PUVA Therapy — MCQs
Which statement about systemic steroids in psoriasis is correct:
In which of the following conditions is phototherapy, specifically ultraviolet light therapy, useful for treatment?
PUVA therapy is used in all except:
In which of the following conditions does IOL implantation after cataract surgery require the greatest caution and specialized management?
Dose of vitamin A for an 18 month old baby, with keratomalacia, weighing 10 kg is?
The most common mechanism of resistance to drugs in Staphylococcus is
All of the following are adverse effects of nicotinic acid except:
Vitamin D analogues (such as calcitriol and calcipotriol) are useful in the treatment of:
Which of the following is NOT a complication of PUVA therapy?
A 12-year-old boy, after spending his holiday on a beach, develops pruritic hemorrhagic vesicles on his cheeks, ears, nose, and hands 12 hours after sun exposure. A week later, the lesions crusted and healed with permanent scars. What is the most probable diagnosis?
PUVA Therapy Indian Medical PG Practice Questions and MCQs
Question 1: Which statement about systemic steroids in psoriasis is correct:
- A. No definitive indication exists (Correct Answer)
- B. Only as bridge therapy in rare cases
- C. Emergency situations under specialist supervision only
- D. Systemic steroids are contraindicated in all forms of psoriasis
Explanation: ***No definitive indication exists*** - Systemic steroids have **no established therapeutic role** in psoriasis management and are **strongly avoided** in clinical practice. - They can cause severe **rebound flares** upon withdrawal and may precipitate life-threatening **pustular psoriasis** or **erythrodermic psoriasis**. - While not absolutely contraindicated in every conceivable scenario, they provide **no long-term benefit** and actively worsen disease control by masking symptoms and creating dependency. - This statement most accurately reflects the medical consensus: systemic steroids lack definitive indications and should be avoided. *Systemic steroids are contraindicated in all forms of psoriasis* - While systemic steroids are strongly discouraged, the absolute term "contraindicated in **all forms**" is **too extreme**. - There may be rare emergency situations where short-term use under specialist care is considered when safer alternatives are unavailable. - The statement overstates the position; "no definitive indication" is more medically accurate. *Only as bridge therapy in rare cases* - Bridge therapy with systemic steroids is **not recommended** in psoriasis due to high risk of disease exacerbation. - Unlike other inflammatory conditions, psoriasis responds poorly to steroid withdrawal, making bridge therapy particularly dangerous. *Emergency situations under specialist supervision only* - This suggests systemic steroids have a defined role in emergencies, which is **misleading**. - Even in urgent situations, alternative treatments like **cyclosporine**, **methotrexate**, or **biologics** are strongly preferred. - The rare exceptions don't constitute a "definitive indication."
Question 2: In which of the following conditions is phototherapy, specifically ultraviolet light therapy, useful for treatment?
- A. Psoriasis (Correct Answer)
- B. Tinea corporis
- C. Pemphigus
- D. PMLE
Explanation: ***Psoriasis*** - **Phototherapy** (narrowband UVB, broadband UVB, or PUVA) is a **well-established first-line treatment** for **moderate-to-severe psoriasis**. - It works by **suppressing overactive immune cells** in the skin, reducing inflammation and decreasing keratinocyte proliferation. - **Direct therapeutic effect** on active psoriatic lesions makes this the primary indication for phototherapy in dermatology. *Tinea corporis* - **Tinea corporis** is a **superficial fungal infection** (dermatophytosis) of the skin. - Requires **antifungal medications** (topical azoles or oral terbinafine/griseofulvin) for treatment. - **Phototherapy has no antifungal activity** and is not used for this condition. *Pemphigus* - **Pemphigus** is an **autoimmune blistering disease** with intraepidermal acantholysis. - Treatment requires **systemic immunosuppression** (corticosteroids, rituximab, azathioprine). - **Phototherapy is not indicated** and could potentially worsen the condition. *PMLE* - **Polymorphous light eruption (PMLE)** is a common **photosensitivity disorder**. - While **prophylactic photohardening** (gradual controlled UV exposure) can be used to build tolerance **before sun exposure season**, this is a **preventative desensitization strategy**, not treatment of active disease. - Unlike psoriasis, phototherapy does **not treat active PMLE lesions** and can trigger flares if not done properly. - The primary approach for active PMLE is **sun avoidance, sun protection, and topical corticosteroids**.
Question 3: PUVA therapy is used in all except:
- A. Psoriasis
- B. Vitiligo
- C. Mycosis fungoides
- D. Melasma (Correct Answer)
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.
Question 4: In which of the following conditions does IOL implantation after cataract surgery require the greatest caution and specialized management?
- A. Fuchs' heterochromic iridocyclitis
- B. Psoriatic arthritis
- C. Reiter's syndrome
- D. Juvenile rheumatoid arthritis (Correct Answer)
Explanation: ***Juvenile rheumatoid arthritis*** - Patients with **juvenile rheumatoid arthritis (JRA)**, particularly those with **pauciarticular JRA** and **ANA positivity**, are at high risk for developing chronic uveitis, which can lead to significant cataract formation and severe postoperative complications. - Due to the high risk of severe postoperative inflammation, glaucoma, and vision loss, IOL implantation in JRA patients requires extensive preoperative optimization of inflammation and careful intraoperative/postoperative management. *Fuchs' heterochromic iridocyclitis* - This condition presents with chronic, low-grade, **non-granulomatous anterior uveitis** and often leads to cataract formation. - While IOL implantation in these patients is generally well-tolerated, it does not pose the same high risk of severe postoperative inflammation and complications as seen in JRA-associated uveitis. *Psoriatic arthritis* - Psoriatic arthritis can be associated with acute anterior uveitis, but it typically presents as an acute, intermittent inflammation. - The risk of chronic, severe uveitis leading to complex cataract surgery and significant postoperative complications is not as consistently high or as severe as in JRA. *Reiter's syndrome* - Reiter's syndrome (now part of **reactive arthritis**) is another seronegative spondyloarthropathy that can cause acute anterior uveitis. - Similar to psoriatic arthritis, the uveitis is usually acute and self-limiting, and while ocular inflammation needs to be controlled, the risk profile for IOL implantation is not as challenging as in JRA.
Question 5: Dose of vitamin A for an 18 month old baby, with keratomalacia, weighing 10 kg is?
- A. 1,00,000 IU
- B. 50,000 IU
- C. 5,00,000 IU
- D. 2,00,000 IU (Correct Answer)
Explanation: **2,00,000 IU** - For children 12 months of age and older with **keratomalacia** due to vitamin A deficiency, the recommended dose is **200,000 IU** orally, given immediately. - This dose should be repeated the next day and again after four weeks to replenish stores and prevent recurrence. *1,00,000 IU* - This dose is typically recommended for infants **aged 6 to 11 months** with **clinical vitamin A deficiency**, including keratomalacia. - It is insufficient for an 18-month-old child with active keratomalacia. *50,000 IU* - This dose is usually given to infants **under 6 months** of age with clinical signs of **vitamin A deficiency**. - It is too low for an 18-month-old baby with keratomalacia. *5,00,000 IU* - This dose is excessively high and potentially toxic for an 18-month-old child. - Vitamin A toxicity can lead to adverse effects, including **increased intracranial pressure** and liver damage.
Question 6: The most common mechanism of resistance to drugs in Staphylococcus is
- A. Transformation
- B. Transduction (Correct Answer)
- C. Episomes
- D. Conjugation
Explanation: ***Correct Option: Transduction*** - **Transduction** is the transfer of genetic material via **bacteriophages** and is the **most common mechanism** of horizontal gene transfer in *Staphylococcus aureus*. - Bacteriophages play a crucial role in disseminating **antibiotic resistance genes** in staphylococci, including genes for **methicillin resistance (mecA)**, **toxins**, and **beta-lactamase**. - Phage-mediated transfer is responsible for spreading many **virulence factors** and **resistance determinants** among staphylococcal populations. *Incorrect Option: Episomes* - **Episomes** are plasmids capable of integrating into the bacterial chromosome or existing autonomously. - While episomes can **carry resistance genes**, they are a **genetic element**, not a **mechanism of transfer**. - The question asks about the mechanism, not the vehicle carrying resistance genes. *Incorrect Option: Transformation* - **Transformation** involves uptake of **naked DNA** from the environment. - *Staphylococcus* species are **not naturally competent** for transformation under normal conditions. - This is not a significant mechanism of resistance acquisition in staphylococci. *Incorrect Option: Conjugation* - **Conjugation** requires direct cell-to-cell contact through a **conjugative pilus**. - While possible in *Staphylococcus*, it is **less common** compared to transduction. - Conjugation is more characteristic of **Gram-negative bacteria** and enterococci among Gram-positives.
Question 7: All of the following are adverse effects of nicotinic acid except:
- A. Liver dysfunction
- B. Vasodilation
- C. Hyperpigmentation
- D. Pancreatitis (Correct Answer)
Explanation: ***Pancreatitis*** - **Pancreatitis** is not a commonly reported adverse effect of nicotinic acid (niacin) therapy. - While other gastrointestinal side effects like nausea and vomiting can occur, pancreatic inflammation is not characteristic. *Vasodilation* - **Cutaneous flushing** and **vasodilation** are very common adverse effects of nicotinic acid, mediated by prostaglandin release. - This effect can cause a sensation of warmth, redness, and itching, especially at the start of therapy. *Liver dysfunction* - **Liver dysfunction**, including elevated liver enzymes and rare cases of **hepatotoxicity**, can occur with high doses of nicotinic acid. - Regular monitoring of liver function tests is recommended for patients on niacin therapy. *Hyperpigmentation* - **Hyperpigmentation**, particularly **acanthosis nigricans**, is a known cutaneous side effect of nicotinic acid. - This typically presents as dark, velvety patches on the skin, especially in skin fold areas.
Question 8: Vitamin D analogues (such as calcitriol and calcipotriol) are useful in the treatment of:
- A. Pemphigus
- B. Leprosy
- C. Psoriasis (Correct Answer)
- D. Lichen planus
Explanation: ***Psoriasis*** - **Vitamin D analogues** such as calcipotriol and calcitriol help treat psoriasis by **inhibiting keratinocyte proliferation** and promoting their differentiation, reducing scale and plaque formation. - They also have **anti-inflammatory properties** that help alleviate the characteristic redness and inflammation seen in psoriatic plaques. - These are commonly used as **topical treatments** for mild to moderate plaque psoriasis. *Pemphigus* - This is an **autoimmune blistering disease** characterized by **antibodies against desmoglein**, leading to loss of cell-cell adhesion in the epidermis. - Treatment primarily involves **systemic corticosteroids** and immunosuppressants, not vitamin D analogues. *Leprosy* - **Leprosy** is a chronic infectious disease caused by **Mycobacterium leprae**, primarily affecting the skin, nerves, upper respiratory tract, eyes, and testes. - Treatment involves **multi-drug therapy (MDT)** with antibiotics like dapsone, rifampicin, and clofazimine, and vitamin D analogues are not indicated. *Lichen planus* - **Lichen planus** is a chronic inflammatory condition affecting the skin, hair, nails, and mucous membranes, characterized by **pruritic, polygonal, purple, planar papules and plaques**. - Treatment typically involves **topical or systemic corticosteroids**, retinoids, or phototherapy, not vitamin D analogues.
Question 9: Which of the following is NOT a complication of PUVA therapy?
- A. Premature aging of the skin
- B. Cataracts
- C. Skin cancers
- D. Exfoliative dermatitis (Correct Answer)
Explanation: **Explanation:** PUVA (Psoralen + Ultraviolet A) therapy involves the administration of a photosensitizer (8-methoxypsoralen) followed by exposure to UVA radiation. While it is an effective treatment for conditions like psoriasis and vitiligo, it carries specific long-term and short-term risks. **Why Exfoliative Dermatitis is the correct answer:** Exfoliative dermatitis (Erythroderma) is **not** a direct complication of PUVA. In fact, PUVA is often used as a *treatment* modality for certain types of exfoliative dermatitis, such as those caused by Mycosis Fungoides or Psoriasis. While PUVA can cause a "PUVA itch" or a phototoxic burn (erythema), it does not typically trigger generalized exfoliation. **Analysis of Incorrect Options:** * **Premature aging of the skin (Dermatoheliosis):** Chronic UVA exposure leads to the degradation of collagen and elastin fibers, resulting in wrinkles, lentigines, and telangiectasia. * **Cataracts:** Psoralens distribute to the lens of the eye. If the eyes are not protected with UVA-blocking sunglasses for 24 hours post-ingestion, UVA exposure can lead to lens opacification. * **Skin cancers:** PUVA is mutagenic. Long-term therapy significantly increases the risk of Non-Melanoma Skin Cancers (NMSC), particularly **Squamous Cell Carcinoma (SCC)**. **High-Yield Clinical Pearls for NEET-PG:** * **Most common acute side effect:** Erythema (phototoxicity) and pruritus. * **Most common long-term risk:** Squamous Cell Carcinoma (SCC) is more common than Basal Cell Carcinoma (BCC) in PUVA patients (reversing the usual ratio). * **PUVA Lentigines:** Distinctive, irregular pigmented macules that appear after chronic therapy. * **Contraindications:** Pregnancy, lactation, history of skin cancer (Xeroderma Pigmentosum), and severe hepatic/renal failure.
Question 10: A 12-year-old boy, after spending his holiday on a beach, develops pruritic hemorrhagic vesicles on his cheeks, ears, nose, and hands 12 hours after sun exposure. A week later, the lesions crusted and healed with permanent scars. What is the most probable diagnosis?
- A. Polymorphic light eruption
- B. Hydroa vacciniforme (Correct Answer)
- C. Actinic prurigo
- D. Persistent light reaction
Explanation: **Explanation:** The clinical presentation of a young boy with **hemorrhagic vesicles** on sun-exposed areas (cheeks, ears, nose, hands) that heal with **permanent scarring** (varioliform scars) is pathognomonic for **Hydroa vacciniforme (HV)**. **Why Hydroa vacciniforme is correct:** HV is a rare, chronic photodermatosis primarily affecting children. It is triggered by UVA radiation. The hallmark is the progression from erythema to vesicles/bullae, which become umbilicated and hemorrhagic, eventually forming necrotic crusts. The defining feature for NEET-PG is the healing process, which results in **depressed, "vacciniform" (smallpox-like) scars**. It is often associated with **Epstein-Barr Virus (EBV)** infection. **Why other options are incorrect:** * **Polymorphic Light Eruption (PMLE):** The most common photodermatosis. While it causes pruritic papules or vesicles, it **never heals with scarring**. * **Actinic Prurigo:** A variant of PMLE common in Native Americans. It presents with intensely pruritic, excoriated papules and nodules, often involving the lips (cheilitis) and conjunctiva, but does not typically present with hemorrhagic vesicles and varioliform scarring. * **Persistent Light Reaction:** Now classified under Chronic Actinic Dermatitis. It is an eczematous reaction seen in elderly males, where skin remains sensitive to light even without allergen exposure. **High-Yield Clinical Pearls for NEET-PG:** * **Action Spectrum:** UVA is the primary trigger for HV. * **Association:** Severe, systemic cases of HV are linked to **EBV-associated T-cell lymphoproliferative disorders**. * **Differential Diagnosis:** Must be distinguished from Erythropoietic Protoporphyria (EPP), which presents with immediate burning pain and waxy scarring, but lacks the hemorrhagic bullae of HV. * **Management:** Strict photoprotection; severe cases may require antimalarials or immunosuppressants.
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