Treatment of Pigmentary Disorders — MCQs
Chemical peeling is indicated in all of the following except
Which drug is generally contraindicated in the management of traumatic hyphema in a patient with sickle cell disease?
Large unilateral hypopigmented lesions on the right trunk and arm in a female are best explained by which of the following?
Which type of laser is preferred for creating an iridotomy?
A 24-year-old male presents with a lesion at the site shown in the image for 4 years. He says it has increased in thickness over the years. Diagnosis is:
Which drug is used in treatment of vertigo?
A patient presents with the skin finding shown in the image. Identify the most likely diagnosis for this lesion.
Which of the following is not true about hydroquinone?
Dermatological manifestation of which of the following diseases?
A cosmetic dermatologist plans to introduce microneedling radiofrequency for acne scars. Which parameter combination would provide optimal collagen remodeling with minimal risk of thermal injury in Fitzpatrick type IV skin?
Treatment of Pigmentary Disorders Indian Medical PG Practice Questions and MCQs
Question 1: Chemical peeling is indicated in all of the following except
- A. Melasma
- B. Acne vulgaris
- C. Photoaging
- D. Lichen planus (Correct Answer)
Explanation: ***Lichen planus*** - Chemical peels are generally **contraindicated** in active inflammatory conditions like **lichen planus**, as they can worsen the inflammation or trigger a Koebner phenomenon. - While chemical peels can address post-inflammatory hyperpigmentation, they should not be used during the active phase of lichen planus due to the risk of exacerbation. *Melasma* - **Melasma** is a common indication for chemical peels, particularly superficial and medium-depth peels, to reduce hyperpigmentation. - Peels containing agents like **glycolic acid**, salicylic acid, or trichloroacetic acid are often used to lighten melanin deposits. *Acne vulgaris* - Chemical peels are effective in treating **acne vulgaris** by exfoliating the skin, reducing comedones, and improving overall skin texture. - **Salicylic acid peels** are particularly useful due to their lipophilic nature, allowing them to penetrate and clean pores. *Photoaging* - **Photoaging**, characterized by fine lines, wrinkles, and dyspigmentation from sun exposure, is a primary indication for chemical peels. - Peels can promote **collagen remodeling** and help achieve a more even skin tone and smoother texture.
Question 2: Which drug is generally contraindicated in the management of traumatic hyphema in a patient with sickle cell disease?
- A. Timolol
- B. Steroids
- C. Acetazolamide (Correct Answer)
- D. Atropine
Explanation: ***Acetazolamide*** - **Acetazolamide** is a **carbonic anhydrase inhibitor** that is **generally contraindicated** in patients with **sickle cell disease or trait**. - It causes **systemic acidosis** by increasing renal bicarbonate excretion, which lowers blood pH. - **Acidosis promotes sickling** of red blood cells, which can lead to **vaso-occlusion**, increased blood viscosity, and potential complications including **anterior chamber obstruction** and **secondary glaucoma**. - Despite its usefulness in lowering intraocular pressure in other settings, this risk makes it contraindicated in sickle cell patients with hyphema. *Timolol* - **Timolol** is a **beta-blocker** that reduces aqueous humor production and is generally **safe and effective** for reducing **intraocular pressure** in traumatic hyphema. - It does not cause systemic acidosis or affect red blood cell sickling. - Commonly used in hyphema management regardless of sickle cell status. *Steroids* - **Topical or systemic steroids** are often used to reduce **inflammation** and anterior chamber reaction in traumatic hyphema. - They help prevent **secondary hemorrhage** and reduce complications. - They do not contribute to red blood cell sickling or systemic acidosis and are safe in sickle cell disease. *Atropine* - **Atropine** is a **cycloplegic agent** used to paralyze the ciliary body and dilate the pupil, which helps **relieve pain** and prevent **posterior synechiae** in hyphema. - It has no adverse effects related to **sickle cell disease** or red blood cell sickling. - Routinely used in hyphema management.
Question 3: 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
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.
Question 4: Which type of laser is preferred for creating an iridotomy?
- A. Nd:YAG laser (Correct Answer)
- B. CO2 laser
- C. Argon laser
- D. Diode laser
Explanation: ***Nd:YAG laser*** - The **Nd:YAG laser** is the preferred laser for creating an iridotomy, particularly for **laser peripheral iridotomy (LPI)** in angle-closure glaucoma management. - It works by **photodisruption**, which generates plasma and acoustic shockwaves that effectively fracture iris tissue, creating a precise opening without significant thermal damage. - The Nd:YAG laser has largely replaced the Argon laser as the first-line choice due to fewer complications, less inflammation, and reduced risk of iridotomy closure. *Argon laser* - The **Argon laser** was historically used for iridotomy and can still be effective, but it primarily works by **photocoagulation**, causing thermal damage through light absorption by pigmented tissues. - It is associated with **more inflammatory response**, requires multiple applications, and has higher rates of iridotomy closure over time due to scarring from thermal effects. - Currently used as an alternative or adjunct to Nd:YAG, particularly in eyes with lighter iris pigmentation. *CO2 laser* - The **CO2 laser** operates in the far-infrared spectrum and is highly absorbed by water, making it suitable for general tissue ablation but not appropriate for intraocular procedures. - Its large spot size and significant thermal spread make it unsuitable for creating a small, precise iridotomy in the delicate iris tissue. - Not used in routine ophthalmic surgery for iridotomy. *Diode laser* - **Diode lasers** are widely used in ophthalmology for retinal photocoagulation, cyclophotocoagulation for glaucoma, and transpupillary thermotherapy, due to excellent absorption by melanin and hemoglobin. - For creating an iridotomy, they are not as precise or effective as the Nd:YAG laser and cause more thermal collateral damage to surrounding iris tissue. - Their primary utility is in thermal applications, not photodisruptive procedures like iridotomy.
Question 5: A 24-year-old male presents with a lesion at the site shown in the image for 4 years. He says it has increased in thickness over the years. Diagnosis is:
- A. Spitz nevus
- B. Hyper-melanosis of Ito
- C. Becker's nevus (Correct Answer)
- D. Congenital melanocytic nevus
Explanation: ***Becker's nevus*** - This lesion typically presents as a **unilateral, hyperpigmented patch** that often appears during childhood or adolescence, increasing in size and thickness with associated **hypertrichosis** (increased hair growth). The image shows a large, irregularly shaped, hyperpigmented area on the torso of a young male, consistent with this description. - The history of increasing thickness over four years further supports **Becker's nevus**, as it is known to progress in thickness and texture, often becoming more indurated and sometimes verrucous. *Spitz nevus* - Spitz nevus is a benign melanocytic nevus typically presenting as a **pink or red, dome-shaped papule or nodule**, commonly on the face or limbs. - It rapidly grows but does not typically present as a large, hyperpigmented patch with associated hypertrichosis like the lesion shown. *Hyper-melanosis of Ito* - Hypermelanosis of Ito (also known as incontinentia pigmenti achromians) is characterized by **streaky or whorled hypopigmented (lighter) skin lesions**, often present at birth or in early infancy. - The image clearly shows a **hyperpigmented (darker) lesion**, which directly contradicts the characteristic hypopigmentation of hypermelanosis of Ito. *Congenital melanocytic nevus* - Congenital melanocytic nevi are typically present **at birth** or become apparent shortly thereafter. While they can be large and hyperpigmented, they usually do not have the prominent feature of increasing thickness and hypertrichosis developing many years later in adolescence or early adulthood in the same way as Becker's nevus. - The description of a lesion appearing during adolescence and increasing in thickness and hairiness for four years makes Becker's nevus a more specific diagnosis than a general congenital melanocytic nevus.
Question 6: Which drug is used in treatment of vertigo?
- A. Metoclopramide
- B. Cisapride
- C. Cinnarizine (Correct Answer)
- D. None of the options
Explanation: ***Cinnarizine***- **Cinnarizine** is an antihistamine and calcium channel blocker known for its anti-vertigo and anti-emetic properties [2].- It works by suppressing the **vestibular system** and reducing the excitability of sensory hair cells in the inner ear [1].*Metoclopramide*- **Metoclopramide** is a **dopamine receptor antagonist** primarily used as an anti-emetic and for treating gastroparesis.- While it can alleviate nausea and vomiting associated with vertigo, it does not directly treat the underlying sensation of **vertigo** itself by acting on the vestibular system.*Cisapride*- **Cisapride** is a **serotonin 5-HT4 receptor agonist** that acts as a gastroprokinetic agent, enhancing gastrointestinal motility [3].- It is not used for vertigo and has been associated with serious **cardiac arrhythmias**, leading to restricted use in many countries [3].*None of the options*- This option is incorrect because **Cinnarizine** is a well-established medication used in the treatment of vertigo [2].- Other options are not primarily indicated for vertigo treatment.
Question 7: 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
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.
Question 8: 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)
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
Question 9: Dermatological manifestation of which of the following diseases?
- A. Photo dermatitis
- B. Pellagra (Correct Answer)
- C. Acrodermatitis enteropathica
- D. Vitamin B deficiency
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.
Question 10: A cosmetic dermatologist plans to introduce microneedling radiofrequency for acne scars. Which parameter combination would provide optimal collagen remodeling with minimal risk of thermal injury in Fitzpatrick type IV skin?
- A. Needle depth 3.5 mm, temperature 70°C, pulse duration 1000 ms
- B. Needle depth 4 mm, temperature 75°C, pulse duration 500 ms
- C. Needle depth 1.5-2 mm, temperature 60-65°C, pulse duration 100-200 ms (Correct Answer)
- D. Needle depth 0.5 mm, temperature 55°C, pulse duration 50 ms
Explanation: ***Needle depth 1.5-2 mm, temperature 60-65°C, pulse duration 100-200 ms*** - Optimal **collagen remodeling** occurs when the tissue is heated to **60-65°C**, which triggers the denaturation of proteins and the subsequent production of new collagen and elastin. - A depth of **1.5-2 mm** specifically targets the **papillary and mid-reticular dermis**, while the shorter pulse duration minimizes **Post-Inflammatory Hyperpigmentation (PIH)** in **Fitzpatrick type IV** skin. *Needle depth 3.5 mm, temperature 70°C, pulse duration 1000 ms* - Temperatures reaching **70°C** and very high pulse durations significantly increase the risk of **thermal necrosis** and bulk heating injuries. - A depth of **3.5 mm** is often too deep for standard facial acne scarring and may damage underlying **subcutaneous structures** or cause permanent scarring. *Needle depth 4 mm, temperature 75°C, pulse duration 500 ms* - High temperatures of **75°C** cause excessive tissue coagulation, which can lead to localized **skin burns** and prolonged downtime. - Excessive needle depth combined with high energy delivery poses a severe risk for **atrophic scarring** and pigmentary changes in darker skin types. *Needle depth 0.5 mm, temperature 55°C, pulse duration 50 ms* - A depth of **0.5 mm** is generally insufficient to reach the collagen-rich dermis required for significant improvement of **depressed acne scars**. - A temperature of **55°C** is below the threshold for effective **collagen denaturation**, resulting in suboptimal clinical outcomes for scar revision.
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