Dermatomyositis — MCQs
A 10-year-old boy presents with fever, joint pain, and a lesion over his hand, as seen in the image below. Which of the following is the clinical finding, and what is the likely diagnosis?
A 50-year-old male patient presented with weakness of bilateral lower limbs which was symmetrical (distal weakness >> proximal muscle weakness) for 1 month. On examination, certain skin and nail changes were noted. Patient also complained of myalgia and arthralgia. Lab findings: Raised creatinine kinase levels, Raised ANA antibody titre. Muscle biopsy was done from the quadriceps femoris muscle. CD4+ cells were found in the cellular infiltrate. IHC study of which protein is a very sensitive diagnostic test for the above condition?
Which of the following is not a feature of dermatomyositis?
A 64-year-old man presents to the clinic with generalized weakness, difficulty getting out of a chair and lifting objects above his head, and a 15-pound weight loss. He has a blue-purple rash on his eyelids and knuckles, and his proximal muscle strength is rated 4 out of 5. Laboratory investigations reveal an elevated creatinine kinase (CK) level. He is started on prednisone therapy. Which of the following is the most important in monitoring response to therapy?
Treatment of myositis ossificans includes all except -
Identify the lesion:
A 26-year-old female patient presented with oral ulcers, sensitivity to light and rash over the malar area of the face sparing the nasolabial folds of both sides. Which of the following is most characteristic of this condition?
Cutis marmorata occurs due to exposure to –
The mode of inheritance of Incontinentia pigmenti is:
A study of persons developing skin lesions following sun exposure is conducted. The lesions are not found on skin protected from ultraviolet light. Biopsies of involved skin show immunoglobulin G deposition along the dermal-epidermal junction, along with vacuolization of the basal layer and a perivascular lymphocytic infiltrate. No other organ involvement is present. Which of the following diseases do these patients most likely have?
Dermatomyositis Indian Medical PG Practice Questions and MCQs
Question 1: A 10-year-old boy presents with fever, joint pain, and a lesion over his hand, as seen in the image below. Which of the following is the clinical finding, and what is the likely diagnosis?
- A. Malar rash - Systemic lupus erythematosus
- B. Heliotrope rash - Dermatomyositis
- C. Erythema multiforme - Stevens-Johnson syndrome
- D. Gottron's papules - Juvenile dermatomyositis (Correct Answer)
Explanation: ***Gottron's papules - Juvenile dermatomyositis*** - The image clearly displays **Gottron's papules**, which are **erythematous, scaling papules** symmetrically distributed over the **dorsal aspects of the interphalangeal joints** (MCP and PIP joints). - The clinical presentation of a 10-year-old boy with **fever, joint pain**, and these characteristic skin lesions is highly indicative of **juvenile dermatomyositis (JDM)**, an inflammatory myopathy. *Malar rash - Systemic lupus erythematosus* - A **malar rash** is a common finding in **systemic lupus erythematosus (SLE)**, but it typically presents as an **erythematous rash over the cheeks and bridge of the nose**, sparing the nasolabial folds, and does not exhibit the papular, scaly appearance over the knuckles seen in the image. - While SLE can cause fever and joint pain, the specific skin lesion depicted is not consistent with a malar rash. *Heliotrope rash - Dermatomyositis* - A **heliotrope rash** is another classic skin manifestation of **dermatomyositis**, characterized by a **purplish discoloration around the eyelids**, often accompanied by periorbital edema. - This is distinct from the lesions shown on the knuckles, which are diagnostic of Gottron's papules, not a heliotrope rash. *Erythema multiforme - Stevens-Johnson syndrome* - **Erythema multiforme** is characterized by **targetoid lesions** with concentric rings, often appearing acutely in response to infections or medications. - **Stevens-Johnson syndrome (SJS)** is a severe form of erythema multiforme, involving extensive epidermal detachment and mucosal involvement, which does not match the chronic-appearing, papular lesions on the knuckles in the image.
Question 2: A 50-year-old male patient presented with weakness of bilateral lower limbs which was symmetrical (distal weakness >> proximal muscle weakness) for 1 month. On examination, certain skin and nail changes were noted. Patient also complained of myalgia and arthralgia. Lab findings: Raised creatinine kinase levels, Raised ANA antibody titre. Muscle biopsy was done from the quadriceps femoris muscle. CD4+ cells were found in the cellular infiltrate. IHC study of which protein is a very sensitive diagnostic test for the above condition?
- A. Myxovirus resistance protein (Correct Answer)
- B. Adenovirus resistance protein
- C. Parvovirus resistance protein
- D. Papovavirus resistance protein
Explanation: ***Myxovirus resistance protein*** - The clinical presentation suggests **dermatomyositis** or **polymyositis**, characterized by symmetrical muscle weakness, skin/nail changes, myalgia, arthralgia, and elevated CK/ANA [1]. - In these conditions, **Type I interferon (IFN-I)** activation occurs, leading to increased expression of **myxovirus resistance protein A (MxA)**, which serves as a highly sensitive biomarker. *Adenovirus resistance protein* - This is not a recognized or specific biomarker for **inflammatory myopathies** like dermatomyositis or polymyositis. - While adenoviruses can cause muscle inflammation in certain contexts, related resistance proteins are not used for diagnosis in this manner. *Parvovirus resistance protein* - Parvovirus B19 can cause myositis, but "parvovirus resistance protein" is not a specific or sensitive diagnostic marker for **idiopathic inflammatory myopathies**. - The associated immune response and biomarkers would relate more directly to the viral infection itself. *Papovavirus resistance protein* - **Papovaviruses** (e.g., human papillomavirus, JC virus) are not typically associated with **idiopathic inflammatory myopathies**. - There is no "papovavirus resistance protein" that serves as a diagnostic biomarker for the presented clinical picture.
Question 3: Which of the following is not a feature of dermatomyositis?
- A. Salmon Patch (Correct Answer)
- B. Periungual telangiectasias
- C. Gottron's patch
- D. Mechanic's hands
Explanation: ***Salmon Patch*** - A **salmon patch** (also known as a nevus simplex or stork bite) is a common, benign vascular birthmark that presents as a flat, red or pink patch. - It is **not associated with dermatomyositis** and has no pathogenic link to the condition. *Gottron's patch* - **Gottron's patches** are a classic cutaneous manifestation of dermatomyositis, characterized by erythematous, violaceous, or dusky red papules or plaques over the **extensor surfaces of the metacarpophalangeal and interphalangeal joints**. - Their presence is highly suggestive of dermatomyositis, often preceding or co-occurring with muscle weakness. *Periungual telangiectasias* - **Periungual telangiectasias** are dilated capillaries around the nail folds and are a common skin manifestation of dermatomyositis. - They represent small vessel vasculopathy, a histological feature, and suggest microvascular damage often seen in systemic connective tissue diseases like dermatomyositis. *Mechanic's hands* - **Mechanic's hands** are a cutaneous feature seen in dermatomyositis (and other inflammatory myopathies like antisynthetase syndrome). - They are characterized by **hyperkeratosis**, fissuring, and scaling of the skin, particularly on the lateral and palmar aspects of the fingers, resembling the hands of a manual laborer.
Question 4: A 64-year-old man presents to the clinic with generalized weakness, difficulty getting out of a chair and lifting objects above his head, and a 15-pound weight loss. He has a blue-purple rash on his eyelids and knuckles, and his proximal muscle strength is rated 4 out of 5. Laboratory investigations reveal an elevated creatinine kinase (CK) level. He is started on prednisone therapy. Which of the following is the most important in monitoring response to therapy?
- A. testing of muscle strength (Correct Answer)
- B. sedimentation rates
- C. EMG
- D. serum muscle enzymes (CK)
Explanation: ***testing of muscle strength*** - **Proximal muscle weakness** (difficulty getting out of a chair and lifting objects) is a primary symptom of **dermatomyositis**, which is indicated by the rash and elevated CK [1]. - Monitoring improvement in **muscle strength** directly reflects the patient's functional recovery and response to prednisone, making it the most critical measure [3]. *sedimentation rates* - **Erythrocyte sedimentation rate (ESR)** can be elevated in inflammatory conditions but is a **non-specific marker** of inflammation [2]. - It does not directly correlate with muscle damage or recovery in dermatomyositis, making it less useful for monitoring therapeutic response. *serum muscle enzymes (CK)* - Elevated **creatinine kinase (CK)** levels indicate muscle damage, and while typically elevated in active disease, CK levels can take time to normalize even with effective treatment [2]. - Clinical improvement in **muscle strength** often precedes the complete normalization of CK levels, making functional assessment more immediately relevant for therapeutic adjustments. *EMG* - **Electromyography (EMG)** is a diagnostic tool used to confirm muscle involvement and differentiate myopathic from neuropathic conditions [2]. - While useful for initial diagnosis, it is **not routinely used** for monitoring treatment response due to its invasive nature and lack of direct correlation with daily functional improvement.
Question 5: Treatment of myositis ossificans includes all except -
- A. Splinting elbow
- B. Indometacin
- C. Gentle active movements
- D. Vigorous passive massage (Correct Answer)
Explanation: ***Vigorous passive massage*** - **Vigorous passive massage** is contraindicated in myositis ossificans as it can exacerbate the condition by causing further trauma and promoting heterotopic bone formation. - The goal of treatment is to prevent progression and reduce inflammation, not to aggressively manipulate the affected area. *Splinting elbow* - **Splinting the elbow** in a functional position is a common treatment to help prevent contractures and allow the heterotopic bone to mature. - This immobilization can reduce microtrauma and facilitate healing in the acute phase. *Indometacin* - **Indomethacin**, a non-steroidal anti-inflammatory drug (NSAID), is often used to prevent and treat myositis ossificans. - It works by inhibiting prostaglandin synthesis, which is believed to play a role in the formation of heterotopic bone. *Gentle active movements* - **Gentle active movements** are generally encouraged once the acute inflammatory phase has subsided and the lesion begins to mature. - These movements help maintain range of motion and prevent stiffness without causing excessive trauma that could worsen the condition.
Question 6: Identify the lesion:
- A. Psoriasis
- B. Dermatitis herpetiformis
- C. Erythema marginatum
- D. Dermatomyositis (Correct Answer)
Explanation: ***Dermatomyositis*** - The image shows **Gottron's papules** over the extensor surfaces of the elbows, which are characteristic of dermatomyositis. These are violaceous, erythematous, flat-topped papules. - While typically found on the **dorsum of the hands** over the MCP and IP joints, they can also occur on elbows, knees, and ankles. *Psoriasis* - Psoriasis typically presents with **well-demarcated erythematous plaques** covered with silvery scales, especially on extensor surfaces. - The lesions in the image lack the characteristic **silvery scaling** of psoriasis. *Dermatitis herpetiformis* - This condition presents with intensely **itchy, polymorphic lesions**, including vesicles, bullae, and excoriations, arranged in a symmetrical fashion, often on extensor surfaces. - The lesions in the image are papular and nodular, not exhibiting the characteristic **vesicular or bullous eruption** of dermatitis herpetiformis. *Erythema marginatum* - Erythema marginatum is a **transient, non-pruritic erythematous rash** with serpiginous borders and central clearing, typically seen in **acute rheumatic fever**. - The lesions in the image are fixed papules/nodules without the characteristic migrating or rapidly changing appearance of erythema marginatum.
Question 7: A 26-year-old female patient presented with oral ulcers, sensitivity to light and rash over the malar area of the face sparing the nasolabial folds of both sides. Which of the following is most characteristic of this condition?
- A. Butterfly rash sparing the nasolabial folds (Correct Answer)
- B. Heliotrope rash on upper eyelid, bilateral hilar lymphadenopathy
- C. Port-wine stain with CNS malformations
- D. Silvery scales or plaques
Explanation: ***Butterfly rash sparing the nasolabial folds*** - The patient's presentation with oral ulcers, sensitivity to light (photosensitivity), and a rash over the malar area **sparing the nasolabial folds** is highly characteristic of **Systemic Lupus Erythematosus (SLE)**, a condition where a butterfly rash is a hallmark. - This specific distribution of the malar rash is a key diagnostic feature differentiating it from other facial rashes. *Heliotrope rash on upper eyelid, bilateral hilar lymphadenopathy* - A **heliotrope rash** on the upper eyelids is characteristic of **dermatomyositis**, which also presents with muscle weakness, not typically oral ulcers or a malar rash. - **Bilateral hilar lymphadenopathy** is a classic finding in **sarcoidosis**, a granulomatous disease, not directly related to the patient's symptoms. *Port-wine stain, CNS malformations: seen in Sturge-Weber syndrome* - A **port-wine stain** (nevus flammeus) is a congenital capillary malformation, often on the face, and is a principal feature of **Sturge-Weber syndrome**, which involves CNS malformations and seizures. - This condition has no association with oral ulcers, photosensitivity, or the described malar rash. *Silvery scales or plaques: seen in psoriasis* - **Silvery scales or plaques** are the characteristic dermatological lesions of **psoriasis**, a chronic inflammatory skin condition. - Psoriasis typically presents with well-demarcated erythematous plaques and is not associated with oral ulcers, photosensitivity, or a lupus-specific malar rash.
Question 8: Cutis marmorata occurs due to exposure to –
- A. Cold temperature (Correct Answer)
- B. Dust
- C. Hot temperature
- D. Humidity
Explanation: ***Cold temperature*** - **Cutis marmorata** is a physiological response to **cold temperatures**, characterized by a mottled, reticulated vascular pattern on the skin. - This occurs due to **vasoconstriction** of the small arteries and arterioles, alongside **vasodilation** of the venules, creating the characteristic marbled appearance. *Dust* - Exposure to **dust** typically causes **irritation**, allergic reactions, or respiratory issues, such as **dermatitis**, **contact urticaria**, or **asthma**. - It does not directly lead to the characteristic vascular changes seen in cutis marmorata. *Hot temperature* - **Hot temperatures** generally cause **vasodilation** in the skin to facilitate **heat dissipation**, leading to redness and warmth. - This is the opposite physiological response to cutis marmorata, which involves vasoconstriction. *Humidity* - **Humidity** primarily affects **skin hydration** and the rate of perspiration, potentially exacerbating certain skin conditions like **eczema** or **fungal infections**. - High or low humidity does not directly induce the vascular changes that result in cutis marmorata.
Question 9: The mode of inheritance of Incontinentia pigmenti is:
- A. Autosomal dominant
- B. Autosomal recessive
- C. X-linked dominant (Correct Answer)
- D. X-linked recessive
Explanation: **Explanation:** **Incontinentia Pigmenti (Bloch-Sulzberger syndrome)** is a rare multisystem neurocutaneous disorder caused by a mutation in the **IKBKG gene** (formerly NEMO). 1. **Why X-linked Dominant is correct:** The inheritance is **X-linked dominant**. The mutation is typically **lethal in males** in utero, which is why the clinical phenotype is seen almost exclusively in females. Affected females survive due to functional mosaicism resulting from **X-chromosome inactivation (Lyonization)**. 2. **Why other options are wrong:** * **Autosomal Dominant/Recessive:** The gene is located on the X chromosome (Xq28), ruling out autosomal inheritance. * **X-linked Recessive:** In recessive conditions, heterozygous females are usually asymptomatic carriers. In IP, a single mutated allele is sufficient to cause the disease phenotype in females. **Clinical Phases (High-Yield for NEET-PG):** The skin lesions characteristically follow the **Lines of Blaschko** and evolve through four distinct stages: 1. **Vesicular stage:** Linear vesicles (present at birth or shortly after). 2. **Verrucous stage:** Hyperkeratotic, wart-like plaques. 3. **Hyperpigmented stage:** "Swirl-like" or "Marble cake" pigmentation (due to melanin incontinence into the dermis). 4. **Hypopigmented/Atrophic stage:** Linear streaks of hypopigmentation and hair loss. **Clinical Pearls:** * **Associated findings:** Peg-shaped (conical) teeth, delayed dentition, seizures, and cicatricial alopecia. * **Histology:** Eosinophilic spongiosis is a characteristic feature of the first stage. * **Key differentiator:** Unlike other X-linked dominant conditions, the male-to-female ratio is heavily skewed due to male lethality.
Question 10: A study of persons developing skin lesions following sun exposure is conducted. The lesions are not found on skin protected from ultraviolet light. Biopsies of involved skin show immunoglobulin G deposition along the dermal-epidermal junction, along with vacuolization of the basal layer and a perivascular lymphocytic infiltrate. No other organ involvement is present. Which of the following diseases do these patients most likely have?
- A. Bullous pemphigoid
- B. Celiac disease
- C. Discoid lupus erythematosus (Correct Answer)
- D. Dysplastic nevus syndrome
Explanation: ### Explanation The clinical presentation and histopathology described are classic for **Discoid Lupus Erythematosus (DLE)**, a form of Chronic Cutaneous Lupus Erythematosus (CCLE). **1. Why Discoid Lupus Erythematosus (DLE) is correct:** * **Photosensitivity:** DLE lesions are typically triggered or exacerbated by UV light and are confined to sun-exposed areas (face, scalp, ears). * **Histopathology:** The "vacuolization of the basal layer" (interface dermatitis) and "perivascular lymphocytic infiltrate" are hallmark features. * **Direct Immunofluorescence (DIF):** The "Lupus Band Test" shows a granular deposition of IgG and C3 along the dermal-epidermal junction (DEJ). In DLE, this is positive **only in involved (lesional) skin**, consistent with the question stating no other organ involvement (systemic lupus would often show deposition in uninvolved skin as well). **2. Why the other options are incorrect:** * **Bullous Pemphigoid:** While it shows IgG at the DEJ, it presents with subepidermal blisters and a linear (not granular) pattern. It is not typically induced by sun exposure. * **Celiac Disease:** This is associated with Dermatitis Herpetiformis, which presents with itchy vesicles on elbows/knees and shows **IgA** (not IgG) deposition in the dermal papillae. * **Dysplastic Nevus Syndrome:** This involves pigmented melanocytic lesions with architectural atypia, not an autoimmune inflammatory process with IgG deposition. **High-Yield Clinical Pearls for NEET-PG:** * **Lupus Band Test:** Positive in lesional skin in DLE; positive in both lesional and non-lesional skin in SLE. * **DLE Triad:** Erythema, adherent scales (carpet tack sign/follicular plugging), and atrophic scarring. * **Progression:** Only about 5-10% of patients with DLE progress to Systemic Lupus Erythematosus (SLE). * **Treatment:** Sun protection is the first step; topical corticosteroids or antimalarials (Hydroxychloroquine) are first-line medical therapies.
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