Autoimmune Skin Diseases Practice Questions

Q: The following lesion appears on the cheek of a patient of ulcerative colitis. It subsided with potassium iodide treatment. What is the diagnosis?

Pyoderma gangrenosum. ***Pyoderma gangrenosum*** - Pyoderma gangrenosum is a **neutrophilic dermatosis** strongly associated with **inflammatory bowel disease** (particularly ulcerative colitis in 50% of cases). - Presents as rapidly progressive, painful **ulcerative lesions** with characteristic **violaceous, undermined borders**. - While classically found on the **lower extremities**, it can occur at any site including the face (rare). - **Standard treatment** includes systemic corticosteroids, cyclosporine, and biologics (anti-TNF agents). - Note: Potassium iodide is **not a standard therapy** for pyoderma gangrenosum; this represents an unusual treatment response if documented in this case. *Erythema nodosum* - Presents as **tender, erythematous nodules** (panniculitis) typically on the **anterior shins**. - Can be associated with inflammatory bowel disease as an extraintestinal manifestation. - Rarely presents on the face; lesions are **non-ulcerative**. - May respond to **potassium iodide** in some cases, but the lesion morphology (ulcerative) does not fit. *Erythema marginatum* - A rare cutaneous manifestation of **acute rheumatic fever**. - Presents as **pink or red annular lesions** with central clearing and serpiginous borders on trunk and proximal extremities. - **Not associated** with inflammatory bowel disease. - Does not present as ulcerative lesions. *Sweet syndrome* - **Acute febrile neutrophilic dermatosis** presenting with **tender, erythematous plaques and nodules**. - Can be associated with inflammatory bowel disease. - Typically affects the **face, neck, and upper extremities**. - Lesions are characteristically **non-ulcerative** (unlike pyoderma gangrenosum). - Does not respond to potassium iodide; treatment is systemic corticosteroids.

Q: The lesion shown below is seen in:

Scleroderma. ***Scleroderma*** - The image displays **sclerodactyly**, characterized by tight, shiny skin on the fingers, and possible **Raynaud's phenomenon** (seen as bluish discoloration of the digits), which are classic features of scleroderma. - The skin appears indurated and thickened, particularly over the joints, consistent with **systemic sclerosis**. *Guttate psoriasis* - This condition presents with small, **tear-drop shaped**, red, scaly plaques, often appearing suddenly after an infection, which are not depicted in the image. - It typically affects the trunk and proximal extremities, rather than causing the specific hand changes shown. *Dermatomyositis* - Characterized by a distinctive **heliotrope rash** on the eyelids and **Gottron's papules** (red-purple plaques over the knuckles), which are absent here. - **Mechanic's hands**, another feature, involves hyperkeratotic, fissured skin but doesn't typically present with the overall skin tightness and shininess seen. *Pustular psoriasis* - This severe form of psoriasis involves widespread erythema and sterile **pustules**, which coalesce and can lead to systemic symptoms. - The image does not show any pustular lesions, nor the generalized inflammation characteristic of pustular psoriasis.

Q: All are true about the lesions shown except:

Non pruritic. ***Non pruritic*** - The lesions shown are characteristic of **Lichen Planus**, which is classically described as intensely **pruritic**. - **Pruritus** is a hallmark symptom of lichen planus, often preceding the appearance of the rash. - Since the question asks "all are true **EXCEPT**", this is the **correct answer** as it is the FALSE statement. *Violaceous lesions* - **Lichen Planus** typically presents with **violaceous**, polygonal, planar, pruritic papules and plaques. - The image indeed shows lesions with a purplish or violaceous hue. - This is a TRUE statement about lichen planus. *Wickham Striae* - **Wickham Striae** are fine, white, lacy patterns seen on the surface of papules in lichen planus, especially when examined with a dermatoscope or magnification. - These are a distinctive and diagnostic feature of **lichen planus**, indicating areas of hypertrophic stratum granulosum. - This is a TRUE statement about lichen planus. *Saw tooth appearance of rete ridges* - On **histopathology**, lichen planus is characterized by a **"sawtooth" appearance of the rete ridges** due to irregular epidermal proliferation and a dense, band-like lymphocytic infiltrate at the dermo-epidermal junction. - This is a key microscopic feature for diagnosing **lichen planus**. - This is a TRUE statement about lichen planus.

Q: All are true about the lesion shown below except:

Seen in chronic renal failure. The image shows **Erythema Multiforme (EM)**, characterized by target (iris) lesions with a predilection for acral areas. ***Correct Answer: Seen in chronic renal failure*** - Erythema Multiforme is **NOT associated with chronic renal failure** - EM is a **hypersensitivity reaction** most commonly triggered by infections (especially HSV, Mycoplasma) or drugs - Chronic renal failure is associated with other dermatologic conditions like **pseudoporphyria**, **acquired perforating dermatosis**, and **calciphylaxis**, but NOT Erythema Multiforme - This is the FALSE statement, making it the correct answer to this EXCEPT question *Incorrect: Target lesions* - **Target (iris) lesions are PATHOGNOMONIC for Erythema Multiforme** - These appear as concentric zones of color change with a dusky central area, surrounded by pale edema, and an outer erythematous ring - The "three-zone" target lesion is the hallmark feature that distinguishes EM from other conditions - This statement is TRUE, so it is NOT the answer to this EXCEPT question *Incorrect: Crops heal with Hyperpigmentation* - **TRUE** - EM lesions typically heal with post-inflammatory hyperpigmentation, especially in darker skin types - The lesions appear in crops over 3-5 days and resolve over 1-2 weeks - No scarring occurs, but pigmentary changes may persist for weeks to months - This statement is TRUE, so it is NOT the answer to this EXCEPT question *Incorrect: Predominant on acral and face area* - **TRUE** - EM has a characteristic **acral distribution** - Lesions favor the **extensor surfaces of distal extremities** (dorsum of hands, feet, elbows, knees) - **Palms, soles, and face** are commonly involved - This acral predominance distinguishes EM from other erythematous eruptions - This statement is TRUE, so it is NOT the answer to this EXCEPT question

Q: All are true about the skin disease shown except:

Paronychia. ***Paronychia*** - Paronychia refers to inflammation of the **nail folds**, which is not depicted in the image. The image shows blistering skin lesions typical of a bullous dermatosis. - This condition is commonly due to infection (bacterial or fungal) or irritation around the nails, distinct from the generalized blistering seen here. *Bulla spread sign* - The image depicts a **positive Nikolsky's sign**, also known as the bulla spread sign, where gentle lateral pressure on unbroken skin near a blister causes the blister to extend. - This sign is characteristic of **pemphigus vulgaris**, indicating intraepidermal blistering due to loss of cell-to-cell adhesion. *IgG antibodies along keratinocyte cell membrane give fish net appearance* - Pemphigus vulgaris is characterized by the presence of **IgG autoantibodies** targeting desmoglein 1 and 3, components of desmosomes between keratinocytes. - On direct immunofluorescence, these antibodies appear as a **"fish-net" pattern** of IgG deposition around individual keratinocytes, a hallmark finding for pemphigus. *Acantholysis on histopathology* - **Acantholysis** is the loss of intercellular connections (desmosomes) between keratinocytes, resulting in separation of epidermal cells. - This is a **hallmark histopathologic feature of pemphigus vulgaris**, with keratinocytes appearing rounded and separated, forming intraepidermal blisters with a characteristic "tombstone" appearance of basal cells at the blister base.

Q: A patient presents with the skin lesions shown in the image. While evaluating for possible blistering disorders, all of the following conditions could present with similar morphology EXCEPT:

Bullous pemphigoid. ***Bullous pemphigoid*** - Presents with **tense bullae** on an erythematous base, typically in elderly patients, unlike the **umbilicated papules** seen in this image. - Involves **subepidermal blistering** with **linear IgG deposition** at the basement membrane zone, not the viral inclusions of Molluscum contagiosum. *Pemphigus vegetans* - A rare variant of pemphigus vulgaris characterized by **vegetating plaques and pustules** in intertriginous areas, not discrete umbilicated lesions. - Shows **intraepidermal acantholysis** with **suprabasal clefting**, histologically distinct from the viral cytopathic changes in Molluscum contagiosum. *Pemphigus vulgaris* - Presents with **flaccid bullae** and painful **mucosal erosions** due to **autoantibodies against desmoglein 1 and 3**. - The **Nikolsky sign** is positive, and lesions are erosive rather than the solid, pearl-like papules characteristic of Molluscum contagiosum. *Pemphigus erythematosus* - Features **erythematous, scaly, crusted lesions** primarily on the **face and upper trunk** with a butterfly distribution. - Combines features of **lupus erythematosus** and pemphigus foliaceus, showing superficial blistering unlike the viral papules in this case.

Q: The following image shows a flaccid bulla. This finding is characteristically seen in:

Pemphigus vulgaris. ***Pemphigus vulgaris*** - The image shows a **flaccid bulla** with purulent fluid, characteristic of **pemphigus vulgaris**. This condition is marked by autoantibodies against desmogleins 1 and 3, which are crucial for keratinocyte adhesion, leading to **intraepidermal blistering** and the **Nikolsky sign**. - The flaccid nature of the bulla, often leading to easy rupture and erosions, is a hallmark of superficial blistering in pemphigus vulgaris, caused by the **loss of cell-to-cell adhesion** within the epidermis. *Pemphigus vegetans* - This is a rare variant of pemphigus vulgaris characterized by **vegetating plaques** and **hyperkeratotic lesions**, particularly in intertriginous areas. - While it starts with bullae, the predominant feature is the development of fungating, vegetative lesions rather than the flaccid bulla seen here. *Pemphigus erythematosus* - Pemphigus erythematosus, also known as Senear-Usher syndrome, is considered a localized form of pemphigus foliaceus with features of **lupus erythematosus**. - It presents with **scaling, crusting, and erythematous lesions** resembling lupus, along with superficial bullae, typically on the face and scalp. *Bullous pemphigoid* - Bullous pemphigoid typically presents with **tense bullae** that are less prone to rupture, unlike the flaccid bulla shown in the image. - It is caused by autoantibodies against hemidesmosomal proteins (BP180 and BP230), resulting in **subepidermal blistering**, meaning the blister forms below the epidermis and is therefore more resilient.

Q: The image shows:

Allergic shiners. ***Allergic shiners*** - The image clearly displays **dark, discolored patches under the eyes**, which are characteristic of allergic shiners. - These are caused by **venous congestion** and extravasation of deoxygenated blood secondary to inflammation or chronic nasal congestion, often associated with allergies. *Allergic salute* - The allergic salute is a **physical maneuver**, where a person rubs their nose upwards with their palm, not a visible sign in this static image. - It results in a **transverse crease across the nasal bridge** over time, which is not what the image shows. *Allergic line* - An "allergic line" or "allergic crease" typically refers to the **transverse nasal crease** caused by the allergic salute, which is not depicted here. - There is no such specific medical term as an "allergic line" referring to the suborbital discoloration shown. *Dennis Morgan's fold* - A Dennis-Morgan fold (more commonly **Dennie-Morgan fold**) is an **extra fold or crease in the skin below the lower eyelid**, often associated with allergic conditions like atopic dermatitis. - While related to allergies, the term more precisely describes this specific **skin fold**, and the image predominantly shows the diffuse dark discoloration, which is the defining characteristic of allergic shiners.

Q: Which of the following vesico-bullous disorders will exhibit the direct immunofluorescence shown below? (Recent NEET Pattern 2016-17)

Pemphigus vulgaris. ***Pemphigus vulgaris*** - The direct immunofluorescence image shows a characteristic **"chicken wire"** or **intercellular** staining pattern in the epidermis. - This pattern indicates the presence of autoantibodies (typically **IgG**) targeting **desmoglein 1 and 3** in the desmosomes, leading to intraepidermal blistering, which is a hallmark of pemphigus vulgaris. *Bullous pemphigoid* - Direct immunofluorescence in bullous pemphigoid typically shows a **linear deposition of IgG and C3 along the dermal-epidermal junction** (basement membrane zone). - This pattern is distinctly different from the intercellular epidermal staining seen in the image. *Cicatricial pemphigoid* - This condition also presents with **linear deposition of immunoreactants along the basement membrane zone**, similar to bullous pemphigoid, but with a different antigen target. - The image does not show a linear basement membrane pattern, ruling out cicatricial pemphigoid. *Chronic bullous dermatosis of childhood* - Also known as **linear IgA bullous dermatosis**, it is characterized by a **linear deposition of IgA along the basement membrane zone**. - The image clearly displays an intercellular staining pattern within the epidermis, not a linear pattern at the dermal-epidermal junction.

Q: A 9-year-old girl presents with pigmentation over forehead and redness over upper eyelids. On physical examination following clinical sign was elicited. What is the next best step for diagnosis?

CK level. ***CK level*** - The combination of **Gottron's papules** (pigmentation over joints), **Heliotrope rash** (redness over upper eyelids), and difficulty standing up as depicted (suggesting **proximal muscle weakness**) are classic signs of **dermatomyositis**, especially in a child. - **Creatine Kinase (CK)** is a key enzyme released by damaged muscle fibers, making its measurement the most appropriate initial diagnostic step to assess for muscle inflammation and damage in dermatomyositis. *Rheumatoid factor* - **Rheumatoid factor (RF)** is primarily associated with **rheumatoid arthritis**, which typically affects joints and not primarily the skin or proximal muscles in the manner described. - While some autoimmune conditions can overlap, RF is not a primary diagnostic marker for dermatomyositis. *Electromyography* - **Electromyography (EMG)** measures muscle electrical activity and can indeed show abnormalities in dermatomyositis (e.g., fibrillation potentials, positive sharp waves, and polyphasic motor unit potentials). - However, it is typically a **secondary diagnostic step** performed after initial biochemical tests like CK levels indicate muscle involvement. *Nerve conduction studies* - **Nerve conduction studies (NCS)** assess the function of peripheral nerves and are primarily used to diagnose **neuropathies**. - Dermatomyositis is a **myopathy** (muscle disease) not a neuropathy, so NCS would likely be normal or show non-specific findings, making it less relevant for initial diagnosis.

Question 1

The following lesion appears on the cheek of a patient of ulcerative colitis. It subsided with potassium iodide treatment. What is the diagnosis?

Accepted Answer

Pyoderma gangrenosum

Answer

Erythema nodosum

Answer

Erythema marginatum

Answer

Sweet syndrome

Question 2

The lesion shown below is seen in:

Accepted Answer

Scleroderma

Answer

Guttate psoriasis

Answer

Dermatomyositis

Answer

Pustular psoriasis

Question 3

All are true about the lesions shown except:

Accepted Answer

Non pruritic

Answer

Violaceous lesions

Answer

Wickham Striae

Answer

Saw tooth appearance of rete ridges

Question 4

All are true about the lesion shown below except:

Accepted Answer

Seen in chronic renal failure

Answer

Target lesions

Answer

Crops heal with Hyper-pigmentation

Answer

Predominant on acral and face area

Question 5

All are true about the skin disease shown except:

Accepted Answer

Paronychia

Answer

Bulla spread sign

Answer

IgG antibodies along keratinocyte cell membrane give fish net appearance

Answer

Acantholysis on histopathology

Question 6

A patient presents with the skin lesions shown in the image. While evaluating for possible blistering disorders, all of the following conditions could present with similar morphology EXCEPT:

Accepted Answer

Bullous pemphigoid

Answer

Pemphigus vulgaris

Answer

Pemphigus erythematosus

Answer

Pemphigus vegetans

Question 7

The following image shows a flaccid bulla. This finding is characteristically seen in:

Accepted Answer

Pemphigus vulgaris

Answer

Pemphigus vegetans

Answer

Pemphigus erythematosus

Answer

Bullous pemphigoid

Question 8

The image shows:

Accepted Answer

Allergic shiners

Answer

Allergic salute

Answer

Allergic line

Answer

Dennie-Morgan fold

Question 9

Which of the following vesico-bullous disorders will exhibit the direct immunofluorescence shown below? (Recent NEET Pattern 2016-17)

Accepted Answer

Pemphigus vulgaris

Answer

Bullous pemphigoid

Answer

Cicatricial pemphigoid

Answer

Chronic bullous dermatosis of childhood

Question 10

A 9-year-old girl presents with pigmentation over forehead and redness over upper eyelids. On physical examination following clinical sign was elicited. What is the next best step for diagnosis?

Accepted Answer

CK level

Answer

Rheumatoid factor

Answer

Electromyography

Answer

Nerve conduction studies

Autoimmune Skin Diseases — MCQs

Autoimmune Skin Diseases — MCQs

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