Autoimmune Skin Diseases — MCQs

Autoimmune Skin Diseases Indian Medical PG Practice Questions and MCQs

Question 61: Immunofluorescence is seen at the basement membrane as a patchy distribution in which of the following conditions?

A. Lichen Planus
B. Pemphigus
C. Pemphigoid (Correct Answer)
D. Lupus erythematosus

Explanation: **Explanation:** The question focuses on the Direct Immunofluorescence (DIF) patterns of autoimmune and inflammatory skin diseases. **Why Pemphigoid is Correct:** In **Bullous Pemphigoid**, autoantibodies (IgG and C3) target the hemidesmosomes (BP180 and BP230) at the dermo-epidermal junction. On DIF, this manifests as a **linear, continuous, or patchy/shaggy deposition** of IgG and C3 along the **basement membrane zone (BMZ)**. The term "patchy" or "shaggy" is often used to describe the irregular intensity of the linear band seen in subepidermal blistering diseases. **Analysis of Incorrect Options:** * **Lichen Planus:** DIF typically shows **shaggy** deposits of **fibrinogen** along the BMZ and globular deposits of IgM (Cytoid/Civatte bodies) in the papillary dermis. It is not primarily characterized by patchy IgG at the BMZ. * **Pemphigus:** This is an intraepidermal disease. DIF shows a characteristic **"fishnet" or "lace-like" pattern** of IgG and C3 in the intercellular spaces of the epidermis, not at the basement membrane. * **Lupus Erythematosus (SLE/DLE):** While LE shows a "Lupus Band" (granular IgG/IgM at the BMZ), it is classically described as a **continuous granular band**, rather than the patchy distribution characteristic of the pemphigoid group. **NEET-PG High-Yield Pearls:** * **Bullous Pemphigoid:** Linear BMZ pattern; Salt-split skin study shows localization to the **roof** of the blister. * **Epidermolysis Bullosa Acquisita (EBA):** Also shows linear BMZ pattern, but localization is to the **floor** of the blister. * **Dermatitis Herpetiformis:** Characterized by **granular IgA** deposits at the tips of dermal papillae. * **Pemphigus Vulgaris:** IgG targets **Desmoglein 3** (mucosal) and **Desmoglein 1** (skin).

Question 62: The Band test is indicated in which of the following conditions?

A. Rheumatoid arthritis
B. Systemic lupus erythematosus (Correct Answer)
C. Scleroderma
D. Polyarteritis nodosa

Explanation: The **Lupus Band Test (LBT)** is a direct immunofluorescence (DIF) technique used to detect the deposition of immunoglobulins (primarily IgG and IgM) and complement (C3) at the dermo-epidermal junction (DEJ). ### **Why Systemic Lupus Erythematosus (SLE) is Correct** In SLE, immune complexes deposit at the DEJ, appearing as a continuous or granular "band" under a fluorescence microscope. The test is highly specific for Lupus: * **Lesional LBT:** Performed on skin with a rash. It is positive in both Discoid LE (DLE) and SLE. * **Non-lesional LBT:** Performed on clinically normal skin. A positive result here is highly suggestive of **Systemic Lupus Erythematosus (SLE)** and helps differentiate it from localized cutaneous forms. ### **Why Other Options are Incorrect** * **A. Rheumatoid Arthritis:** While an autoimmune disease, it primarily affects synovium. It does not typically show specific immunoglobulin banding at the dermo-epidermal junction. * **C. Scleroderma:** Characterized by excessive collagen deposition and fibrosis. Diagnosis is clinical and supported by specific antibodies (Anti-Scl70, Anti-centromere), not the Band test. * **D. Polyarteritis Nodosa:** A systemic necrotizing vasculitis of medium and small-sized arteries. Diagnosis requires biopsy showing transmural inflammation of arteries, not DEJ immunofluorescence. ### **High-Yield Clinical Pearls for NEET-PG** * **Sun-exposed vs. Sun-protected skin:** A positive LBT in **sun-protected** normal skin (e.g., inner forearm) is a strong indicator of systemic involvement and high disease activity in SLE. * **False Positives:** Can occur in sun-damaged skin (actinic keratosis) or occasionally in Rosacea. * **Most common Ig:** **IgM** is the most frequently detected antibody in the Lupus Band Test.

Question 63: Which of the following is not seen in Behçet's syndrome?

A. Genital ulcers
B. Uveitis
C. Oral ulcers
D. Pyoderma gangrenosum (Correct Answer)

Explanation: **Explanation:** Behçet’s syndrome is a chronic, multisystem inflammatory disorder characterized by systemic vasculitis. The diagnosis is primarily clinical, based on the **International Study Group (ISG) criteria**, which require the presence of recurrent oral ulcers plus any two of the following: recurrent genital ulcers, eye lesions, skin lesions, or a positive pathergy test. **Why Pyoderma Gangrenosum (PG) is the correct answer:** While Behçet’s syndrome is associated with various cutaneous manifestations, **Pyoderma gangrenosum** is not a characteristic feature. PG is a neutrophilic dermatosis typically associated with Inflammatory Bowel Disease (IBD), Rheumatoid Arthritis, and hematological malignancies. In Behçet’s, the classic skin lesions are **erythema nodosum-like lesions**, pseudofolliculitis, acneiform nodules, and palpable purpura. **Analysis of incorrect options:** * **Oral Ulcers (Option C):** These are the hallmark and usually the first sign of the disease. They are painful, recurrent, and must occur at least three times in a 12-month period for diagnosis. * **Genital Ulcers (Option A):** These are highly specific for Behçet’s. Unlike oral ulcers, they are deeper and often heal with scarring. * **Uveitis (Option B):** Ocular involvement occurs in about 70% of patients. **Bilateral posterior uveitis** is the most common serious complication and can lead to blindness. **Clinical Pearls for NEET-PG:** * **Pathergy Test:** A unique diagnostic feature where a sterile pustule forms 24–48 hours after a skin prick with a 20-gauge needle. * **HLA Association:** Strongly linked with **HLA-B51**. * **Hypopyon:** The presence of inflammatory cells in the anterior chamber of the eye (sterile pus) is a classic ocular finding. * **Magic Syndrome:** A rare variant showing features of both Behçet’s and Relapsing Polychondritis (Mouth And Genital Ulcers with Inflamed Cartilage).

Question 64: Adenoma sebaceum and shagreen patches are seen in which of the following conditions?

A. Neurofibromatosis I
B. Tuberous sclerosis (Correct Answer)
C. Von Hippel-Lindau disease
D. Li-Fraumeni syndrome

Explanation: **Explanation:** **Tuberous Sclerosis Complex (TSC)**, also known as Bourneville’s disease, is an autosomal dominant neurocutaneous syndrome caused by mutations in the **TSC1 (Hamartin)** or **TSC2 (Tuberin)** genes. The classic clinical triad (Vogt’s triad) includes seizures, mental retardation, and adenoma sebaceum. * **Adenoma Sebaceum:** Despite the name, these are actually **facial angiofibromas**. They typically appear as reddish papules in a butterfly distribution over the nose and cheeks. * **Shagreen Patches:** These are connective tissue nevi (collagenomas) usually found in the lumbosacral region, presenting as firm, leathery, "orange-peel" textured plaques. **Analysis of Incorrect Options:** * **Neurofibromatosis I (NF-1):** Characterized by Lisch nodules, Café-au-lait spots (6 or more), and neurofibromas. It does not feature shagreen patches. * **Von Hippel-Lindau (VHL):** Associated with hemangioblastomas of the retina and cerebellum, and renal cell carcinoma. It lacks the specific cutaneous markers of TSC. * **Li-Fraumeni Syndrome:** A cancer predisposition syndrome caused by p53 mutations, leading to various internal malignancies (sarcomas, breast cancer) rather than specific hamartomatous skin lesions. **High-Yield Clinical Pearls for NEET-PG:** * **Ash-leaf spots:** Hypopigmented macules; often the *earliest* sign of TSC. * **Koenen tumors:** Periungual fibromas appearing around the nails. * **Confetti lesions:** Multiple tiny hypopigmented macules on the limbs. * **Systemic findings:** Cardiac rhabdomyomas (often regress), Renal Angiomyolipomas (AML), and Giant Cell Astrocytomas (SEGA).

Question 65: What is the commonest cutaneous eruption in Systemic Lupus Erythematosus?

A. Palmar erythema
B. Discoid lesions
C. Erythema of light-exposed areas (Correct Answer)
D. Diffuse morbilliform erythema

Explanation: **Explanation:** Systemic Lupus Erythematosus (SLE) is a multisystem autoimmune disease characterized by a wide array of dermatological manifestations. **Why Option C is Correct:** The most common cutaneous eruption in SLE is **photosensitivity**, manifesting as **erythema of light-exposed areas**. This includes the classic **malar rash** (butterfly rash), which is a fixed erythema over the cheeks and bridge of the nose, typically sparing the nasolabial folds. Photosensitivity is reported in approximately 70-90% of SLE patients. The underlying mechanism involves UV-induced apoptosis of keratinocytes, leading to the exposure of nuclear antigens (like Ro/SSA) to the immune system, triggering an inflammatory response. **Analysis of Incorrect Options:** * **A. Palmar erythema:** While it can occur in SLE (often as part of vasculitis or associated pregnancy/liver issues), it is non-specific and much less common than photosensitivity. * **B. Discoid lesions:** These are the hallmark of Chronic Cutaneous Lupus Erythematosus (CCLE). While 10-15% of SLE patients may have discoid lesions, they are not the *most common* eruption in the systemic form. * **D. Diffuse morbilliform erythema:** This is a non-specific maculopapular rash often seen in drug eruptions or viral exanthems. While SLE can present with a generalized maculopapular rash, it is less frequent than localized malar/photosensitive erythema. **High-Yield Clinical Pearls for NEET-PG:** * **Malar Rash:** Sparing of the **nasolabial folds** is a key clinical differentiator from seborrheic dermatitis or rosacea. * **Lupus Hair:** Characterized by thin, frizzy hair at the frontal hairline; a common sign of systemic activity. * **Most Specific Test:** Anti-dsDNA and Anti-Smith antibodies. * **Most Sensitive Test:** ANA (Antinuclear Antibody). * **Histopathology:** The "Lupus Band Test" shows linear IgG/C3 deposits at the dermo-epidermal junction.

Question 66: What is the best serological test for subacute cutaneous lupus erythematosus?

A. dsDNA antibodies
B. Anti-Jo-1 antibody
C. Anti-Ro/SSA antibodies (Correct Answer)
D. Anti-histone antibodies

Explanation: **Explanation:** **Subacute Cutaneous Lupus Erythematosus (SCLE)** is a distinct subset of lupus erythematosus characterized by photosensitive, non-scarring annular or psoriasiform skin lesions. **Why Anti-Ro/SSA is the correct answer:** The hallmark of SCLE is its strong association with **Anti-Ro/SSA antibodies** (present in ~75–90% of cases) and, to a lesser extent, Anti-La/SSB antibodies. These antibodies are pathogenic in inducing photosensitivity. SCLE is also the classic presentation of **Drug-Induced SCLE** (commonly caused by HCTZ, Terbinafine, and Calcium Channel Blockers) and is the primary antibody profile seen in **Neonatal Lupus**. **Analysis of Incorrect Options:** * **A. dsDNA antibodies:** Highly specific for **Systemic Lupus Erythematosus (SLE)** and correlate with disease activity and lupus nephritis, but they are typically negative in pure SCLE. * **B. Anti-Jo-1 antibody:** The most common anti-synthetase antibody associated with **Dermatomyositis**, characterized by "Mechanic’s hands," interstitial lung disease, and arthritis. * **D. Anti-histone antibodies:** The classic marker for **Drug-Induced SLE** (e.g., caused by Hydralazine, Procainamide, Isoniazid). Note: Drug-induced *SLE* has anti-histone antibodies, but drug-induced *SCLE* has anti-Ro antibodies. **High-Yield Clinical Pearls for NEET-PG:** * **SCLE Morphology:** Annular/polycyclic or Psoriasiform lesions; heals **without scarring** (unlike Discoid Lupus). * **HLA Association:** Strongly linked to **HLA-DR3**. * **Neonatal Lupus:** Caused by transplacental transfer of Anti-Ro/SSA; most common complication is **congenital heart block**. * **ANA:** Usually positive in SCLE, but Anti-Ro is the most specific serological marker for this subtype.

Question 67: Gottron's papules or sign is seen in which of the following conditions?

A. Dermatomyositis (Correct Answer)
B. Multiple myeloma
C. Acute myeloid leukemia
D. Psoriasis

Explanation: **Explanation:** **Dermatomyositis** is an idiopathic inflammatory myopathy characterized by proximal muscle weakness and distinctive cutaneous findings. **Gottron’s papules** are considered a pathognomonic (highly specific) feature of this condition. They are erythematous to violaceous, flat-topped papules found over the dorsal aspects of the interphalangeal and metacarpophalangeal joints. **Gottron’s sign** refers to similar symmetric violaceous erythema (with or without edema) over the elbows, knees, or medial malleoli. **Analysis of Incorrect Options:** * **Multiple Myeloma:** This plasma cell dyscrasia is associated with skin findings like systemic amyloidosis (e.g., pinch purpura, macroglossia) but not Gottron’s papules. * **Acute Myeloid Leukemia (AML):** Cutaneous manifestations of AML include Leukemia Cutis (nodules/plaques) or Sweet Syndrome (neutrophilic dermatosis), which are clinically distinct from the papules seen in dermatomyositis. * **Psoriasis:** While psoriasis presents with erythematous plaques, they typically feature silvery-white scales and are found on extensor surfaces (elbows/knees) rather than specifically over the small joints of the hands. **High-Yield Clinical Pearls for NEET-PG:** * **Heliotrope Rash:** Violaceous eruption on the upper eyelids with periorbital edema (another pathognomonic sign). * **Shawl Sign & V-Sign:** Erythema over the upper back/shoulders and the anterior chest, respectively. * **Mechanic’s Hands:** Hyperkeratosis and fissuring of the palmar and lateral surfaces of the fingers (associated with Anti-Jo-1 antibodies). * **Malignancy Risk:** Dermatomyositis in adults is frequently a **paraneoplastic syndrome**; always screen for underlying internal malignancies (e.g., ovarian, lung, or GI cancers).

Question 68: Which of the following is NOT typically seen in dermatomyositis?

A. Salmon patch (Correct Answer)
B. Gottron's papules
C. Perioral telangiectasia
D. Mechanic's finger

Explanation: The correct answer is **A. Salmon patch**. ### **Explanation** **Salmon patch** (Nevus simplex) is a common congenital capillary malformation (vascular birthmark) typically found on the nape of the neck (stork bite) or the forehead/eyelids (angel kiss). It is a benign, developmental condition and has no clinical association with **Dermatomyositis**, which is an autoimmune inflammatory myopathy. ### **Analysis of Other Options** * **B. Gottron’s papules:** These are considered **pathognomonic** for dermatomyositis. They are violaceous, lichenoid papules found over the dorsal aspects of the interphalangeal and metacarpophalangeal joints. * **C. Periungual/Perioral telangiectasia:** Dilated capillary loops at the nail folds (periungual) or around the mouth are classic vascular signs of dermatomyositis, reflecting the underlying microangiopathy. * **D. Mechanic’s hands/fingers:** This refers to hyperkeratotic, fissured, "dirty-appearing" scaling on the lateral and palmar aspects of the fingers. It is highly associated with **Anti-synthetase syndrome** (a subset of dermatomyositis) and interstitial lung disease (ILD). ### **High-Yield Clinical Pearls for NEET-PG** * **Heliotrope rash:** Violaceous edema of the upper eyelids (another pathognomonic sign). * **Shawl sign & V-sign:** Poikiloderma (atrophy, telangiectasia, pigmentation) over the upper back/shoulders and the anterior chest, respectively. * **Holster sign:** Poikiloderma on the lateral aspect of the thighs. * **Malignancy:** Dermatomyositis in adults carries a high risk of internal malignancy (e.g., ovarian, lung, breast, GI). * **Key Antibody:** **Anti-Mi-2** is highly specific for dermatomyositis; **Anti-Jo-1** is associated with Mechanic's hands and ILD.

Question 69: Chloroquine is used in the treatment of which of the following dermatological conditions?

A. Discoid Lupus Erythematosus (DLE) (Correct Answer)
B. Pemphigus
C. Psoriasis
D. Nummular eczema

Explanation: **Explanation:** **Chloroquine** and its derivative, Hydroxychloroquine (HCQ), are **antimalarial agents** that have become a cornerstone in the management of various connective tissue disorders. **1. Why DLE is the Correct Answer:** Discoid Lupus Erythematosus (DLE) is a chronic, scarring form of cutaneous lupus. Antimalarials are the **first-line systemic treatment** for DLE. They work by inhibiting antigen presentation, reducing the production of pro-inflammatory cytokines (like IFN-alpha), and protecting the skin from UV-induced damage by stabilizing lysosomal membranes. They are particularly effective for patients who do not respond adequately to topical corticosteroids or calcineurin inhibitors. **2. Why Other Options are Incorrect:** * **Pemphigus:** This is an autoimmune blistering disease treated primarily with systemic corticosteroids and immunosuppressants (e.g., Azathioprine, Rituximab). * **Psoriasis:** Chloroquine is generally **contraindicated** in psoriasis as it can trigger a flare-up or cause the disease to transition into a more severe form, such as erythrodermic or pustular psoriasis. * **Nummular Eczema:** This is an inflammatory skin condition treated with emollients, topical steroids, and phototherapy; antimalarials have no role in its management. **3. NEET-PG High-Yield Pearls:** * **Ocular Toxicity:** The most significant side effect of long-term Chloroquine use is **retinopathy** (Bull’s eye maculopathy). Baseline and periodic ophthalmological exams are mandatory. * **Other Indications:** Antimalarials are also used in Systemic Lupus Erythematosus (SLE), Porphyria Cutanea Tarda (PCT), and Polymorphous Light Eruption (PMLE). * **Smoking Interference:** Smoking significantly reduces the clinical efficacy of antimalarials in patients with cutaneous lupus.

Question 70: Lupus erythematosus is:

A. A reactive lesion
B. A degenerative condition
C. An autoimmune disorder (Correct Answer)
D. A neoplastic condition

Explanation: **Explanation:** **Lupus Erythematosus (LE)** is a chronic inflammatory disease characterized by the loss of self-tolerance, leading to the production of **autoantibodies** (such as ANA and anti-dsDNA) and the formation of immune complexes. These complexes deposit in various tissues, triggering a Type III hypersensitivity reaction that causes multi-organ damage. In dermatology, this spectrum ranges from **Discoid Lupus Erythematosus (DLE)**, which is skin-limited, to **Systemic Lupus Erythematosus (SLE)**, which involves internal organs. **Analysis of Options:** * **Reactive lesion (A):** These are non-neoplastic growths or inflammatory responses to a specific stimulus (e.g., trauma or infection), such as Pyogenic Granuloma. LE is an endogenous immune dysfunction, not a simple reaction to external stimuli. * **Degenerative condition (B):** These involve the progressive deterioration of tissues due to aging or wear-and-tear (e.g., Osteoarthritis). While LE causes tissue damage, the primary mechanism is active inflammation, not degeneration. * **Neoplastic condition (D):** Neoplasia refers to autonomous, abnormal cell proliferation (cancer). While chronic DLE scars can rarely undergo malignant transformation into Squamous Cell Carcinoma, LE itself is not a malignancy. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark Histopathology:** Interface dermatitis with vacuolar degeneration of the basal layer and "follicular plugging." * **Direct Immunofluorescence (DIF):** The **Lupus Band Test** shows granular IgG and C3 deposits at the dermo-epidermal junction. * **Drug-Induced Lupus:** Most commonly associated with **Procainamide** and **Hydralazine**; characteristically shows **Anti-Histone antibodies** and spares the kidneys. * **Most Specific Marker for SLE:** Anti-Smith (Anti-Sm) and Anti-dsDNA antibodies.

Practice by Chapter

Lupus Erythematosus: Cutaneous Forms

Practice Questions

Lupus Erythematosus: Systemic with Skin Manifestations

Practice Questions

Dermatomyositis

Practice Questions

Scleroderma and Morphea

Practice Questions

Mixed Connective Tissue Disease

Practice Questions

Sjögren's Syndrome: Cutaneous Manifestations

Practice Questions

Relapsing Polychondritis

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Autoimmune Thyroid Disease and the Skin

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Immunobullous Disorders

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Vasculitis

Practice Questions

Diagnostic Methods in Autoimmune Dermatoses

Practice Questions

Management of Autoimmune Skin Diseases

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