Psoriasis Practice Questions

Q: What histological feature is most characteristic of psoriasis?

Munro microabscesses in stratum corneum. ***Munro microabscesses in stratum corneum*** - Munro microabscesses are characteristic accumulations of **neutrophils** within the **stratum corneum** in psoriasis. - Their presence is a key **histological feature** used in the diagnosis of psoriasis. *Parakeratosis with retained nuclei in stratum corneum* - **Parakeratosis** (retained nuclei in the stratum corneum) is a feature of psoriasis but is **not specific** to it; it can be seen in other inflammatory skin conditions. - While present, it doesn't serve as the sole or most definitive characteristic feature differentiating psoriasis from other conditions. *Acanthosis with elongated rete ridges* - **Acanthosis** (epidermal hyperplasia) with elongated rete ridges is a prominent histological finding in psoriasis. - However, similar epidermal changes can be observed in various other chronic inflammatory skin conditions, making it **less specific** than Munro microabscesses. *Spongiform pustules of Kogoj in stratum spinosum* - **Spongiform pustules of Kogoj** are collections of neutrophils predominantly found in the **stratum spinosum**. - While associated with some forms of psoriasis, particularly **pustular psoriasis**, they are not considered the universally characteristic feature of typical plaque psoriasis.

Q: A 54-year-old man presents with well-demarcated, erythematous plaques covered with silvery-white scales on the extensor surfaces of his elbows and knees. What is the most likely diagnosis?

Psoriasis. ***Psoriasis*** - **Psoriasis** classically presents with **scaly plaques** that often appear on the **extensor surfaces** such as the elbows and knees. - The scales are typically silvery-white and can be itchy or painful, consistent with the characteristic presentation of chronic plaque psoriasis. *Pityriasis rosea* - This condition presents with a **herald patch** followed by smaller, oval, pinkish-red patches with fine scales, often distributed in a **Christmas tree pattern** on the trunk. - It primarily affects the trunk and proximal extremities, rarely involving the extensor surfaces in the same way as psoriasis. *Eczema* - **Eczema**, particularly atopic dermatitis, typically presents with **itchy, erythematous patches** that are often ill-defined and can be dry or weeping. - While it can occur on extensor surfaces, it is more commonly found on flexural surfaces in adults and lacks the distinct, thick silvery scales characteristic of psoriasis. *Lichen planus* - **Lichen planus** is characterized by **pruritic, purple, polygonal, planar papules and plaques** (**the 6 P's**). - It usually affects the flexural surfaces, wrists, ankles, and oral mucosa, rather than predominantly presenting as scaly plaques on extensor surfaces.

Q: A 40-year-old male presents with erythematous scaly lesions on the extensor surfaces of his elbows and knees. The clinical diagnosis is confirmed by which sign?

Auspitz sign. ***Auspitz sign*** - The presence of **erythematous scaly lesions on extensor surfaces** is highly suggestive of **psoriasis**. - The **Auspitz sign** is specific to psoriasis; it refers to pinpoint bleeding after scaling is removed due to exposure of dilated capillaries in dermal papillae. *KOH smear* - A **KOH smear** is used to identify fungal elements in skin, hair, or nails. - It would be relevant if fungal infection were suspected, but not for the clinical picture of psoriasis. *Tzanck smear* - A **Tzanck smear** is used to detect multinucleated giant cells characteristic of herpes simplex or varicella-zoster virus infections. - It is not indicated for the diagnosis of psoriasis. *Skin biopsy* - While a **skin biopsy** can confirm psoriasis, it is typically reserved for atypical presentations or equivocal clinical findings. - The **Auspitz sign** provides a more immediate and clinically specific diagnostic confirmation for classic psoriasis lesions.

Q: A 50-year-old female presents with thickened, hyperkeratotic plaques on her palms and soles, accompanied by a positive Auspitz sign. What is the diagnosis?

Palmoplantar psoriasis. ***Palmoplantar psoriasis*** - This condition is characterized by **thickened, hyperkeratotic plaques** specifically on the **palms and soles**. - A **positive Auspitz sign** (pinpoint bleeding after scaling is removed) is a classic finding in **psoriasis**, further supporting this diagnosis. *Eczema* - While eczema can affect the palms and soles (dyshidrotic eczema), it typically presents with **vesicles, intense itching, redness**, and less defined plaques. - The **Auspitz sign is not present** in eczema. *Lichen planus* - Characterized by **pruritic, purple, polygonal, planar papules and plaques** (the 6 Ps), often on the flexural surfaces, wrists, and ankles. - It does not typically present with the specific hyperkeratotic plaques of palmoplantar psoriasis, nor does it have a positive Auspitz sign. *Pityriasis rubra pilaris* - This condition presents with **follicular papules** that coalesce into **salmon-colored plaques** with islands of unaffected skin. - It often involves generalized erythema and scaling but does not typically present as sharply demarcated hyperkeratotic plaques on the palms and soles, nor does it have a positive Auspitz sign.

Q: A 60-year-old woman presents with pruritic, erythematous plaques on her elbows and knees. A skin biopsy shows hyperkeratosis, parakeratosis, and neutrophils in the stratum corneum. What is the diagnosis?

Psoriasis. ***Psoriasis*** - The presentation of **pruritic, erythematous plaques** on the **extensor surfaces** (elbows and knees) is classic for **psoriasis**. - Histopathological findings of **hyperkeratosis**, **parakeratosis**, and **neutrophils in the stratum corneum** (Munro microabscesses) are characteristic of psoriasis. *Atopic dermatitis* - Typically presents with **pruritic, eczematous lesions** in flexural areas (e.g., antecubital and popliteal fossae), not usually on extensor surfaces. - Histology would show **spongiosis** (intercellular edema in the epidermis) and **lymphocytic infiltrate**, not prominent neutrophils in the stratum corneum. *Lichen planus* - Characterized by **pruritic, polygonal, purple, planar papules and plaques** (the "6 Ps"), often affecting the wrists, ankles, and oral mucosa. - Histology typically reveals a **sawtooth rete ridge pattern** and a **band-like lymphocytic infiltrate** at the dermo-epidermal junction. *Seborrheic dermatitis* - Usually presents with **greasy, yellowish scales** on erythematous skin in areas rich in sebaceous glands, such as the scalp, face, and chest. - Histology would show **spongiosis**, **psoriasiform hyperplasia**, and a **perivascular lymphocytic infiltrate** with **neutrophils around follicular openings**.

Q: A 45-year-old woman presents with chronic plaques on her elbows and knees accompanied by silvery scales. What is the most appropriate first-line treatment?

Topical steroids. **Topical Steroids** - For localized, chronic plaques like those seen in **psoriasis** on the elbows and knees, **topical corticosteroids** are the first-line treatment due to their anti-inflammatory properties. - They help reduce **redness, scaling, and itching**, providing effective symptom control for mild to moderate cases. *Oral Antibiotics* - **Oral antibiotics** are used to treat bacterial infections and have no role in the management of psoriasis, which is an **autoimmune inflammatory condition**. - There is no indication of infection (e.g., pus, fever, rapidly spreading cellulitis) in this presentation. *Phototherapy* - **Phototherapy** (e.g., UVB or PUVA) is an effective treatment for widespread or more severe psoriasis, but it is typically reserved when **topical therapies** are insufficient. - It is not usually considered the **first-line treatment** for localized plaques on elbows and knees. *Systemic Retinoids* - **Systemic retinoids** (like acitretin) are potent medications used for severe, widespread, or disabling psoriasis, especially pustular or erythrodermic forms. - They have significant **side effects** and require careful monitoring, making them unsuitable as a first-line treatment for localized plaques.

Q: A 50-year-old man presents with red, scaly patches on his scalp that bleed when scratched. This is indicative of which condition?

Psoriasis. ***Psoriasis*** - **Red, scaly patches** on the scalp, especially those that **bleed when scratched** (Auspitz sign), are classic signs of **psoriasis**. - Psoriasis is a **chronic autoimmune** skin condition characterized by accelerated skin cell turnover. *Seborrheic dermatitis* - Presents with **greasy, yellowish scales** and redness, often found in areas with high sebaceous gland activity like the scalp. - Unlike psoriasis, it typically does not exhibit significant bleeding when scratched. *Tinea capitis* - This is a **fungal infection** of the scalp, characterized by **scaly patches**, **hair loss**, and sometimes **black dots** from broken hairs. - It is often associated with itching but usually does not involve the prominent bleeding seen in psoriasis. *Lichen planus* - Characterized by **purplish, polygonal, planar, pruritic papules** and plaques, often on the flexor surfaces, but can affect the scalp. - Scalp involvement, known as lichen planopilaris, typically leads to **scarring alopecia** and does not present with red, scaly patches that bleed easily upon scratching.

Q: A 40-year-old male presents with chronic, relapsing pustular eruptions on the palms and soles, along with a history of smoking. What is the most likely diagnosis?

Palmoplantar pustulosis. ***Palmoplantar pustulosis*** - This condition is characterized by **chronic, relapsing sterile pustules** localized to the **palms and soles**, often associated with a history of **smoking**. - It is now considered a **distinct entity** separate from psoriasis, though it was historically classified as a variant of pustular psoriasis. The strong smoking association and typical palmoplantar distribution are key diagnostic features. *Pustular psoriasis* - Generalized pustular psoriasis presents with **widespread pustules** on erythematous skin beyond the palms and soles and can be accompanied by systemic symptoms such as fever and malaise. - Unlike palmoplantar pustulosis, it typically has a more acute presentation and lacks the exclusive palmoplantar distribution. *Dyshidrotic eczema* - Characterized by **deep-seated vesicles** (not true pustules) on the palms and soles, often intensely itchy. - Lesions are primarily **vesicular** before they rupture or dry, and lack the strong association with **smoking** seen in palmoplantar pustulosis. *Contact dermatitis* - Results from an **allergic or irritant reaction** to an external substance, leading to eczema, erythema, and vesicles in areas of contact. - Would typically have an **identifiable trigger** and would not primarily manifest as **sterile pustules** recurring chronically without clear exposure history.

Q: A 60-year-old woman presents with red, scaly patches on her arms that bleed easily when scratched. This is a classic sign of which condition?

Psoriasis. ***Psoriasis*** - **Red, scaly patches** that **bleed easily when scratched** (known as the **Auspitz sign**) are **pathognomonic** for psoriasis. - Psoriasis is a **chronic autoimmune** skin condition characterized by accelerated skin cell turnover. *Seborrheic dermatitis* - Characterized by **greasy, yellow scales** on erythematous skin, often in areas with high sebaceous gland activity like the scalp, face, and chest. - It is typically **not associated with the Auspitz sign** or easily bleeding lesions. *Actinic keratosis* - Presents as **rough, scaly patches** on sun-exposed skin and is considered a **precancerous lesion**. - While scaly, it generally does not exhibit the classic vivid redness or **Auspitz sign** seen in psoriasis. *Lichen planus* - Characterized by **pruritic, purple, polygonal, planar papules** and plaques, often on the flexor surfaces of the wrists and ankles. - It may cause Lacy white patterns on mucous membranes (Wickham's striae) and **does not typically bleed easily** when scratched.

Q: Woronoff's ring is specifically associated with which skin condition?

Psoriasis. ***Psoriasis*** - **Woronoff's ring** is a characteristic pale, blanching ring that can appear around resolving psoriatic plaques, especially after phototherapy or topical treatments. - It results from a local vasoconstriction or altered vascular response in the lesional skin as inflammation subsides. *Lichen planus* - Characterized by **purple, polygonal, pruritic papules and plaques**, often with **Wickham's striae** (fine white lines). - It does not present with Woronoff's ring. *Pityriasis rosea* - Presents with a **herald patch** followed by widespread small, oval, faint reddish-brown lesions arranged in a **"Christmas tree" pattern** on the trunk. - This condition is self-limiting and not associated with Woronoff's ring. *Pemphigus* - A group of **autoimmune blistering diseases** caused by antibodies against desmogleins, leading to **flaccid blisters** that rupture easily. - Clinical signs include Nikolsky's sign, but not Woronoff's ring.

Question 1

What histological feature is most characteristic of psoriasis?

Accepted Answer

Munro microabscesses in stratum corneum

Answer

Parakeratosis with retained nuclei in stratum corneum

Answer

Acanthosis with elongated rete ridges

Answer

Spongiform pustules of Kogoj in stratum spinosum

Question 2

A 54-year-old man presents with well-demarcated, erythematous plaques covered with silvery-white scales on the extensor surfaces of his elbows and knees. What is the most likely diagnosis?

Accepted Answer

Psoriasis

Answer

Pityriasis rosea

Answer

Eczema

Answer

Lichen planus

Question 3

A 40-year-old male presents with erythematous scaly lesions on the extensor surfaces of his elbows and knees. The clinical diagnosis is confirmed by which sign?

Accepted Answer

Auspitz sign

Answer

KOH smear

Answer

Tzanck smear

Answer

Skin biopsy

Question 4

A 50-year-old female presents with thickened, hyperkeratotic plaques on her palms and soles, accompanied by a positive Auspitz sign. What is the diagnosis?

Accepted Answer

Palmoplantar psoriasis

Answer

Eczema

Answer

Lichen planus

Answer

Pityriasis rubra pilaris

Question 5

A 60-year-old woman presents with pruritic, erythematous plaques on her elbows and knees. A skin biopsy shows hyperkeratosis, parakeratosis, and neutrophils in the stratum corneum. What is the diagnosis?

Accepted Answer

Psoriasis

Answer

Atopic dermatitis

Answer

Lichen planus

Answer

Seborrheic dermatitis

Question 6

A 45-year-old woman presents with chronic plaques on her elbows and knees accompanied by silvery scales. What is the most appropriate first-line treatment?

Accepted Answer

Topical steroids

Answer

Oral antibiotics

Answer

Phototherapy

Answer

Systemic retinoids

Question 7

A 50-year-old man presents with red, scaly patches on his scalp that bleed when scratched. This is indicative of which condition?

Accepted Answer

Psoriasis

Answer

Seborrheic dermatitis

Answer

Tinea capitis

Answer

Lichen planus

Question 8

A 40-year-old male presents with chronic, relapsing pustular eruptions on the palms and soles, along with a history of smoking. What is the most likely diagnosis?

Accepted Answer

Palmoplantar pustulosis

Answer

Pustular psoriasis

Answer

Dyshidrotic eczema

Answer

Contact dermatitis

Question 9

A 60-year-old woman presents with red, scaly patches on her arms that bleed easily when scratched. This is a classic sign of which condition?

Accepted Answer

Psoriasis

Answer

Seborrheic dermatitis

Answer

Actinic keratosis

Answer

Lichen planus

Question 10

Woronoff's ring is specifically associated with which skin condition?

Accepted Answer

Psoriasis

Answer

Lichen planus

Answer

Pityriasis rosea

Answer

Pemphigus

Psoriasis — MCQs

Psoriasis — MCQs

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