Autoimmune Skin Diseases Practice Questions

Q: A 35-year-old woman presents with an erythematous, scaly plaque on her scalp accompanied by hair loss. A biopsy reveals lymphocytic infiltration around the hair follicles. What is the most likely diagnosis?

Discoid lupus erythematosus. ***Discoid lupus erythematosus*** - This condition is characterized by **erythematous, scaly plaques** with associated **permanent hair loss (scarring alopecia)** on the scalp, often forming **atrophic scars**. - Histologically, it presents with a **lymphocytic infiltrate** around hair follicles and the **dermal-epidermal junction**, along with **follicular plugging** and **basal layer degeneration**. *Alopecia areata* - This is a non-scarring form of hair loss, meaning the hair follicles are not permanently destroyed, and hair can regrow. - While it involves lymphocytic infiltration, it typically presents as **smooth, well-demarcated patches of hair loss** without significant erythema or scaling of the skin. *Tinea capitis* - This is a **fungal infection** that causes scaly patches and hair loss, but a biopsy would reveal **fungal elements** within the hair shafts and follicles, not primarily a lymphocytic infiltrate. - Often associated with **broken hairs** and sometimes **pustules**, and can be diagnosed with a **KOH prep** or fungal culture. *Psoriasis* - Scalp psoriasis presents as **thick, silvery scales** on an erythematous base, often with well-demarcated plaques. - While it can cause hair shedding due to inflammation, it does not typically lead to scarring alopecia or the specific perifollicular lymphocytic infiltrate seen in lupus.

Q: A patient with systemic lupus erythematosus develops a rash after sun exposure. The rash is erythematous with a butterfly distribution. What is the name of this rash?

Malar rash. ***Malar rash*** - This rash is characteristic of **systemic lupus erythematosus (SLE)** and presents as an **erythematous** eruption in a **butterfly distribution** over the cheeks and bridge of the nose. - It is often **photosensitive**, meaning it is triggered or exacerbated by sun exposure, as described in the patient's presentation. *Discoid rash* - While also associated with lupus (particularly discoid lupus erythematosus), a **discoid rash** presents as chronic, scarring lesions with **follicular plugging** and **atrophy**, which is not described as a **butterfly distribution**. - Discoid lesions are typically sharply demarcated and can lead to permanent changes in skin texture and pigmentation. *Photosensitive rash* - This is a general term describing any rash that appears or worsens with **sun exposure**. While the malar rash is photosensitive, this option is too broad and does not specify the characteristic appearance. - Many skin conditions, not just lupus-related rashes, can be photosensitive. *Livedo reticularis* - This is a vascular mottled rash characterized by a **net-like** or **lacy pattern** caused by constriction of small blood vessels, often due to abnormalities in blood flow. - It is not typically described as a **butterfly distribution** and is not the classic rash associated with acute lupus flares after sun exposure.

Q: A 65-year-old woman presents with bullous lesions on her arms and legs that rupture easily, and Nikolsky's sign is positive. What is the most likely diagnosis?

Pemphigus vulgaris. ***Pemphigus vulgaris*** - **Pemphigus vulgaris** is characterized by flaccid bullae that rupture easily, leading to erosions, and a **positive Nikolsky's sign**. - This condition involves autoantibodies against **desmoglein 1 and 3**, leading to acantholysis within the epidermis. *Bullous pemphigoid* - This condition is characterized by **tense bullae** that do not rupture easily and a **negative Nikolsky's sign**. - Autoantibodies target **hemidesmosomes**, resulting in subepidermal blistering rather than intraepidermal. *Erythema multiforme* - Typically presents with **targetoid lesions** (central blister or crust with surrounding erythema) and is often precipitated by infections or drugs. - While blistering can occur, it's not the primary feature and Nikolsky's sign is usually negative. *Dermatitis herpetiformis* - Presents with intensely **itchy papulovesicles** and is strongly associated with **celiac disease**. - The lesions are typically small, grouped vesicles, not large, flaccid bullae, and Nikolsky's sign is negative.

Q: A 60-year-old woman with a history of systemic lupus erythematosus presents with a persistent rash on her face. Examination reveals well-demarcated, coin-shaped erythematous plaques with scaling and central atrophic areas. What is the most likely diagnosis?

Discoid lupus erythematosus. ***Discoid lupus erythematosus*** - This patient's history of **systemic lupus erythematosus (SLE)** and the description of a **discoid rash** with erythematous, scaly, and atrophic areas on the face are classic findings for discoid lupus erythematosus (DLE). - DLE is a **chronic cutaneous form of lupus** that can occur in patients with SLE or as an isolated condition, characterized by scarring and pigmentary changes. *Psoriasis* - Psoriasis typically presents as **well-demarcated, erythematous plaques** with silvery scales, often on extensor surfaces like elbows and knees, distinct from the described rash. - While psoriasis can affect the face, the presence of **atrophy** and history of SLE make DLE a far more likely diagnosis. *Rosacea* - Rosacea often involves **facial erythema, telangiectasias, papules, and pustules**, primarily affecting the central face, but does not present with the same scaly, atrophic, and scarring lesions characteristic of DLE. - It lacks the **discoid morphology** and is not typically associated with SLE. *Seborrheic dermatitis* - Seborrheic dermatitis manifests as **greasy, yellowish scales on an erythematous base**, commonly affecting areas rich in sebaceous glands such as the scalp, eyebrows, and nasolabial folds. - The lesions usually do not lead to **atrophy or scarring**, which are key features of the described rash.

Q: Which of the following is not a feature of dermatomyositis?

Groove sign. ***Groove sign*** - The **Groove sign** (referring to prominent **longitudinal ridging and grooves** in the nails) is NOT a typical feature of dermatomyositis. - This nail manifestation is characteristically seen in **lichen planus** and other conditions, but not in classic dermatomyositis. - In dermatomyositis, nail changes include **periungual telangiectasias**, **ragged cuticles**, and **nail fold capillary changes**, but not prominent nail grooves. *'V' sign* - The **'V' sign** is a characteristic cutaneous finding in dermatomyositis, presenting as **photodistributed erythema** on the anterior neck and upper chest in a 'V' shape. - This distribution corresponds to sun-exposed areas and is a common manifestation of the disease. *Holster sign* - The **Holster sign** refers to **poikilodermatous changes** located on the lateral aspects of the thighs, resembling the area where a holster would be worn. - It is a specific cutaneous manifestation of dermatomyositis, often indicating chronic photodamage in the disease. *Poikiloderma* - **Poikiloderma** is a combination of **atrophy**, **telangiectasias**, and **dyspigmentation** (both hypo- and hyperpigmentation) of the skin. - Poikiloderma is a prominent feature in dermatomyositis, especially in photodistributed areas like the neck (V-sign), upper back (Shawl sign), and lateral thighs (Holster sign).

Q: Which of the following diseases is closely related to enteropathy?

Dermatitis herpetiformis. ***Dermatitis herpetiformis*** - This condition is strongly associated with **celiac disease** (gluten-sensitive enteropathy), where **IgA deposits** are found in the skin and small intestine. - Patients typically present with intensely pruritic, polymorphic skin lesions, and often have **villous atrophy** of the small intestine, requiring a **gluten-free diet**. *Linear IgA disease* - Characterized by **linear IgA deposits** along the basement membrane zone, but it is not typically associated with enteropathy. - The disease can be **idiopathic** or **drug-induced**, commonly seen with **vancomycin**. *Pemphigus foliaceus* - An autoimmune blistering disease where **antibodies target desmoglein 1** in the superficial epidermis, leading to superficial blisters and erosions. - It is not associated with **gastrointestinal pathology** or enteropathy. *Erythema multiforme* - This is an acute, self-limited, and often recurrent mucocutaneous syndrome characterized by target lesions, often triggered by **infections (e.g., HSV)** or **drugs**. - It is an immune-mediated reaction and does not have a primary association with **enteropathy**.

Q: Which of the following statements about lichen planus is true?

Oral lichen planus has a small risk of malignancy.. ***Oral lichen planus has a small risk of malignancy.*** - **Oral lichen planus (OLP)** is classified by WHO as an **oral potentially malignant disorder (OPMD)** with a documented malignant transformation rate of approximately **0.4-1.5%**. - The risk is highest in **erosive and atrophic forms**, particularly affecting the tongue and buccal mucosa. - **Regular monitoring** with biopsy of suspicious lesions is recommended due to this small but clinically significant **risk of squamous cell carcinoma**. - Among all the options presented, this represents the most clinically important statement requiring awareness in medical practice. *Lichen planus can heal spontaneously.* - This statement is **medically accurate** - cutaneous lichen planus can resolve spontaneously in 50-75% of cases within 1-2 years. - However, **oral and erosive forms** tend to be chronic and persistent, often requiring treatment. - While true, this is less clinically significant than recognizing the malignancy risk of oral lesions. *Lichen planus can cause scarring alopecia.* - This statement is also **medically accurate** - **lichen planopilaris (LPP)** is a follicular variant that causes **permanent scarring alopecia**. - LPP leads to irreversible hair loss due to follicular destruction and scarring. - However, this affects only the follicular variant, not classic lichen planus, making it a more limited statement. *Ocular pterygium is a feature of lichen planus.* - This is **incorrect** - **ocular pterygium** is a conjunctival growth extending onto the cornea, typically caused by **UV exposure**, not lichen planus. - Lichen planus does affect nails (causing thinning, ridging, pterygium formation in nails, or nail loss) but does **not** cause ocular pterygium.

Q: What condition is associated with Gottron's sign?

Dermatomyositis. ***Dermatomyositis*** - **Gottron's sign** is a pathognomonic rash associated with **dermatomyositis**, characterized by **erythematous, scaly papules** over the dorsal aspect of the interphalangeal joints. - This condition is an **inflammatory myopathy** affecting both the skin and muscles, leading to muscle weakness and characteristic skin manifestations. *Herpes infection* - Herpes infections cause **vesicular lesions** often seen in clusters, such as **cold sores** (herpes labialis) or **shingles** (herpes zoster), and do not present as Gottron's sign. - The rash is typically painful and burning, unlike the papular rash of Gottron's sign. *Bacterial infection* - Bacterial infections can cause a wide variety of skin lesions, including **abscesses**, **cellulitis**, or **pustules**, but these are distinct from the specific morphology of Gottron's sign. - They are usually accompanied by signs of local inflammation like warmth, swelling, and tenderness, and often respond to antibiotics. *None of the options.* - This option is incorrect because **Gottron's sign** is definitively associated with **dermatomyositis**, which is listed as an option. - There is a clear and well-documented medical condition directly corresponding to the described skin manifestation.

Q: Flaccid bullae with mucosal involvement and intraepidermal acantholysis are characteristic of which condition?

Pemphigus vulgaris. ***Pemphigus vulgaris*** - This autoimmune blistering disease is characterized by **flaccid bullae**, **mucosal involvement**, and **intraepidermal acantholysis**, specifically targeting **desmoglein 3** and often desmoglein 1. - The blistering occurs within the epidermis due to loss of cell-to-cell adhesion, leading to a positive **Nikolsky's sign**. *Pemphigus foliaceus* - This condition involves **superficial blistering** (subcorneal acantholysis) and typically presents with **crusted erosions** rather than intact flaccid bullae, often without mucosal involvement. - It primarily targets **desmoglein 1**, leading to blistering in the more superficial layers of the epidermis. *Psoriasis* - This is a chronic inflammatory skin condition characterized by **erythematous plaques** with silvery scales, often on extensor surfaces. - It involves **epidermal hyperplasia** and inflammation, not blistering due to acantholysis. *Vitiligo* - Vitiligo is a **pigmentary disorder** characterized by **depigmented patches** of skin caused by the destruction of melanocytes. - It does not involve bullae, acantholysis, or any form of blistering.

Q: What is the antigen defect associated with Pemphigus Vulgaris?

Desmoglein-3. ***Desmoglein-3*** - Pemphigus vulgaris is characterized by **autoantibodies** primarily targeting **desmoglein-3**, a component of **desmosomes**. - This autoimmune attack leads to **acantholysis** (loss of cell adhesion) within the deep epidermis, resulting in **flaccid blisters** that rupture easily. *Desmoglein-1* - Autoantibodies against **desmoglein-1** are primarily associated with **Pemphigus Foliaceus**, which causes more superficial blistering. - While Dsg1 antibodies can be present in Pemphigus vulgaris, Dsg3 antibodies are the **main culprits** responsible for the characteristic oral lesions and widespread deep epidermal blistering. *Desmocollin-3* - **Desmocollins** are another family of **cadherin proteins** found in desmosomes, but they are not the primary target in Pemphigus vulgaris. - Antibodies against desmocollins are less common and typically do not cause the classic clinical picture of pemphigus. *Desmocollin-2* - **Desmocollin-2** is found in **desmosomes**, but it is not the main target of autoantibodies in Pemphigus vulgaris. - The disease is specifically characterized by the disruption of cell-to-cell adhesion mediated by desmogleins.

Question 1

A 35-year-old woman presents with an erythematous, scaly plaque on her scalp accompanied by hair loss. A biopsy reveals lymphocytic infiltration around the hair follicles. What is the most likely diagnosis?

Accepted Answer

Discoid lupus erythematosus

Answer

Alopecia areata

Answer

Tinea capitis

Answer

Psoriasis

Question 2

A patient with systemic lupus erythematosus develops a rash after sun exposure. The rash is erythematous with a butterfly distribution. What is the name of this rash?

Accepted Answer

Malar rash

Answer

Discoid rash

Answer

Photosensitive rash

Answer

Livedo reticularis

Question 3

A 65-year-old woman presents with bullous lesions on her arms and legs that rupture easily, and Nikolsky's sign is positive. What is the most likely diagnosis?

Accepted Answer

Pemphigus vulgaris

Answer

Bullous pemphigoid

Answer

Erythema multiforme

Answer

Dermatitis herpetiformis

Question 4

A 60-year-old woman with a history of systemic lupus erythematosus presents with a persistent rash on her face. Examination reveals well-demarcated, coin-shaped erythematous plaques with scaling and central atrophic areas. What is the most likely diagnosis?

Accepted Answer

Discoid lupus erythematosus

Answer

Psoriasis

Answer

Rosacea

Answer

Seborrheic dermatitis

Question 5

Which of the following is not a feature of dermatomyositis?

Accepted Answer

Groove sign

Answer

Poikiloderma

Answer

'V' sign

Answer

Holster sign

Question 6

Which of the following diseases is closely related to enteropathy?

Accepted Answer

Dermatitis herpetiformis

Answer

Linear IgA disease

Answer

Pemphigus foliaceus

Answer

Erythema multiforme

Question 7

Which of the following statements about lichen planus is true?

Accepted Answer

Oral lichen planus has a small risk of malignancy.

Answer

Lichen planus can heal spontaneously.

Answer

Lichen planus can cause scarring alopecia.

Answer

Ocular pterygium is a feature of lichen planus.

Question 8

What condition is associated with Gottron's sign?

Accepted Answer

Dermatomyositis

Answer

None of the options.

Answer

Herpes infection

Answer

Bacterial infection

Question 9

Flaccid bullae with mucosal involvement and intraepidermal acantholysis are characteristic of which condition?

Accepted Answer

Pemphigus vulgaris

Answer

Pemphigus foliaceus

Answer

Psoriasis

Answer

Vitiligo

Question 10

What is the antigen defect associated with Pemphigus Vulgaris?

Accepted Answer

Desmoglein-3

Answer

Desmoglein-1

Answer

Desmocollin-3

Answer

Desmocollin-2

Autoimmune Skin Diseases — MCQs

Autoimmune Skin Diseases — MCQs

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