Autoimmune Skin Diseases Practice Questions

Q: Lupus erythematosus is:

An autoimmune disorder. **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.

Q: What is the term used to refer to hidebound disease?

Scleroderma. **Explanation:** **Scleroderma** (Systemic Sclerosis) is referred to as **"Hidebound disease"** because of the characteristic progressive fibrosis and thickening of the skin. The term "hidebound" literally describes skin that is so tight and bound to the underlying subcutaneous structures that it cannot be pinched or moved. This occurs due to excessive collagen deposition, leading to the loss of skin elasticity. **Analysis of Options:** * **Scleroderma (Correct):** In addition to hidebound skin, clinical features include **Microstomia** (fish-mouth appearance), **Sclerodactyly** (tapering of fingers), and **Raynaud’s phenomenon** (often the earliest sign). * **Discoid Lupus Erythematosus (DLE):** This is a chronic cutaneous form of Lupus characterized by well-defined erythematous scaly plaques, follicular plugging, and scarring alopecia. It does not cause the generalized "hidebound" tightening seen in scleroderma. * **Acrodermatitis Enteropathica:** This is an autosomal recessive disorder caused by **Zinc deficiency**. It presents with a triad of periorificial/acral dermatitis, alopecia, and diarrhea, but does not involve skin fibrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Salt and Pepper Pigmentation:** A classic sign of Scleroderma characterized by vitiligo-like depigmentation with sparing of the perifollicular areas. * **CREST Syndrome:** A limited form of systemic sclerosis (Calcinosis, Raynaud’s, Esophageal dysmotility, Sclerodactyly, Telangiectasia). * **Antibody Markers:** **Anti-Scl-70** (Topoisomerase I) is specific for Diffuse Systemic Sclerosis, while **Anti-Centromere** antibody is specific for Limited Scleroderma (CREST). * **En coup de sabre:** A linear form of localized scleroderma (morphea) occurring on the scalp or forehead.

Q: Gottron's sign is characteristic of which condition?

Dermatomyositis. **Explanation:** **Dermatomyositis** is the correct answer. **Gottron’s sign** is a pathognomonic clinical feature of this idiopathic inflammatory myopathy. It presents as symmetric, erythematous to violaceous macules or plaques located over the dorsal aspect of the interphalangeal and metacarpophalangeal joints. These lesions may sometimes become atrophic or scaly. It is distinct from **Gottron’s papules**, which are palpable, lichenoid papules in the same distribution. **Analysis of Incorrect Options:** * **Lupus Erythematosus (SLE):** While SLE also presents with photosensitive rashes, the classic malar rash spares the nasolabial folds. Crucially, hand involvement in SLE typically affects the **interarticular skin** (the skin between the joints), specifically sparing the knuckles, which helps differentiate it from Dermatomyositis. * **Scleroderma:** This condition is characterized by skin thickening and tightening (sclerodactyly) and Raynaud’s phenomenon, but it does not feature Gottron’s sign. * **Bell’s Palsy:** This is an isolated lower motor neuron facial nerve palsy and has no primary dermatological manifestations. **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 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 is frequently associated with internal malignancies (paraneoplastic syndrome).

Q: What is the percentage of patients with disseminated discoid lupus erythematosus who develop systemic lupus erythematosus?

22%. **Explanation:** The progression of Discoid Lupus Erythematosus (DLE) to Systemic Lupus Erythematosus (SLE) depends significantly on the distribution of skin lesions. DLE is categorized into two types: **Localized** (lesions confined to the head and neck) and **Disseminated** (lesions occurring both above and below the neck). 1. **Why 22% is correct:** While only about **5%** of patients with localized DLE progress to SLE, the risk increases significantly in the disseminated form. Clinical studies and standard dermatology textbooks (such as Fitzpatrick) indicate that approximately **22%** of patients with disseminated DLE will eventually develop systemic involvement. The presence of lesions on the trunk and extremities often correlates with a higher frequency of immunological abnormalities (like ANA positivity). 2. **Why other options are incorrect:** * **A (2%):** This is too low; even localized DLE has a higher conversion rate (~5%). * **C (52%) & D (82%):** These figures are overestimates. While disseminated DLE carries a higher risk than localized DLE, the majority of patients (nearly 80%) still do not develop full-blown systemic disease. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for DLE:** The concha of the ear. * **Classic Histology:** Interface dermatitis, follicular plugging, and basement membrane thickening. * **Lupus Band Test (LBT):** In DLE, the LBT is positive in **lesional skin** only. In SLE, the LBT can be positive in both lesional and **sun-exposed non-lesional skin**. * **Risk Factor:** Patients with disseminated DLE and high-titer ANA are at the highest risk for progression to SLE.

Q: Granular deposit of IgA at the dermoepidermal junction is seen in which of the following conditions?

Dermatitis herpetiformis. **Explanation:** The correct answer is **Dermatitis herpetiformis (DH)**. This condition is a cutaneous manifestation of gluten-sensitive enteropathy (Celiac disease). The hallmark immunopathological finding in DH is the **granular deposition of IgA** at the tips of the dermal papillae (dermoepidermal junction). These deposits are directed against **epidermal transglutaminase (eTG)**. **Why the other options are incorrect:** * **Pemphigus vulgaris:** Characterized by **IgG and C3** deposits in a **"fish-net" or "lace-like"** pattern within the epidermis (intercellular), targeting Desmoglein 3. * **Bullous pemphigoid:** Shows **linear** (not granular) deposition of **IgG and C3** along the basement membrane zone (BMZ), targeting BP180 and BP230. * **Pemphigus foliaceus:** Similar to Pemphigus vulgaris, it shows a **fish-net IgG** pattern, but it is localized to the superficial layers of the epidermis, targeting Desmoglein 1. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Intensely pruritic, grouped vesicles (herpetiform) symmetrically distributed on extensor surfaces (elbows, knees, buttocks). * **Histopathology:** Characterized by **neutrophilic microabscesses** (Papillary tip abscesses) and subepidermal blisters. * **Association:** Strongly associated with **HLA-DQ2 and HLA-DQ8**. * **Treatment of Choice:** **Dapsone** (provides rapid symptomatic relief) along with a strict **gluten-free diet**. * **Gold Standard Diagnosis:** Direct Immunofluorescence (DIF) of perilesional skin showing granular IgA.

Q: IgA deposits are seen on a skin biopsy in which of the following conditions?

Henoch-Schonlein purpura. **Explanation:** **Henoch-Schönlein Purpura (HSP)**, also known as **IgA Vasculitis**, is the correct answer because it is a small-vessel vasculitis characterized by the deposition of **IgA-dominant immune complexes** in the walls of small vessels (capillaries, venules, or arterioles). On Direct Immunofluorescence (DIF) of a skin biopsy, the hallmark finding is granular IgA deposits within the dermal vessel walls. Clinically, this presents as the classic tetrad of palpable purpura, arthralgia, abdominal pain, and renal involvement (IgA nephropathy). **Analysis of Incorrect Options:** * **B. Giant Cell Arteritis:** This is a large-vessel vasculitis. Diagnosis is made via temporal artery biopsy showing granulomatous inflammation; it is not characterized by IgA deposits. * **C. Microscopic Polyangiitis (MPA):** This is a small-vessel vasculitis associated with **p-ANCA** (anti-MPO). It is a "pauci-immune" vasculitis, meaning there are little to no immunoglobulin deposits on immunofluorescence. * **D. Wegener’s Granulomatosis (GPA):** Now called Granulomatosis with Polyangiitis, this is a small-vessel vasculitis associated with **c-ANCA** (anti-PR3). Like MPA, it is pauci-immune and lacks significant IgA deposition. **High-Yield Clinical Pearls for NEET-PG:** * **DIF in Dermatology:** IgA deposits are also the hallmark of **Dermatitis Herpetiformis** (granular deposits at the tips of dermal papillae) and **Linear IgA Bullous Dermatosis** (linear deposits along the BMZ). * **HSP Trigger:** Often follows an Upper Respiratory Tract Infection (URTI). * **Biopsy Timing:** For vasculitis, the best site for biopsy is a fresh lesion (<24–48 hours old) to capture the immune deposits before they are degraded by inflammation.

Q: A 45-year-old patient presents with itchy, flat-topped, polygonal, violaceous papules on the inner wrists and flexors surfaces of the forearms. The lesions have a characteristic shiny surface and are arranged in a linear pattern. The patient denies any recent medication changes. What is the treatment?

Topical steroids. ***Topical steroids***- **Lichen planus** is an inflammatory, immune-mediated disorder, and high-potency **topical corticosteroids** are the first-line treatment for localized cutaneous disease on flexural surfaces.- They reduce the inflammation (T-cell-mediated injury to the **basal layer** of the epidermis) and effectively alleviate symptoms like intense **pruritus** (itching).*Antibiotics*- Lichen planus is a **sterile inflammatory process**, not caused by a bacterial infection, making antibiotics ineffective for treating the underlying pathology.- Antibiotics are reserved for infectious conditions like cellulitis or **secondary bacterial infection** of the lesions, which is not indicated here.*Immunosuppressants*- Systemic **immunosuppressants** (e.g., methotrexate, cyclosporine) are reserved for severe, widespread, or treatment-refractory cases, or extensive subtypes like **erosive oral lichen planus**.- For localized cutaneous disease, the risk profile of systemic immunosuppression does not justify its use over topical therapy.*Anti-fungal*- Anti-fungal agents are used to treat infections caused by fungi, such as **Tinea corporis** (ringworm), which presents with scaly, erythematous plaques, not flat-topped violaceous papules.- Lichen planus is an autoimmune/inflammatory dermatosis; therefore, anti-fungals have no role in its primary management.

Q: A patient presented with itchy lesions, as shown below. What is the diagnosis?

Lichen planus. ***Lichen planus*** - The image displays classic features of lichen planus, which are often described by the **'5 P's'**: **P**ruritic (itchy), **P**olygonal, **P**lanar (flat-topped), **P**urple **P**apules and plaques. - A characteristic sign, though not always clearly visible, is the presence of fine white lines on the surface of the lesions, known as **Wickham's striae**. It is also associated with **Hepatitis C** infection. *Scabies* - Scabies presents with intensely pruritic small papules, vesicles, and pathognomonic **burrows**, which are not seen in the image. The lesions shown are large plaques, not typical for a mite infestation. - The distribution of scabies is characteristic, favoring **finger web spaces**, wrists, axillae, and the genital area, whereas the lesions shown are on a broader surface. *Psoriasis* - Psoriasis typically appears as well-demarcated, erythematous plaques covered with a thick, **silvery-white scale**. The lesions in the image are violaceous and lack the prominent silvery scale. - A key clinical sign in psoriasis is the **Auspitz sign**, where pinpoint bleeding occurs after the scale is removed. Lesions are commonly found on **extensor surfaces** like the elbows and knees. *Warts* - Warts (verruca vulgaris) are caused by the **Human Papillomavirus (HPV)** and present as hyperkeratotic, exophytic papules with a rough, papillomatous surface, unlike the flat-topped lesions in the image. - On close inspection, warts often show thrombosed capillaries appearing as **black dots** (pepper pot sign), which are absent in these lesions.

Q: A patient presents with a violaceous rash on the upper back and shoulders (img-16.jpeg) and Gottron's papules on hands (img-17.jpeg). What is the likely diagnosis?

Dermatomyositis. ***Dermatomyositis*** - The presence of a **heliotrope rash** (violaceous eruption on the upper eyelids) and **Gottron's papules** (violaceous papules over the knuckles) are pathognomonic for this inflammatory myopathy. - Other characteristic skin findings include the **shawl sign** (a photosensitive rash on the upper back, shoulders, and posterior neck, as seen in the image), the **V-sign**, and associated proximal muscle weakness. *Systemic lupus erythematosus* - SLE is classically associated with a **malar rash** (butterfly rash) over the bridge of the nose and cheeks, which spares the nasolabial folds. - While photosensitivity is a common feature, the specific findings of a heliotrope rash and Gottron's papules are not typical for SLE. *Systemic sclerosis* - This condition is characterized by progressive **skin thickening** and fibrosis, particularly **sclerodactyly** (tightening of the skin on the fingers). - Key differentiating features include **Raynaud phenomenon** and internal organ involvement, which are absent in this presentation. *Cushing syndrome* - This endocrine disorder is caused by excess **cortisol** and presents with distinct features like a **moon face**, **buffalo hump**, and purple **striae**. - It does not cause the inflammatory, photosensitive rashes that are characteristic of dermatomyositis.

Question 1

Lupus erythematosus is:

Accepted Answer

An autoimmune disorder

Answer

A reactive lesion

Answer

A degenerative condition

Answer

A neoplastic condition

Question 2

A 2-year-old child, born out of a consanguineous marriage, presented with a history of collodion membrane. Physical examination revealed large, thick, plate-like brown scaling with generalized distribution, but no erythroderma or ectropion. Which of the following is the most likely diagnosis?

Accepted Answer

Lamellar ichthyosis

Answer

Ichthyosis vulgaris

Answer

X-linked ichthyosis

Answer

Netherton syndrome

Question 3

What is the term used to refer to hidebound disease?

Accepted Answer

Scleroderma

Answer

Discoid Lupus Erythematosus (DLE)

Answer

Acrodermatitis enteropathica

Answer

None of the above

Question 4

Gottron's sign is characteristic of which condition?

Accepted Answer

Dermatomyositis

Answer

Lupus erythematosus

Answer

Scleroderma

Answer

Bell's palsy

Question 5

What is the percentage of patients with disseminated discoid lupus erythematosus who develop systemic lupus erythematosus?

Accepted Answer

22%

Answer

2%

Answer

52%

Answer

82%

Question 6

Granular deposit of IgA at the dermoepidermal junction is seen in which of the following conditions?

Accepted Answer

Dermatitis herpetiformis

Answer

Pemphigus vulgaris

Answer

Bullous pemphigoid

Answer

Pemphigus foliaceus

Question 7

IgA deposits are seen on a skin biopsy in which of the following conditions?

Accepted Answer

Henoch-Schonlein purpura

Answer

Giant cell arteritis

Answer

Microscopic polyangiitis

Answer

Wegener's granulomatosis

Question 8

A 45-year-old patient presents with itchy, flat-topped, polygonal, violaceous papules on the inner wrists and flexors surfaces of the forearms. The lesions have a characteristic shiny surface and are arranged in a linear pattern. The patient denies any recent medication changes. What is the treatment?

Accepted Answer

Topical steroids

Answer

Anti-fungal

Answer

Antibiotics

Answer

Immunosuppressants

Question 9

A patient presented with itchy lesions, as shown below. What is the diagnosis?

Accepted Answer

Lichen planus

Answer

Scabies

Answer

Psoriasis

Answer

Warts

Question 10

A patient presents with a violaceous rash on the upper back and shoulders (img-16.jpeg) and Gottron's papules on hands (img-17.jpeg). What is the likely diagnosis?

Accepted Answer

Dermatomyositis

Answer

Systemic lupus erythematosus

Answer

Systemic sclerosis

Answer

Cushing syndrome

Autoimmune Skin Diseases — MCQs

Autoimmune Skin Diseases — MCQs

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