Psoriasis — MCQs
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Which of the following layers is absent in psoriasis?
Koebner phenomenon is seen in which one of the following conditions?
A 45-year-old man presents with a 6-month history of scaly, erythematous plaques with silvery scales on his elbows, knees, and scalp. He reports occasional joint pain. His sister has similar skin problems. Examination reveals well-demarcated, erythematous plaques covered with silvery scales. Removal of scales causes pinpoint bleeding. Which of the following is most likely to be elevated in this condition?
Typical silvery scales of psoriasis are absent in –
A patient with psoriasis was started on systemic steroids. After stopping the treatment, the patient developed universally red scaly skin with plaques losing their margins all over his body. The most likely cause is –
Silver plaques are a feature of:
All are true about psoriasis except –
What is the most common type of psoriasis?
Dithranol ointment is used for:
All are nail changes seen in cases of psoriasis except:
Psoriasis Indian Medical PG Practice Questions and MCQs
Question 81: Which of the following layers is absent in psoriasis?
- A. A
- B. B (Correct Answer)
- C. C
- D. D
Explanation: ***B*** - The layer labeled 'B' corresponds to the **stratum granulosum (granular layer)** of the epidermis, which is **absent or markedly thinned in areas of parakeratosis** in psoriatic lesions. - The loss/absence of the stratum granulosum in psoriasis is a characteristic histological feature, particularly in regions showing parakeratosis (retention of nuclei in the stratum corneum). - This is considered the classic answer for "which layer is absent in psoriasis" in medical examinations. *A* - The layer labeled 'A' is the **stratum corneum (horny layer)**, which is actually **thickened** in psoriasis (hyperkeratosis) and shows **parakeratosis** (retention of nuclei). - The stratum corneum is not absent but rather abnormal, showing retained nuclei and increased thickness with scaling. *C* - The layer labeled 'C' represents the **stratum spinosum (prickle cell layer)**, which is significantly **thickened (acanthosis)** in psoriasis due to increased keratinocyte proliferation. - Acanthosis (thickening of the spinous layer) is a hallmark feature of psoriasis, not absence of this layer. *D* - The layer labeled 'D' points to the **stratum basale (basal layer)**, which contains actively dividing keratinocytes and is always present in the epidermis. - In psoriasis, the basal keratinocytes show increased proliferation and shortened cell cycle, leading to epidermal hyperplasia, but the layer is never absent.
Question 82: Koebner phenomenon is seen in which one of the following conditions?
- A. Behçet's disease
- B. Leprosy
- C. Acne Vulgaris
- D. Psoriasis (Correct Answer)
Explanation: ***Psoriasis*** - The **Koebner phenomenon**, or isomorphic response, is characteristic of psoriasis, where new psoriatic lesions appear on areas of **traumatized skin**. - This response is triggered by various forms of skin injury, such as scratches, surgical incisions, or sunburn. *Behçet's disease* - Behçet's disease is associated with **pathergy**, which is a hyper-reactivity to skin injury presenting as a sterile pustule or papule at the site of trauma, but it is distinct from the Koebner phenomenon. - While both involve skin reactivity to trauma, pathergy in Behçet's disease is typically a pustular response, whereas Koebner phenomenon in psoriasis results in typical psoriatic lesions. *Leprosy* - Leprosy is an infectious disease causing **skin lesions** and nerve damage, but it does not typically exhibit the Koebner phenomenon. - The skin manifestations in leprosy are primarily due to the infection with *Mycobacterium leprae* rather than an isomorphic response to trauma. *Acne Vulgaris* - Acne vulgaris is a common inflammatory skin condition involving hair follicles and sebaceous glands, characterized by **comedones, papules, pustules, and cysts**. - It is not associated with the Koebner phenomenon; new lesions arise from follicular blockage and inflammation, not from skin trauma in the same manner as psoriasis.
Question 83: A 45-year-old man presents with a 6-month history of scaly, erythematous plaques with silvery scales on his elbows, knees, and scalp. He reports occasional joint pain. His sister has similar skin problems. Examination reveals well-demarcated, erythematous plaques covered with silvery scales. Removal of scales causes pinpoint bleeding. Which of the following is most likely to be elevated in this condition?
- A. IL-10
- B. IL-17 (Correct Answer)
- C. IL-13
- D. IL-5
Explanation: ***IL-17*** - The patient's presentation with **scaly, erythematous plaques** with **silvery scales** on elbows, knees, and scalp, along with occasional joint pain, is highly suggestive of **psoriasis**. - **IL-17** is a key **pro-inflammatory cytokine** primarily produced by Th17 cells, playing a central role in the **pathogenesis of psoriasis** by promoting inflammation and keratinocyte proliferation. *IL-10* - **IL-10** is an **anti-inflammatory cytokine** that primarily functions to suppress immune responses and maintain immune tolerance. - While it can be present in some chronic inflammatory conditions, its primary role is to **downregulate inflammation**, making it unlikely to be significantly elevated as a driver of psoriasis. *IL-13* - **IL-13** is a cytokine strongly associated with **Type 2 immune responses** and allergic reactions, often seen in conditions like **asthma** and **atopic dermatitis**. - It is not a primary driver of the **Th17-mediated inflammatory processes** characteristic of psoriasis. *IL-5* - **IL-5** is primarily involved in the **growth and differentiation of eosinophils** and is a key cytokine in allergic inflammation and parasitic infections. - It does not play a significant role in the **immunopathology of psoriasis**.
Question 84: Typical silvery scales of psoriasis are absent in –
- A. Groin (Correct Answer)
- B. Knee
- C. Elbow
- D. Scalp
Explanation: ***Groin*** - Psoriasis in intertriginous areas like the **groin**, axilla, and skin folds presents as shiny, red, smooth patches without the typical silvery scales due to the moist environment. - This specific form is known as **inverse psoriasis** or flexural psoriasis. *Knee* - The knee is a common site for **plaque psoriasis**, which typically features well-demarcated, erythematous plaques covered with characteristic **silvery scales**. - Psoriasis on extensor surfaces like the knees and elbows is often dry and scaly. *Elbow* - Similar to the knee, the elbow is a classic location for **plaque psoriasis**, exhibiting the characteristic **silvery scales** over erythematous plaques. - These lesions often result from recurrent microtrauma on extensor surfaces. *Scalp* - **Scalp psoriasis** is common and manifests as thick, silvery-white scales that can extend beyond the hairline. - While it can be quite thick and adherent, the characteristic **silvery scales** are typically present.
Question 85: A patient with psoriasis was started on systemic steroids. After stopping the treatment, the patient developed universally red scaly skin with plaques losing their margins all over his body. The most likely cause is –
- A. Pustular psoriasis
- B. Erythrodermic psoriasis (Correct Answer)
- C. Drug induced reaction
- D. Bacterial infection
Explanation: ***Erythrodermic Psoriasis*** - This condition is characterized by **widespread erythema** and scaling affecting over 90% of the body surface, often with a loss of distinct plaque margins. - The sudden withdrawal of **systemic corticosteroids** in patients with psoriasis is a well-known trigger for erythrodermic psoriasis. *Pustular psoriasis* - This form presents with widespread or localized pustules, often on an erythrematous base, and may be accompanied by fever and systemic symptoms. - While it can be severe, the primary described feature here is **universal redness and scaling with plaque confluence**, not predominant pustule formation. *Drug induced reaction* - While drugs can induce or exacerbate psoriasis, the specific trigger described (withdrawal of systemic steroids) points more directly to a rebound phenomenon of the underlying psoriasis. - A drug-induced reaction would typically be an *initial* eruption or a different morphology, not a flare of pre-existing psoriasis due to *cessation* of treatment. *Bacterial infection* - A bacterial infection might cause redness, scaling, and inflammation, but it would typically be accompanied by signs of infection like fever, purulence, or pus. - The described condition is a direct rebound phenomenon after steroid withdrawal, not primarily an infective process.
Question 86: Silver plaques are a feature of:
- A. Psoriasis (Correct Answer)
- B. Vitiligo
- C. Lichen planus
- D. Albinism
Explanation: ***Psoriasis*** - **Psoriasis** is characterized by erythematous plaques covered with thick, silvery scales, typically on extensor surfaces. - These **silvery plaques** are a hallmark clinical feature due to accelerated epidermal cell turnover. *Vitiligo* - **Vitiligo** presents as **depigmented macules and patches** with well-defined borders, not silvery plaques. - It is an autoimmune condition causing the destruction of **melanocytes**, leading to loss of skin color. *Lichen planus* - **Lichen planus** typically manifests as **pruritic, polygonal, purple, planar papules and plaques** (the 6 Ps). - It does not involve silvery scales but may show **Wickham's striae**, which are fine white lines on the surface. *Albinism* - **Albinism** is a genetic condition characterized by a **lack of melanin pigment** in the skin, hair, and eyes. - This results in very fair skin, white hair, and light-colored eyes, not silvery plaques.
Question 87: All are true about psoriasis except –
- A. Auspitz sign positive
- B. Parakeratosis & acanthosis
- C. Joint involvement in 5–10% (Correct Answer)
- D. Pitting of nails
- E. Koebner phenomenon
Explanation: ***Joint involvement in 5–10%*** - While **psoriasis** is a skin condition, it can involve the joints in about **30% of patients**, leading to **psoriatic arthritis**. - Therefore, stating that joint involvement occurs in only **5-10%** is incorrect, as the percentage is significantly higher. - This is the **FALSE statement** in this EXCEPT question. *Auspitz sign positive* - The **Auspitz sign** (pinpoint bleeding when scales are removed) is a classic feature of psoriasis. - It occurs due to the proximity of dilated capillaries to the thinned suprapapillary epidermis. - This is a **TRUE statement**. *Parakeratosis & acanthosis* - **Parakeratosis** (retention of nuclei in the stratum corneum) and **acanthosis** (epidermal hyperplasia) are classic histopathological features of psoriasis. - These features reflect the **rapid cell turnover** and **thickening of the epidermis** characteristic of psoriatic plaques. - This is a **TRUE statement**. *Pitting of nails* - **Nail pitting** is a common manifestation of psoriasis, affecting up to **50% of patients** with chronic plaque psoriasis and **80% of patients with psoriatic arthritis**. - Other nail changes include **onycholysis**, **subungual hyperkeratosis**, and discoloration. - This is a **TRUE statement**. *Koebner phenomenon* - **Koebner phenomenon** (isomorphic response) is the development of psoriatic lesions at sites of trauma or injury. - This is seen in approximately **25% of patients** with psoriasis and is a well-recognized clinical feature. - This is a **TRUE statement**.
Question 88: What is the most common type of psoriasis?
- A. Guttate psoriasis
- B. Inverse psoriasis
- C. Psoriasis vulgaris (Correct Answer)
- D. Pustular psoriasis
Explanation: ***Psoriasis vulgaris*** - Also known as **plaque psoriasis**, this is the most prevalent form, accounting for approximately 80-90% of all psoriasis cases. - It characteristically presents with well-demarcated, erythematous plaques covered by **silvery scales**, commonly on the extensor surfaces. *Guttate psoriasis* - This form is characterized by **small, drop-like lesions** that appear suddenly on the trunk and proximal extremities. - It often follows a **streptococcal infection** and is much less common than plaque psoriasis. *Inverse psoriasis* - This variant affects **skin folds** such as axillae, groin, and inframammary areas, presenting as smooth, red, inflamed patches. - Unlike typical psoriasis, it usually **lacks scaling** due to the moist environment and represents a less common form. *Pustular psoriasis* - Characterized by the presence of **sterile pustules** on erythematous skin, this is a less common and often more severe form of psoriasis. - It can be localized or generalized and may be triggered by certain medications or infections.
Question 89: Dithranol ointment is used for:
- A. Pityriasis
- B. Psoriasis (Correct Answer)
- C. Pyoderma
- D. Herpes zoster
Explanation: ***Psoriasis*** - Diathronol is a synonym for **dithranol**, a topical medication primarily used to treat **chronic plaque psoriasis**. - It works by inhibiting cell proliferation and normalization of keratinization, reducing the characteristic scaling and inflammation of psoriasis. *Pityriasis* - This is a general term for various skin conditions presenting with fine scales; while some forms may be treated with different topical agents, **dithranol is not a first-line treatment** for most pityriasis types. - Pityriasis Versicolor, for example, is caused by fungus and treated with antifungals. *Pyoderma* - Pyoderma refers to **bacterial skin infections** characterized by pus, such as impetigo or ecthyma. - Treatments for pyoderma typically involve **antibiotics**, either topical or systemic, and not dithranol. *Herpes zoster* - Herpes zoster, or **shingles**, is a **viral infection** caused by the varicella-zoster virus. - Treatment involves **antiviral medications** (e.g., acyclovir, valacyclovir) and sometimes pain management, not dithranol.
Question 90: 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.
Practice by Chapter
Pathophysiology of Psoriasis
Practice Questions
Psoriasis Vulgaris
Practice Questions
Guttate Psoriasis
Practice Questions
Erythrodermic Psoriasis
Practice Questions
Pustular Psoriasis
Practice Questions
Palmoplantar Psoriasis
Practice Questions
Nail Psoriasis
Practice Questions
Scalp Psoriasis
Practice Questions
Psoriatic Arthritis
Practice Questions
Topical Therapy for Psoriasis
Practice Questions
Systemic Therapy for Psoriasis
Practice Questions
Phototherapy and Biologics for Psoriasis
Practice Questions
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