Autoimmune Skin Diseases — MCQs

Autoimmune Skin Diseases Indian Medical PG Practice Questions and MCQs

Question 11: The Pathergy test is positive in which of the following conditions?

A. Richter's disease
B. Behcet's disease (Correct Answer)
C. Ritter's disease
D. Erythema multiforme

Explanation: **Explanation:** **Behcet’s Disease (Correct Answer):** The Pathergy test is a hallmark diagnostic tool for Behcet’s disease. It represents a state of **cutaneous vascular hyper-reactivity** to minor trauma. The test is performed by pricking the skin (usually the forearm) with a sterile 20-gauge needle. A positive result is defined by the formation of a sterile erythematous papule or pustule (>2 mm) at the site within 24–48 hours. While highly specific for Behcet’s, its sensitivity varies geographically (highest in Silk Road populations). **Incorrect Options:** * **Richter’s Disease (Option A):** This refers to Richter’s Transformation, where a low-grade B-cell lymphoma (like CLL) transforms into an aggressive high-grade diffuse large B-cell lymphoma. It has no association with skin hyper-reactivity. * **Ritter’s Disease (Option C):** Also known as **Staphylococcal Scalded Skin Syndrome (SSSS)**, this is caused by exfoliative toxins from *Staphylococcus aureus*. It presents with widespread bullae and a positive Nikolsky sign, not pathergy. * **Erythema Multiforme (Option D):** A hypersensitivity reaction (often triggered by HSV or Mycoplasma) characterized by "target" or "iris" lesions. It does not involve pathergy. **Clinical Pearls for NEET-PG:** 1. **Other Pathergy-positive conditions:** Pyoderma Gangrenosum, Sweet Syndrome, and occasionally Crohn’s disease. 2. **Behcet’s Triad:** Recurrent oral ulcers (most common), genital ulcers (most specific), and uveitis. 3. **HLA Association:** Strongly associated with **HLA-B51**. 4. **Histopathology:** A positive pathergy test histologically shows a heavy neutrophilic infiltrate (leukocytoclastic vasculitis).

Question 12: A newborn presents with a bluish swelling over the upper eyelid. There is no lid edema or other eye involvement, and the swelling regressed spontaneously around one year of age. What is the most likely diagnosis?

A. Port wine stain
B. Capillary hemangioma
C. Salmon patch (Correct Answer)
D. Cirsoid aneurysm

Explanation: **Explanation:** The clinical presentation describes a **Salmon patch** (also known as Nevus Simplex), which is the most common vascular lesion in newborns. **1. Why Salmon Patch is Correct:** Salmon patches are capillary malformations (ectasias) that appear as flat, pink-to-red or bluish-red patches. They are typically found on the midline, most commonly the nape of the neck ("Stork bite"), the glabella, or the **upper eyelids** ("Angel’s kiss"). A hallmark feature is their **spontaneous regression**, usually within the first year of life, as seen in this case. **2. Why Other Options are Incorrect:** * **Port Wine Stain (Nevus Flammeus):** These are permanent capillary malformations. Unlike salmon patches, they are usually unilateral, do not cross the midline, grow proportionately with the child, and **never regress spontaneously**. * **Capillary Hemangioma (Strawberry Hemangioma):** These are true vascular tumors. While they can regress, they typically appear a few weeks after birth (not always present at birth), are **raised/lobulated** rather than flat, and undergo a rapid proliferative phase before slow involution over several years. * **Cirsoid Aneurysm:** This is an arteriovenous malformation (AVM) usually found on the scalp. It presents as a pulsatile, "bag of worms" mass with a thrill or bruit, and does not regress. **High-Yield Clinical Pearls for NEET-PG:** * **Salmon Patch:** Most common vascular lesion of infancy; midline location; disappears by age 1. * **Stork Bite vs. Angel’s Kiss:** Nape of neck lesions (Stork bite) often persist longer than facial lesions (Angel’s kiss). * **Port Wine Stain:** Associated with **Sturge-Weber Syndrome** (if in V1/V2 distribution) and **Klippel-Trenaunay Syndrome**. * **Kasabach-Merritt Syndrome:** A life-threatening consumptive coagulopathy associated with rapidly growing vascular tumors (Tufted angioma or Kaposiform hemangioendothelioma), *not* simple salmon patches.

Question 13: A patient with a systemic disease presents with Gottron's sign on their face and upper trunk. Which of the following pathological conditions is characterized by a positive Gottron's sign?

A. Systemic Lupus Erythematosus (SLE)
B. Polymyositis
C. Dermatomyositis (Correct Answer)
D. Acrodermatitis

Explanation: **Explanation:** **Dermatomyositis** is the correct answer. It is an idiopathic inflammatory myopathy characterized by proximal muscle weakness and distinctive cutaneous findings. **Gottron’s sign** refers to symmetric, erythematous to violaceous macules or patches found over the bony prominences, most commonly the interphalangeal and metacarpophalangeal joints, elbows, or knees. When these lesions become palpable and scaly, they are termed **Gottron’s papules**, which are considered pathognomonic for the disease. **Analysis of Incorrect Options:** * **Systemic Lupus Erythematosus (SLE):** While SLE presents with a malar (butterfly) rash, it typically **spares the nasolabial folds**, whereas the rash in Dermatomyositis often involves them. SLE does not feature Gottron’s sign. * **Polymyositis:** This condition shares the proximal muscle weakness seen in Dermatomyositis but is characterized by the **absence** of diagnostic cutaneous features like Gottron’s sign or the Heliotrope rash. * **Acrodermatitis:** This refers to inflammation of the skin of the extremities (e.g., Acrodermatitis enteropathica due to Zinc deficiency). It presents with periorificial and acral dermatitis, unrelated to the inflammatory myopathy of Dermatomyositis. **High-Yield Clinical Pearls for NEET-PG:** * **Heliotrope Rash:** Violaceous edema of the upper eyelids (another pathognomonic sign). * **Shawl Sign/V-sign:** Erythema over the upper back/shoulders or the anterior chest. * **Mechanic’s Hands:** Hyperkeratosis and fissuring of the lateral and palmar aspects of the fingers (associated with Anti-Jo-1 antibodies). * **Malignancy:** Dermatomyositis in adults carries a high association with internal malignancies (e.g., ovarian, lung, breast, GI). * **Antibodies:** Anti-Mi-2 is highly specific for Dermatomyositis; Anti-Jo-1 is associated with Antisynthetase Syndrome (interstitial lung disease).

Question 14: Which of the following statements regarding hereditary hemorrhagic telangiectasia is true?

A. Gastrointestinal bleeding is the major presenting feature.
B. It is associated with cerebral arteriovenous malformations. (Correct Answer)
C. Only mucosal involvement is present, and the skin is usually spared.
D. Estrogen is the first-line treatment.

Explanation: **Hereditary Hemorrhagic Telangiectasia (HHT)**, also known as **Osler-Weber-Rendu Syndrome**, is an autosomal dominant disorder characterized by multisystem vascular malformations. ### **Explanation of the Correct Option** **Option B is correct** because HHT involves the formation of direct connections between arteries and veins, bypassing the capillary bed. These **Arteriovenous Malformations (AVMs)** commonly occur in the **lungs (50%), liver (70%), and brain (10%)**. Cerebral AVMs are high-yield clinical features as they can lead to life-threatening complications like seizures or intracranial hemorrhage. ### **Analysis of Incorrect Options** * **Option A:** While GI bleeding occurs in about 25% of patients (usually later in life), **epistaxis (nosebleeds)** is the most common and earliest presenting feature, seen in over 90% of cases. * **Option C:** HHT involves both **mucosal and cutaneous** surfaces. Characteristic telangiectasias are typically found on the lips, tongue, face, and fingertips. * **Option D:** Estrogen was historically used to reduce bleeding, but it is **not first-line**. Management focuses on local measures (cautery, laser) and **Bevacizumab** (anti-VEGF antibody) for systemic involvement. ### **NEET-PG High-Yield Pearls** * **Curacao Criteria:** Used for diagnosis (Epistaxis, Telangiectasias, Visceral AVMs, and First-degree relative with HHT). 3/4 criteria confirm the diagnosis. * **Genetics:** Mutations in **ENG** (HHT1 - more pulmonary AVMs) or **ACVRL1** (HHT2 - more hepatic involvement). * **Complication:** Pulmonary AVMs can lead to paradoxical embolism, resulting in **brain abscesses** or strokes.

Question 15: The 'shawl sign' is a clinical finding associated with which of the following conditions?

A. Psoriasis
B. Dermatomyositis (Correct Answer)
C. Sunburn
D. Skin Cancer

Explanation: **Explanation:** **Dermatomyositis** is an idiopathic inflammatory myopathy characterized by proximal muscle weakness and distinctive cutaneous manifestations. The **Shawl sign** refers to a persistent, confluent, erythematous to violaceous macular rash involving the upper back, posterior neck, and shoulders (resembling the distribution of a shawl). This is a photosensitive eruption and is a classic diagnostic clue for the disease. **Analysis of Options:** * **Dermatomyositis (Correct):** Along with the Shawl sign, other pathognomonic features include **Gottron papules** (violaceous papules over bony prominences/knuckles), **Heliotrope rash** (periorbital violaceous edema), and the **V-sign** (rash on the anterior chest). * **Psoriasis:** Characterized by well-demarcated erythematous plaques with silvery-white scales, typically on extensors. It is associated with the Auspitz sign and Koebner phenomenon, not the Shawl sign. * **Sunburn:** While sunburn causes erythema in sun-exposed areas, the Shawl sign is a specific chronic inflammatory marker of dermatomyositis, often appearing even with minimal UV exposure and persisting longer than a simple burn. * **Skin Cancer:** While UV radiation is a risk factor for both, skin cancers (like BCC or SCC) present as localized nodules or non-healing ulcers rather than a diffuse, symmetrical "shawl-like" macular eruption. **High-Yield Clinical Pearls for NEET-PG:** * **Holster sign:** Erythema on the lateral aspect of the thighs (another specific sign of Dermatomyositis). * **Mechanic’s Hands:** Hyperkeratosis and fissuring of the palms/fingers; often associated with **Anti-Jo-1 antibodies** and interstitial lung disease. * **Malignancy Link:** Dermatomyositis in adults is a paraneoplastic syndrome; always screen for underlying visceral malignancies (e.g., ovarian, lung, or GI cancers).

Question 16: Scleredema is associated with which of the following conditions?

A. Progressive systemic sclerosis
B. Leprosy
C. Diabetes (Correct Answer)
D. Hypothyroidism

Explanation: **Explanation:** **Scleredema (Scleredema of Buschke)** is a rare sclerodermiform condition characterized by diffuse, non-pitting induration of the skin, primarily affecting the neck, shoulders, and upper back. **Why Diabetes is the Correct Answer:** Scleredema is classically associated with three clinical scenarios, the most common being **Diabetes Mellitus (Type 2)**. In diabetic patients (Scleredema Diabeticorum), the condition is typically seen in middle-aged, obese males with long-standing, poorly controlled glycemia. The underlying pathophysiology involves the non-enzymatic glycosylation of collagen and an increase in collagen synthesis by fibroblasts, leading to a thickened dermis with heavy deposits of acid mucopolysaccharides (mucin). **Analysis of Incorrect Options:** * **A. Progressive Systemic Sclerosis (PSS):** While both involve skin thickening, PSS (Scleroderma) typically starts distally (sclerodactyly), involves Raynaud’s phenomenon, and shows loss of skin appendages—features absent in Scleredema. * **B. Leprosy:** Leprosy presents with anesthetic patches, nerve thickening, or nodules (lepromas), not diffuse woody induration of the trunk. * **C. Hypothyroidism:** This is associated with **Generalized Myxedema**, where skin is dry, pale, and waxy due to dermal mucin, but it does not present with the specific "woody" induration of the upper back seen in Scleredema. **High-Yield Clinical Pearls for NEET-PG:** * **Three Types of Scleredema:** 1. **Type 1:** Follows an acute febrile illness (usually Streptococcal). 2. **Type 2:** Associated with Monoclonal Gammopathy (Multiple Myeloma). 3. **Type 3:** Associated with Diabetes Mellitus (most persistent form). * **Histopathology:** Significant dermal thickening with large collagen bundles separated by clear spaces containing **Hyaluronic acid** (Mucin). * **Clinical Sign:** The "Peau d’orange" appearance may be seen on the affected skin.

Question 17: Which of the following is an autoimmune disease?

A. Pemphigus Vulgaris (Correct Answer)
B. Psoriasis
C. Lichen Planus
D. Acne Vulgaris

Explanation: **Explanation:** **Pemphigus Vulgaris (Option A)** is the correct answer because it is a classic **Type II hypersensitivity** autoimmune bullous disorder. It is characterized by the production of IgG autoantibodies against **Desmoglein 3** (and sometimes Desmoglein 1), which are cadherin-type cell adhesion molecules. This leads to **acantholysis** (loss of keratinocyte cohesion), resulting in flaccid blisters on the skin and oral mucosa. **Why other options are incorrect:** * **Psoriasis (Option B):** While it involves an immune-mediated pathway (primarily Th17/IL-23 axis), it is classified as a **chronic inflammatory** disease rather than a primary autoimmune disease, as specific autoantigens are not the sole cause. * **Lichen Planus (Option C):** This is an **idiopathic inflammatory** condition. Although it involves a T-cell mediated cytotoxic reaction against basal keratinocytes, it is generally categorized as an inflammatory dermatosis. * **Acne Vulgaris (Option D):** This is a multifactorial disorder of the **pilosebaceous unit** involving follicular hyperkeratinization, sebum production, and *Cutibacterium acnes* colonization; it is not autoimmune. **NEET-PG High-Yield Pearls:** * **Nikolsky Sign:** Positive in Pemphigus Vulgaris (diagnostic hallmark). * **Tzanck Smear:** Shows **Acantholytic cells** (Tzanck cells/Row of tombstone appearance on histology). * **Immunofluorescence (DIF):** Shows a characteristic **"Fishnet" or "Lace-like"** pattern of IgG/C3 deposits in the intercellular spaces. * **Target Antigen:** Desmoglein 3 (Mucosal-dominant); Desmoglein 1 & 3 (Mucocutaneous).

Question 18: En-coup-de sabre is a form of?

A. Scleroderma (Correct Answer)
B. Syphilis
C. Lupus erythematosus
D. Alopecia

Explanation: **Explanation:** **En-coup-de-sabre** is a specific localized clinical variant of **Linear Scleroderma** (Morphea). The term is French for "stroke of the sword," describing its characteristic appearance: a linear, depressed, atrophic band typically occurring on the forehead or scalp. 1. **Why Scleroderma is correct:** Scleroderma is characterized by the hardening and thickening of the skin due to excessive collagen deposition. In the "En-coup-de-sabre" variant, this process leads to a vertical line of ivory-colored, sclerotic skin that may involve underlying muscle and bone, often resulting in permanent scarring alopecia in the affected scalp area. 2. **Why other options are incorrect:** * **Syphilis:** Primary syphilis presents with a painless chancre, and secondary syphilis with a generalized maculopapular rash (including palms/soles). It does not cause linear sclerotic bands. * **Lupus Erythematosus:** While Discoid Lupus (DLE) causes scarring alopecia, it typically presents as well-demarcated erythematous scaly plaques, not linear sword-like depressions. * **Alopecia:** While En-coup-de-sabre causes hair loss, it is a *cause* of cicatricial (scarring) alopecia, not a form of alopecia itself. **High-Yield Clinical Pearls for NEET-PG:** * **Parry-Romberg Syndrome:** This is a severe form of progressive facial hemiatrophy that is often associated with En-coup-de-sabre. * **Morphea vs. Systemic Sclerosis:** Unlike Systemic Sclerosis, Morphea (localized scleroderma) generally lacks Raynaud’s phenomenon and internal organ involvement. * **Histology:** Early lesions show thick collagen bundles and "loss of periappendageal fat." * **Complications:** Can be associated with neurological abnormalities (seizures or uveitis).

Question 19: A 25-year-old female presents with a history of fever and oral ulcers and has developed erythematous lesions on her face. What is the most likely diagnosis?

A. Systemic Lupus Erythematosus (SLE) (Correct Answer)
B. Dermatomyositis
C. Melasma
D. Rosacea

Explanation: **Explanation:** The clinical presentation of a young female with **fever, oral ulcers, and erythematous facial lesions** is a classic triad for **Systemic Lupus Erythematosus (SLE)**. 1. **Why SLE is correct:** SLE is a multisystem autoimmune disease predominantly affecting women of childbearing age. The facial lesions described typically represent the **Malar (Butterfly) rash**, which is characterized by erythema over the cheeks and nasal bridge, notably **sparing the nasolabial folds**. Oral ulcers (usually painless) and systemic symptoms like fever are part of the ACR/SLICC diagnostic criteria. 2. **Why other options are incorrect:** * **Dermatomyositis:** While it presents with facial rashes (Heliotrope rash), it typically involves the upper eyelids and is associated with proximal muscle weakness and Gottron papules. It does not usually present with oral ulcers. * **Melasma:** This presents as asymptomatic, hyperpigmented (brownish) macules and patches, usually triggered by UV exposure or hormones. It lacks systemic symptoms like fever or mucosal involvement. * **Rosacea:** This presents with erythema, telangiectasia, and papulopustules. Crucially, Rosacea **involves the nasolabial folds** and lacks systemic features like fever and oral ulcers. **High-Yield Clinical Pearls for NEET-PG:** * **Most specific antibody for SLE:** Anti-dsDNA and Anti-Smith. * **Most sensitive screening test:** ANA (Indirect Immunofluorescence). * **Lupus Band Test:** Direct Immunofluorescence (DIF) shows a linear band of IgG and C3 at the dermo-epidermal junction in both involved and uninvolved skin. * **Drug-induced Lupus:** Most common drug is Procainamide; most common antibody is **Anti-Histone**.

Question 20: Histological appearance of scleroderma includes all except?

A. Extensive fibrosis of upper 1/3 of the dermis (Correct Answer)
B. Decreased adnexal structures
C. Homogenization of collagen
D. Increased dermal thickness

Explanation: **Explanation:** The hallmark of **Scleroderma (Systemic Sclerosis)** is the excessive deposition of collagen throughout the dermis. However, the fibrosis is not limited to the upper 1/3; instead, it typically involves the **entire thickness of the dermis** and often extends into the subcutaneous fat. * **Why Option A is the correct answer:** In scleroderma, fibrosis is **pan-dermal**. The collagen bundles become thick, packed, and oriented parallel to the epidermis. Restricting the description to only the "upper 1/3" is histologically inaccurate as the disease process characteristically involves the deep dermis and leads to the loss of the dermo-hypodermal interface. * **Why other options are incorrect:** * **Decreased adnexal structures (B):** As collagen bundles expand and pack tightly, they "choke" or replace normal skin structures. This leads to the atrophy and eventual disappearance of hair follicles and sweat glands. * **Homogenization of collagen (C):** Under the microscope, the collagen bundles lose their distinct outlines and appear as a solid, eosinophilic (pink), glassy mass. * **Increased dermal thickness (D):** The massive deposition of Type I and Type III collagen significantly increases the overall depth of the dermal layer, which clinically manifests as skin tightening and induration. **NEET-PG High-Yield Pearls:** 1. **Square-off Sign:** On biopsy, the specimen often appears rectangular or "squared-off" because the tissue is so rigid it does not curl. 2. **Entrapment of Eccrine Glands:** A classic sign where sweat glands appear "trapped" in the middle of dense dermal collagen rather than sitting at the dermo-hypodermal junction. 3. **CD34+ Fibroblasts:** There is a characteristic **loss** of CD34+ dendritic interstitial cells in the affected dermis. 4. **Clinical Triad:** Vascular injury (Raynaud’s), Autoimmunity (ANA, Scl-70, Anti-centromere), and Progressive Fibrosis.

Practice by Chapter

Lupus Erythematosus: Cutaneous Forms

Practice Questions

Lupus Erythematosus: Systemic with Skin Manifestations

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Dermatomyositis

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Scleroderma and Morphea

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Mixed Connective Tissue Disease

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Sjögren's Syndrome: Cutaneous Manifestations

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Relapsing Polychondritis

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Autoimmune Thyroid Disease and the Skin

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Immunobullous Disorders

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Vasculitis

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Diagnostic Methods in Autoimmune Dermatoses

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Management of Autoimmune Skin Diseases

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