Photoaging — MCQs
Chemical peeling is indicated in all of the following except
In which of the following conditions is phototherapy, specifically ultraviolet light therapy, useful for treatment?
What is the diagnosis for this patient with end-stage renal disease who developed skin changes after an imaging procedure?
A patient presents with a skin rash that is exaggerated on sun exposure. What is the repair mechanism involved in this condition?
A young boy with oily skin presents with acne as shown. What is the appropriate treatment?
Which of the following statements is not correct regarding sebaceous cyst?
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?
Psoralen plus ultraviolet A (PUVA) therapy is useful in which of the following conditions?
Psoralen is used in the treatment of:
Photoaging 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: 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: What is the diagnosis for this patient with end-stage renal disease who developed skin changes after an imaging procedure?
- A. Porphyria cutanea tarda
- B. Nephrogenic systemic fibrosis (Correct Answer)
- C. Calciphylaxis
- D. Actinic elastosis
Explanation: **Nephrogenic systemic fibrosis** * This condition is strongly associated with exposure to **gadolinium-based contrast agents** in patients with severe **renal insufficiency** or **end-stage renal disease (ESRD)**. * It presents with **skin thickening** and hardening, often involving the extremities and trunk, which can progress to joint contractures and immobility. *Porphyria cutanea tarda* * This is a **disorder of heme synthesis** characterized by **fragile skin**, **blistering**, and **hypertrichosis** in sun-exposed areas [1]. * While it can be associated with liver disease and sometimes seen in patients with ESRD, it is not directly linked to contrast media exposure [1]. *Calciphylaxis* * This severe and rare syndrome involves **vascular calcification** and **skin necrosis**, predominantly seen in patients with ESRD. * It typically presents as painful, violaceous skin lesions that progress to ulcers, and while connected to ESRD, it is not triggered by imaging procedures. *Actinic elastosis* * This condition refers to **degeneration of elastic tissue in the skin** due to chronic and excessive **sun exposure**. * It is characterized by thickened, wrinkled, and yellowed skin and is not related to kidney disease or contrast agent exposure.
Question 4: A patient presents with a skin rash that is exaggerated on sun exposure. What is the repair mechanism involved in this condition?
- A. Nucleotide excision repair (Correct Answer)
- B. Base excision repair
- C. Mismatch repair
- D. Double stranded DNA break repair
Explanation: ***Nucleotide excision repair*** - This mechanism is responsible for repairing **bulky lesions** in DNA, such as **pyrimidine dimers** caused by **UV radiation** from sun exposure. - Patients with defects in nucleotide excision repair (e.g., **xeroderma pigmentosum**) are highly sensitive to sunlight and develop skin rashes, pigment changes, and skin cancers. *Base excision repair* - This pathway primarily corrects **small damaged bases** that do not cause significant distortion of the DNA helix, such as deaminated, oxidized, or alkylated bases. - It does not primarily address the bulky lesions induced by UV light that cause exaggerated sun sensitivity. *Mismatch repair* - This system corrects errors, like **mismatched base pairs**, that are incorporated during DNA replication. - It is not directly involved in repairing DNA damage caused by environmental factors like UV radiation. *Double stranded DNA break repair* - This mechanism repairs **double-strand breaks** in DNA, which are highly deleterious lesions caused by ionizing radiation or oxidative stress. - While critical for genome stability, it is not the primary repair pathway for UV-induced DNA lesions or the direct cause of sun sensitivity.
Question 5: A young boy with oily skin presents with acne as shown. What is the appropriate treatment?
- A. Oral isotretinoin
- B. Oral steroid
- C. Topical retinoic acid (Correct Answer)
- D. Benzoyl peroxide
Explanation: ***Topical retinoic acid*** - The image shows **comedonal acne** with numerous small bumps, which typically responds well to topical retinoids like retinoic acid. - **Topical retinoids** work by normalizing follicular keratinization and reducing comedone formation, making them the **first-line treatment** for comedonal and mild to moderate inflammatory acne. - Retinoids are superior to other agents for comedonal acne due to their comedolytic properties. *Oral isotretinoin* - **Oral isotretinoin** is reserved for **severe cystic or nodular acne**, or acne that is unresponsive to other treatments, which does not appear to be the case here. - It has significant side effects and requires close monitoring, making it inappropriate for the initial treatment of mild to moderate acne. *Oral steroid* - **Oral steroids** are not a primary treatment for acne and are usually reserved for severe, **fulminant acne** (like acne conglobata) or to manage acute exacerbations of inflammatory acne due to their numerous side effects. - Their primary role is potent **anti-inflammatory action**, but they do not address the underlying pathogenesis of acne. *Benzoyl peroxide* - **Benzoyl peroxide** is effective against **inflammatory acne** due to its antibacterial and keratolytic properties. - While it can be used for comedonal acne and is often combined with retinoids for enhanced efficacy, **topical retinoids are preferred as monotherapy** for predominantly comedonal acne as shown in this image. - Benzoyl peroxide is particularly useful when there are inflammatory lesions (papules, pustules) present.
Question 6: Which of the following statements is not correct regarding sebaceous cyst?
- A. Found on hairy areas of the body
- B. Treatment is incision and drainage (Correct Answer)
- C. Not found on palms and soles
- D. It has a punctum
Explanation: ***Treatment is incision and drainage*** - The standard treatment for a sebaceous cyst (more accurately an **epidermoid cyst** or **pilar cyst**) is **surgical excision** of the entire cyst wall to prevent recurrence. - **Incision and drainage** only provides temporary relief by emptying the contents but leaves the cyst wall intact, leading to a high chance of the cyst refilling. *Found on hairy areas of the body* - This statement is generally correct as sebaceous cysts often arise from hair follicles and are common in **hair-bearing areas** like the scalp, face, neck, and trunk. - They occur due to the accumulation of **sebum** and keratin within a blocked or damaged sebaceous gland or hair follicle. *Not found on palms and soles* - This statement is correct because **palms and soles** generally **lack sebaceous glands** and hair follicles, hence sebaceous cysts are typically not found in these locations. - Cysts found in these areas are more likely to be **ganglion cysts** or other types of epidermal inclusion cysts. *It has a punctum* - This statement is often correct; many sebaceous cysts (especially epidermoid cysts) have a visible **central punctum** which represents the occluded pore from which the cyst originated. - This punctum is a **key diagnostic feature** and can sometimes exude a cheesy, foul-smelling material.
Question 7: 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 8: 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.
Question 9: Psoralen plus ultraviolet A (PUVA) therapy is useful in which of the following conditions?
- A. Vitiligo
- B. Mycosis fungoides
- C. Psoriasis
- D. All of the above (Correct Answer)
Explanation: **Explanation:** **PUVA (Psoralen + UVA)** therapy involves the administration of a photosensitizing agent (8-Methoxypsoralen) followed by exposure to long-wave ultraviolet A light (320–400 nm). The mechanism involves the formation of DNA photo-adducts, which inhibit DNA synthesis and induce apoptosis of hyperproliferating cells and T-lymphocytes. **Why "All of the Above" is Correct:** * **Psoriasis:** PUVA is a classic treatment for moderate-to-severe plaque psoriasis. It reduces the rapid turnover of keratinocytes and suppresses the local cutaneous immune response. * **Vitiligo:** Psoralens stimulate the migration and proliferation of melanocytes from the hair follicle reservoir to the depigmented skin, promoting repigmentation. * **Mycosis Fungoides (MF):** As a cutaneous T-cell lymphoma, MF is highly sensitive to the phototoxic effects of PUVA, which induces apoptosis in malignant T-cells infiltrating the epidermis. **Clinical Pearls for NEET-PG:** 1. **Mechanism:** Psoralens intercalate into DNA; UVA then causes **Type I (oxygen-independent)** reactions forming monoadducts/cross-links and **Type II (oxygen-dependent)** reactions forming free radicals. 2. **Dosage:** Oral psoralen is usually given **0.6 mg/kg**, 2 hours before UVA exposure. 3. **Side Effects:** Acute side effects include nausea and erythema. Long-term risks include **PUVA lentigines** and an increased risk of **Squamous Cell Carcinoma (SCC)**. 4. **Contraindication:** PUVA is contraindicated in patients with Xeroderma Pigmentosum, Lupus Erythematosus, and pregnancy. 5. **Current Trend:** Narrowband UVB (311 nm) has largely replaced PUVA for psoriasis and vitiligo due to a better safety profile, but PUVA remains superior for thick plaques and MF.
Question 10: Psoralen is used in the treatment of:
- A. Pemphigus
- B. Vitiligo (Correct Answer)
- C. Pityriasis alba
- D. Ichthyosis
Explanation: **Explanation:** **Psoralen** is a photosensitizing agent used in **PUVA (Psoralen + Ultraviolet A)** therapy. It belongs to the furocoumarin family and works by intercalating into DNA. Upon exposure to UVA light, it forms DNA cross-links, which inhibits keratinocyte proliferation and induces melanocyte stimulation. **Why Vitiligo is correct:** In Vitiligo, PUVA therapy is a classic treatment modality. It works by: 1. **Immunomodulation:** Suppressing the T-cell mediated destruction of melanocytes. 2. **Melanocyte Stimulation:** Promoting the migration of melanocytes from the hair follicle reservoir to the depigmented skin, leading to repigmentation. **Why other options are incorrect:** * **Pemphigus:** This is an autoimmune bullous disorder treated primarily with systemic corticosteroids and immunosuppressants (e.g., Rituximab, Azathioprine), not phototherapy. * **Pityriasis alba:** This is a mild form of dermatitis common in children, usually associated with atopy. It is treated with emollients and low-potency topical steroids; psoralens are not indicated. * **Ichthyosis:** This is a genetic disorder of keratinization characterized by fish-like scales. Treatment involves keratolytics (e.g., urea, lactic acid) and systemic retinoids. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Psoralens (e.g., 8-Methoxypsoralen) bind to pyrimidine bases (thymine) in DNA. * **Common Indications for PUVA:** Psoriasis (most common), Vitiligo, Mycosis Fungoides (CTCL), and Alopecia Areata. * **Side Effects:** Acute side effects include nausea and polymorphic light eruption. Long-term risks include **PUVA lentigines** and an increased risk of **Squamous Cell Carcinoma (SCC)**. * **Contraindication:** PUVA is contraindicated in patients with Xeroderma Pigmentosum, SLE, or a history of skin cancer.
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