.
- **Scratching or rubbing** can spread the virus to new areas through autoinoculation.
- New lesions develop along the lines of trauma, consistent with Koebner phenomenon.
*Psoriasis*
- **Psoriasis** is the **classic and most well-known** condition exhibiting the isomorphic response or Koebner phenomenon.
- New psoriatic plaques appear in areas of **skin injury** (scratches, cuts, burns, surgical incisions, friction).
- Seen in approximately **25-50%** of psoriasis patients.
Vitiligo Indian Medical PG Question 8: A patient presents with the skin finding shown in the image. Identify the most likely diagnosis for this lesion.
- A. Vitiligo
- B. Contact leukoderma
- C. Piebaldism (Correct Answer)
- D. Albinism
Vitiligo Explanation: ***Piebaldism***
- The image shows a **localized patch of depigmentation** on the forehead, characteristic of **piebaldism**.
- **Piebaldism** is a rare, congenital autosomal dominant disorder caused by a defect in melanocyte development and migration, resulting in stable, well-demarcated depigmented areas, often with a **white forelock**.
*Vitiligo*
- **Vitiligo** typically presents as **progressive, acquired macules and patches of depigmentation** that often enlarge over time.
- While it can appear on the face, the sharply demarcated, congenital appearance seen here is more consistent with piebaldism.
*Contact leukoderma*
- **Contact leukoderma** is an **acquired depigmentation** resulting from exposure to chemicals (e.g., rubber, phenols).
- It would usually present in areas of direct contact, and the congenital nature of the lesion in the image rules this out.
*Albinism*
- **Albinism** is a **generalized hypopigmentation** affecting the skin, hair, and eyes due to a defect in melanin production.
- The image shows a localized patch of depigmentation, not a widespread lack of pigment characteristic of albinism.
Vitiligo Indian Medical PG Question 9: A young girl presents with leukotrichia and lesions as shown in the image. What is the most likely diagnosis?
- A. Segmental vitiligo (Correct Answer)
- B. Piebaldism
- C. Focal vitiligo
- D. Nevus depigmentosus
Vitiligo Explanation: ***Segmental vitiligo***
- Segmental vitiligo characteristically presents as unilateral, **dermatomal** or **quasi-dermatomal depigmentation** with sharply demarcated borders, often including overlying **leukotrichia** (white hairs) in the affected area, as seen in the image.
- This form typically has an early onset, rapid progression followed by stabilization, and can be more resistant to conventional treatments than non-segmental vitiligo.
*Piebaldism*
- Piebaldism is a **congenital leukoderma** characterized by a **white forelock** and symmetrically distributed depigmented patches, primarily on the trunk and extremities, which are usually stable in size and present from birth.
- Unlike the progressive nature and unilateral pattern seen in the image, piebaldism is a genetic condition without new lesion development or the characteristic dermatomal distribution.
*Focal vitiligo*
- Focal vitiligo refers to one or a few localized depigmented macules that do not have a segmental pattern and are not distributed along a specific dermatome.
- While it involves localized depigmentation, the clear **segmental distribution** and presence of **leukotrichia** in the image are more indicative of segmental vitiligo.
*Nevus depigmentosus*
- Nevus depigmentosus is a congenital, **stable hypopigmented lesion** that typically appears as a solitary patch or macule, without subsequent growth or change in size over time.
- The lesions shown in the image appear to be multiple and follow a distinct pattern that is not typical of a stable, solitary nevus.
Vitiligo Indian Medical PG Question 10: A 35-year-old obese woman presents with recurrent lesions in both axilla in summer season. Wood lamp examination is shown. The diagnosis is:
- A. Ecthyma
- B. Erythrasma (Correct Answer)
- C. Impetigo contagiosa
- D. Bullous impetigo
Vitiligo Explanation: ***Erythrasma***
- Erythrasma is a superficial bacterial infection caused by **Corynebacterium minutissimum**, which commonly presents as red-brown patches in intertriginous areas like the axilla, especially in obese individuals and warm, humid conditions (summer season).
- The distinctive **coral-red fluorescence under Wood's lamp** is due to porphyrin production by the bacteria, which is a classic diagnostic feature of erythrasma, as shown in the image.
*Ecthyma*
- Ecthyma is a deeper form of impetigo characterized by **ulcerative lesions with a thick, adherent crust** that extend into the dermis.
- It is typically caused by *Streptococcus pyogenes* and sometimes *Staphylococcus aureus*, and would not exhibit coral-red fluorescence under Wood's lamp.
*Impetigo contagiosa*
- Impetigo contagiosa (non-bullous impetigo) presents with **honey-colored crusted lesions**, usually on the face and extremities.
- While also a bacterial skin infection, it is typically caused by *Staphylococcus aureus* or *Streptococcus pyogenes* and does not show coral-red fluorescence under Wood's lamp.
*Bullous impetigo*
- Bullous impetigo is characterized by **flaccid bullae** (blisters) that rupture to form thin, varnish-like crusts, primarily caused by *Staphylococcus aureus* producing exfoliative toxins.
- Similar to other forms of impetigo, it does not produce the coral-red fluorescence under Wood's lamp.
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