Scalp Psoriasis — MCQs
What is the primary condition for which calcitriol is used as a treatment?
Koebner's phenomenon is seen in all except
The following is an important feature of psoriasis:
In which of the following conditions is the Koebner phenomenon most commonly observed?
Match the following scale types with their lesions. | Scales | Lesions | | :-- | :-- | | 1. Collarette scales | a. Pityriasis versicolour | | 2. Silvery scales | b. Pityriasis rosea | | 3. Mica-like scales | c. Psoriasis | | 4. Branny scales | d. Pityriasis lichenoides |
A 30-year-old male presented with silvery scales on elbow and knee, that bleed on removal. The probable diagnosis is:
All are nail changes seen in cases of psoriasis except:
A 54-year-old man presents with well-demarcated scaly plaques on the extensor surfaces of elbows and knees. The scales are silvery-white in appearance. What is the most likely diagnosis?
All are true about psoriasis except:
A patient with psoriasis who was started on systemic steroids develops generalized pustules all over the body after stopping treatment. What is the most likely cause?
Scalp Psoriasis Indian Medical PG Practice Questions and MCQs
Question 1: What is the primary condition for which calcitriol is used as a treatment?
- A. Pemphigus
- B. Secondary hyperparathyroidism (Correct Answer)
- C. Lichen planus
- D. Leprosy
Explanation: Secondary hyperparathyroidism - Calcitriol is the active form of vitamin D (1,25-dihydroxyvitamin D₃), and it is crucial for regulating calcium and phosphate levels in the body [1]. - In secondary hyperparathyroidism, often seen in chronic kidney disease (CKD), the kidneys cannot convert vitamin D to its active form, leading to hypocalcemia and increased PTH secretion [1], [2]. - Calcitriol supplementation helps to increase calcium absorption from the gut and suppress the release of parathyroid hormone (PTH), thereby treating the underlying cause of secondary hyperparathyroidism [1], [2]. - This is the primary therapeutic indication for calcitriol in clinical practice. Lichen planus - This is a chronic inflammatory condition affecting the skin, hair, nails, and mucous membranes - Typically treated with corticosteroids or other immunosuppressants - Calcitriol has no primary role in the treatment of lichen planus; its therapeutic applications are predominantly related to calcium and bone metabolism Pemphigus - Pemphigus is a group of rare autoimmune blistering diseases that affect the skin and mucous membranes - Primary treatment involves immunosuppressants like corticosteroids, often in high doses - Calcitriol is not indicated for the treatment of pemphigus, as its mechanism of action is unrelated to the autoimmune processes characteristic of this disease Leprosy - Leprosy is a chronic infectious disease caused by the bacterium Mycobacterium leprae - Treated with multi-drug therapy (MDT), which includes antibiotics like rifampicin, dapsone, and clofazimine - Calcitriol is not an antibiotic and therefore has no role in treating the bacterial infection responsible for leprosy
Question 2: Koebner's phenomenon is seen in all except
- A. Psoriasis
- B. Warts
- C. Tinea corporis (Correct Answer)
- D. Molluscum contagiosum
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.
Question 3: The following is an important feature of psoriasis:
- A. Erythematous macules
- B. Crusting
- C. Silvery Scaling (Correct Answer)
- D. Coarse bleeding
Explanation: ***Silvery Scaling*** - **Silvery scaling** is a hallmark clinical feature of **psoriasis**, resulting from the rapid turnover of skin cells. - These scales often appear on **erythematous plaques** and can be easily scraped off, sometimes revealing pinpoint bleeding underneath (**Auspitz sign**). *Erythematous macules* - While psoriasis does involve **erythema** (redness), the primary lesions are typically **plaques**, not macules (flat, discolored spots). - Macules are seen in other dermatological conditions such as drug eruptions or early viral exanthems, but not as the definitive feature of psoriasis. *Crusting* - **Crusting** is a feature of conditions involving exudation and drying of serum, blood, or pus, such as **impetigo** or **eczema** with secondary infection. - It is not a characteristic primary lesion of psoriasis, although secondary infection of psoriatic plaques could theoretically lead to crusting. *Coarse bleeding* - **Coarse bleeding** is not a primary feature of psoriasis; however, when psoriatic scales are removed, pinpoint bleeding known as the **Auspitz sign** can occur. - This is distinct from frank, coarse bleeding and is a diagnostic clue rather than a characteristic lesion in itself.
Question 4: 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
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
Question 5: Match the following scale types with their lesions. | Scales | Lesions | | :-- | :-- | | 1. Collarette scales | a. Pityriasis versicolour | | 2. Silvery scales | b. Pityriasis rosea | | 3. Mica-like scales | c. Psoriasis | | 4. Branny scales | d. Pityriasis lichenoides |
- A. 1-d, 2-c, 3-a, 4-b
- B. 1-c, 2-b, 3-d, 4-a
- C. 1-a, 2-b, 3-d, 4-c
- D. 1-b, 2-c, 3-d, 4-a (Correct Answer)
Explanation: ***1-b, 2-c, 3-d, 4-a*** - **Collarette scales** are pathognomonic of **Pityriasis rosea**, appearing as fine, trailing scales around the periphery of oval lesions in a "Christmas tree" distribution. - **Silvery scales** are the classic hallmark of **Psoriasis**, presenting as thick, adherent, silvery-white scales overlying well-demarcated erythematous plaques. - **Mica-like scales** are characteristic of **Pityriasis lichenoides**, appearing as thick, shiny, adherent scales that can be peeled off like mica sheets. - **Branny scales** are typical of **Pityriasis versicolor**, presenting as fine, powdery scales caused by **Malassezia** yeast overgrowth. *1-d, 2-c, 3-a, 4-b* - Incorrectly matches **collarette scales with Pityriasis lichenoides**, which typically presents with mica-like scales, not collarette scales. - Misassociates **mica-like scales with Pityriasis versicolor**, which characteristically has branny (fine, powdery) scales. *1-c, 2-b, 3-d, 4-a* - Wrongly pairs **collarette scales with Psoriasis**, which is known for thick silvery scales, not peripheral collarette scales. - Incorrectly matches **silvery scales with Pityriasis rosea**, which has collarette scales at lesion periphery, not silvery scales. *1-a, 2-b, 3-d, 4-c* - Falsely associates **collarette scales with Pityriasis versicolor**, which has branny scales from yeast infection, not collarette scales. - Mismatches **branny scales with Psoriasis**, which has characteristic thick silvery scales, not fine powdery scales.
Question 6: A 30-year-old male presented with silvery scales on elbow and knee, that bleed on removal. The probable diagnosis is:
- A. Secondary syphilis
- B. Psoriasis (Correct Answer)
- C. Pityriasis
- D. Seborrhoeic dermatitis
Explanation: ***Psoriasis*** - The presence of **silvery scales** on the elbows and knees, which **bleed upon removal** (Auspitz sign), is a classic presentation of **plaque psoriasis**. - Psoriasis is a chronic inflammatory skin condition characterized by **accelerated epidermal turnover**. *Secondary syphilis* - Secondary syphilis typically presents with a **generalized maculopapular rash**, which can affect the palms and soles, but it does not usually feature silvery scales or the Auspitz sign. - Other common symptoms of secondary syphilis include **fever, lymphadenopathy, and condyloma lata**. *Pityriasis* - **Pityriasis rosea** is characterized by an oval, fawn-colored, scaly rash, often preceded by a **herald patch**, and usually resolves spontaneously. It does not typically present with silvery scales or bleeding on removal. - **Pityriasis versicolor** is caused by yeast and presents as hypopigmented or hyperpigmented macules with fine scales, commonly on the trunk, not silvery scales on elbows and knees. *Seborrhoeic dermatitis* - Seborrhoeic dermatitis involves greasy, yellowish scales on red skin, typically affecting areas rich in sebaceous glands like the scalp, face (nasolabial folds, eyebrows), and chest. - It does not present with silvery scales or the Auspitz sign, which are specific to psoriasis.
Question 7: All are nail changes seen in cases of psoriasis except:
- A. Subungual hyperkeratosis
- B. Oil drop sign
- C. Mees lines (Correct Answer)
- D. Pitting
Explanation: ***Mees lines*** - **Mees lines** (or Aldrich-Mees lines) are **transverse white bands** that appear in the nail plate. - They are typically associated with **heavy metal poisoning** (e.g., arsenic), chemotherapy, or systemic illnesses, not psoriasis. *Subungual hyperkeratosis* - This is a common finding in **psoriasis**, characterized by the **thickening of the nail bed** due to excessive keratin production. - It leads to lifting of the nail plate from the nail bed. *Oil drop sign* - The **oil drop sign** (or salmon patch) is a classic psoriatic nail change, presenting as a **translucent, yellowish-red discoloration** under the nail plate. - It is due to psoriasis of the nail bed. *Pitting* - **Nail pitting** refers to the presence of **small depressions or pits** on the nail surface. - It results from defective keratinization of the nail matrix and is a characteristic sign of nail psoriasis.
Question 8: A 54-year-old man presents with well-demarcated scaly plaques on the extensor surfaces of elbows and knees. The scales are silvery-white in appearance. What is the most likely diagnosis?
- A. Eczema
- B. Psoriasis (Correct Answer)
- C. Lichen planus
- D. Pityriasis rosea
Explanation: ***Psoriasis*** - **Psoriasis** classically presents with **scaly plaques** that often appear on the **extensor surfaces** like elbows and knees. - The scales are typically **silvery-white** and can be associated with itching or discomfort. *Eczema* - **Eczema** (atopic dermatitis) typically presents with **pruritic (itchy)**, **erythematous (red)**, and sometimes **weeping lesions**, often in flexural areas like the antecubital and popliteal fossae. - While it can be scaly, the scales are usually finer and less prominent than those seen in psoriasis, and it often presents on **flexor surfaces**. *Lichen planus* - **Lichen planus** is characterized by **pruritic, purple, polygonal, planar papules and plaques** (the "6 Ps"), often found on flexural surfaces, wrists, and ankles. - It does not typically present with the thick, silvery scales on extensor surfaces seen in this case. *Pityriasis rosea* - **Pityriasis rosea** typically begins with a **herald patch**, followed by an eruption of smaller, oval, scaly patches that follow the skin Langer's lines, often described as a "Christmas tree" pattern on the trunk. - It is usually self-limiting and rarely involves the thick, scaly plaques on extensor surfaces seen in psoriasis.
Question 9: All are true about psoriasis except:
- A. Parakeratosis & acanthosis
- B. Pitting of nails
- C. Very pruritic (Correct Answer)
- D. Joint involvement in 5–30%
Explanation: ***Very pruritic*** - While psoriasis can be itchy, it is generally not characterized as "very pruritic" compared to other dermatological conditions like **eczema** or **scabies**. - **Pruritus** in psoriasis tends to be mild to moderate, and it is not a defining characteristic that differentiates it from other skin disorders. *Parakeratosis & acanthosis* - **Parakeratosis** (retention of nuclei in the stratum corneum) and **acanthosis** (epidermal hyperplasia) are classic histopathological hallmarks of psoriasis. - These features reflect the rapid epidermal turnover characteristic of the condition. *Pitting of nails* - **Nail pitting**, onycholysis, and subungual hyperkeratosis are common and characteristic manifestations of psoriasis, affecting up to 50% of patients. - These nail changes are highly indicative of **psoriatic involvement**. *Joint involvement in 5–10%* - **Psoriatic arthritis**, involving inflammation of the joints, affects approximately 5-30% of individuals with psoriasis. - This statistic makes joint involvement a significant comorbidity of psoriasis.
Question 10: A patient with psoriasis who was started on systemic steroids develops generalized pustules all over the body after stopping treatment. What is the most likely cause?
- A. Bacterial infection
- B. Septicemia
- C. Pustular psoriasis due to steroid withdrawal (Correct Answer)
- D. Drug-induced pustular psoriasis
Explanation: ***Pustular psoriasis due to steroid withdrawal*** - **Systemic steroid withdrawal** can precipitate a severe flare of psoriasis, often leading to generalized **pustular psoriasis**. - This is a well-known phenomenon where the suppression of the immune system by steroids is abruptly removed, causing a rebound inflammatory response. *Drug-induced pustular psoriasis* - While certain drugs can induce pustular psoriasis, the scenario specifically highlights the **cessation of systemic steroids** as the trigger. - This option doesn't pinpoint the direct causal effect of stopping the medication. *Bacterial infection* - Although pustules can be associated with bacterial infections, the **generalized nature** and history of **steroid withdrawal** in a patient with psoriasis make an infectious cause less likely as the primary trigger. - A bacterial infection would typically present with signs of local infection (e.g., warmth, tenderness, fever) alongside the pustules, which are not exclusively mentioned here. *Septicemia* - **Septicemia** is a severe bloodstream infection and would present with systemic signs of illness such as high fever, chills, hypotension, and organ dysfunction, which are not described. - While pustules can sometimes occur in severe infections, the clinical context strongly points to a dermatological reaction to medication changes, not a systemic infection.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free