Pediatric Dermatology Practice Questions

Q: Which of the following is NOT a feature of Neurofibromatosis-1?

Ash leaf spots. **Explanation:** Neurofibromatosis Type 1 (NF-1), also known as von Recklinghausen disease, is an autosomal dominant neurocutaneous syndrome caused by a mutation in the *NF1* gene on chromosome 17. **Why "Ash leaf spots" is the correct answer:** Ash leaf spots (hypopigmented macules) are the earliest cutaneous sign of **Tuberous Sclerosis**, not NF-1. In NF-1, the characteristic pigmentary lesions are hyperpigmented, such as Café-au-lait macules. **Analysis of Incorrect Options:** * **Family History:** NF-1 has 100% penetrance. A first-degree relative with NF-1 is one of the seven formal NIH diagnostic criteria. * **Optic Glioma:** This is a specific central nervous system tumor (pilocytic astrocytoma) associated with NF-1 and is a major diagnostic criterion. * **Axillary Freckle:** Also known as **Crowe’s sign**, these are small hyperpigmented macules in the axillary or inguinal folds. It is a highly specific diagnostic feature of NF-1. **High-Yield Clinical Pearls for NEET-PG:** To diagnose NF-1, at least **two** of the following NIH criteria must be met: 1. **6+ Café-au-lait spots** (>5mm prepubertal, >15mm postpubertal). 2. **2+ Neurofibromas** or one plexiform neurofibroma. 3. **Axillary or inguinal freckling** (Crowe’s sign). 4. **Optic glioma**. 5. **2+ Lisch nodules** (iris hamartomas seen on slit-lamp exam). 6. **Distinctive bony lesions** (e.g., sphenoid dysplasia or thinning of long bone cortex). 7. **First-degree relative** with NF-1. *Mnemonic for Chromosome:* NF**1** is on Chromosome **17** (17 letters in Neurofibromatosis). NF**2** is on Chromosome **22**.

Q: A 6-year-old child is brought by his new foster mother who was concerned that when she brushed his teeth last night she noticed that his tongue was red in certain distinct patterns. He has otherwise not been ill. What is the most likely diagnosis?

Geographic tongue. **Explanation:** The correct diagnosis is **Geographic tongue** (Benign Migratory Glossitis). This condition is characterized by smooth, red, depapillated patches (loss of filiform papillae) surrounded by raised, grayish-white, serpentine borders. The "distinct patterns" mentioned in the question refer to the map-like appearance. Crucially, the lesions are dynamic—they heal in one area and migrate to another—and the patient is typically **asymptomatic** and otherwise healthy, as seen in this child. **Why the other options are incorrect:** * **Kawasaki disease:** While it presents with a "strawberry tongue," it is an acute systemic vasculitis. The child would be acutely ill with high-grade fever (≥5 days), conjunctivitis, rash, and lymphadenopathy. * **Pyogenic granuloma:** This is a solitary, vascular, pedunculated or sessile growth that often bleeds. it does not present as a "pattern" across the tongue. * **Hairy tongue:** This results from hypertrophy of filiform papillae, usually due to poor oral hygiene or tobacco use. It appears as a dark, furry discoloration (black or brown) on the dorsal surface, not red patches. **Clinical Pearls for NEET-PG:** * **Etiology:** Unknown, but associated with atopy, psoriasis, and stress. * **Histopathology:** Shows Munro’s microabscesses (neutrophils in the epithelium), similar to psoriasis. * **Management:** Reassurance is the mainstay as it is a benign, self-limiting condition. * **High-Yield Association:** Often seen in patients with a **fissured tongue**.

Q: A 17-year-old pregnant woman presents with scattered small, raised lesions on her trunk and axillary freckles. What is the most likely mode of inheritance for this condition?

Autosomal dominant. **Explanation:** The clinical presentation of **scattered small, raised lesions** (Neurofibromas) and **axillary freckling** (Crowe’s sign) is pathognomonic for **Neurofibromatosis Type 1 (NF1)**, also known as von Recklinghausen disease. **Why Autosomal Dominant is correct:** NF1 is an **Autosomal Dominant (AD)** disorder caused by a mutation in the *NF1* gene located on **chromosome 17q11.2**. This gene encodes **neurofibromin**, a tumor suppressor that regulates the Ras pathway. It exhibits 100% penetrance but highly variable expressivity. Notably, about 50% of cases arise from *de novo* mutations. **Why other options are incorrect:** * **Autosomal Recessive:** Very few neurocutaneous syndromes follow this pattern (e.g., Xeroderma Pigmentosum). NF1 requires only one mutated allele to manifest the phenotype. * **X-linked Dominant/Recessive:** NF1 affects males and females equally and shows male-to-male transmission, which rules out X-linked inheritance. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Criteria (NIH):** Requires 2 or more of: 1. ≥6 **Café-au-lait macules** (>5mm prepubertal, >15mm postpubertal). 2. ≥2 Neurofibromas or 1 Plexiform neurofibroma. 3. **Axillary or inguinal freckling** (Crowe’s sign). 4. **Lisch nodules** (iris hamartomas seen on slit-lamp exam). 5. Optic pathway glioma. 6. Distinctive osseous lesions (e.g., sphenoid dysplasia). 7. A first-degree relative with NF1. * **Pregnancy Connection:** Neurofibromas often increase in size or number during pregnancy due to hormonal changes. * **Chromosome 17:** Remember "Neurofibromatosis 17 letters = Chromosome 17."

Q: A child is diagnosed to have tuberous sclerosis. Which of the following skin lesions is not associated?

Xanthoderma. **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. It is characterized by the development of benign tumors (hamartomas) in multiple organs. **Why Xanthoderma is the correct answer:** **Xanthoderma** refers to a yellowish discoloration of the skin, most commonly caused by carotenemia (excessive intake of Vitamin A precursors) or jaundice. It has no pathogenic association with Tuberous Sclerosis. **Analysis of Incorrect Options (Associated Lesions):** * **Ash leaf spots (Hypomelanotic macules):** These are typically the **earliest** cutaneous sign of TSC. They appear as lanceolate, hypopigmented patches and are best visualized using a **Wood’s lamp**. * **Shagreen patches (Connective tissue nevi):** These are leathery, "orange-peel" textured plaques usually found on the lumbosacral region. They represent collagenomas. * **Adenoma sebaceum (Facial Angiofibromas):** Despite the historical name, these are not disorders of sebaceous glands but are **angiofibromas**. They typically appear in late childhood as malar, reddish papules in a butterfly distribution. **NEET-PG High-Yield Pearls:** 1. **Vogt’s Triad:** Epilepsy, Mental Retardation, and Adenoma Sebaceum (seen in only ~30% of cases). 2. **Koenen’s Tumor:** Periungual or subungual fibromas (usually appear after puberty). 3. **Confetti lesions:** Multiple tiny hypopigmented macules on the extremities; highly specific for TSC. 4. **Systemic findings:** Cardiac rhabdomyomas (often regress), Renal Angiomyolipomas (AML), and Cortical tubers/Subependymal nodules in the brain.

Q: In addition to neurofibromatosis, what other examination finding would you expect for this patient?

Lisch nodules. ***Lisch nodules*** - **Lisch nodules** are **iris hamartomas** that appear as well-defined, dome-shaped, tan to brown nodules on the iris surface, present in over **90% of adults** with **neurofibromatosis type 1 (NF1)**. - These **benign melanocytic hamartomas** are pathognomonic for **NF1** and increase in number with age, making them a key diagnostic criterion for the condition. *Aortic regurgitation* - **Aortic regurgitation** is not a recognized feature of **neurofibromatosis type 1** and would suggest other conditions like **bicuspid aortic valve** or **rheumatic heart disease**. - **NF1** primarily affects the **nervous system**, **skin**, and **bones**, not typically causing significant **cardiac valve abnormalities**. *Chvostek sign* - **Chvostek sign** is a clinical sign of **hypocalcemia** where tapping the **facial nerve** causes **facial muscle twitching**, unrelated to **neurofibromatosis**. - This sign indicates **neuromuscular irritability** due to **low calcium levels** and has no association with the **genetic mutations** seen in **NF1**. *Thyroid bruit* - **Thyroid bruit** is associated with **hyperthyroidism** (especially **Graves' disease**) due to increased **thyroid vascularity** and blood flow. - **Neurofibromatosis type 1** does not typically cause **thyroid dysfunction** or **thyroid enlargement** that would produce an audible bruit.

Q: Which condition is characterized by the following lesion?

Neurofibromatosis type 1 (NF1). ***Neurofibromatosis type 1 (NF1)*** • Characterized by **café-au-lait macules** (light brown spots) and **cutaneous neurofibromas** as hallmark skin lesions that help establish the diagnosis. • Additional features include **axillary/inguinal freckling** and **Lisch nodules** (iris hamartomas), making skin findings central to NF1 diagnosis. *Neurofibromatosis type 2 (NF2)* • Primarily presents with **bilateral vestibular schwannomas** causing hearing loss, with minimal to no characteristic skin lesions. • Skin manifestations are rare and not diagnostic features, unlike the prominent cutaneous findings in NF1. *Tuberous sclerosis* • Characterized by distinctive skin lesions including **ash-leaf macules** (hypopigmented spots), **shagreen patches** (leathery plaques), and **adenoma sebaceum** (facial angiofibromas). • These lesions are morphologically different from the café-au-lait spots and neurofibromas seen in NF1. *Von Hippel-Lindau disease (VHL)* • Primarily affects internal organs with **retinal hemangioblastomas**, **cerebellar hemangioblastomas**, and **renal cell carcinomas**. • Does not have characteristic primary skin lesions as a diagnostic feature, unlike the other neurocutaneous syndromes.

Q: Spontaneous regression can occur with which of the following conditions?

Strawberry angioma. **Explanation:** The correct answer is **Strawberry angioma** (also known as Infantile Hemangioma). **1. Why Strawberry Angioma is correct:** Strawberry angiomas are the most common benign tumors of infancy. They follow a classic triphasic clinical course: * **Proliferation Phase:** Rapid growth during the first 6–12 months of life. * **Quiescent Phase:** Growth stabilizes. * **Involution Phase:** **Spontaneous regression** occurs over several years. A useful clinical "rule of thumb" is that 50% resolve by age 5, 70% by age 7, and 90% by age 9. Because of this natural history, most cases require only observation ("masterly inactivity") unless they obstruct vision or the airway. **2. Why the other options are incorrect:** * **Cavernous hemangioma:** Unlike strawberry angiomas (which are capillary), cavernous hemangiomas involve deeper, larger vascular channels. They are usually permanent and **do not undergo spontaneous regression**; they may even enlarge over time. * **Nevus flammeus (Port-wine stain):** This is a capillary malformation present at birth. It is **permanent** and does not regress. In fact, it tends to grow proportionately with the child, may darken (to a deep purple), and can become thickened or nodular in adulthood. **Clinical Pearls for NEET-PG:** * **Kasabach-Merritt Syndrome:** A high-yield complication where a rapidly growing vascular tumor (usually tufted angioma or kaposiform hemangioendothelioma) causes consumptive coagulopathy and thrombocytopenia. * **PHACE Syndrome:** Associated with large facial infantile hemangiomas (Posterior fossa malformations, Hemangiomas, Arterial anomalies, Cardiac defects, Eye anomalies). * **Treatment:** If treatment is required (e.g., for visual obstruction), **Propranolol** (oral beta-blocker) is now the first-line medical therapy, replacing systemic corticosteroids.

Q: A 10-year-old child has violaceous papules and pterygium of the nails. What is the most likely diagnosis?

Lichen Planus. ### **Explanation** The correct answer is **Lichen Planus (LP)**. **1. Why Lichen Planus is correct:** Lichen Planus is a chronic inflammatory condition characterized by the "6 Ps": **P**lanar (flat-topped), **P**urple (violaceous), **P**olygonal, **P**ruritic, **P**apules, and **P**laques. Nail involvement occurs in about 10% of cases. The most characteristic (pathognomonic) nail finding in LP is **Dorsal Pterygium** (V-shaped extension of the proximal nail fold onto the nail bed), which occurs due to scarring of the nail matrix. **2. Why other options are incorrect:** * **Psoriasis:** While it commonly affects nails, the classic findings are **pitting** (deep and irregular), **oil spots** (salmon patches), and subungual hyperkeratosis. It does not cause pterygium. * **Pemphigus/Pemphigoid:** These are autoimmune blistering (bullous) disorders. While they can occasionally cause nail dystrophy due to periungual inflammation, they present primarily with blisters/erosions and do not typically manifest with violaceous papules or pterygium. **3. NEET-PG High-Yield Pearls:** * **Wickham Striae:** Fine white reticular lines seen on the surface of LP papules (best seen with oil immersion). * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Psoriasis and Vitiligo). * **Civatte Bodies:** Histopathological hallmark representing apoptotic keratinocytes in the basal layer. * **Nail LP:** Can lead to "Twenty-nail dystrophy" (trachyonychia) in children. * **Treatment:** Topical or systemic corticosteroids are the first-line management.

Q: An asymptomatic 3-year-old child presents with acute onset right cheek swelling that is erythematous but not warm to touch. On palpation, mildly tender, discrete, indurated masses are appreciated. What is the most likely cause of this presentation?

Panniculitis. **Explanation:** The clinical presentation describes **Popsicle Panniculitis**, a form of cold-induced subcutaneous fat necrosis. In young children, the high concentration of saturated fats in subcutaneous tissue makes it susceptible to crystallization and inflammation when exposed to cold (e.g., sucking on a popsicle or ice cube). **1. Why Panniculitis is correct:** The hallmark of this condition is the **acute onset** of erythematous, indurated, and mildly tender nodules or plaques, typically located on the cheeks (near the corners of the mouth). The key diagnostic clue is that the area is **not warm to touch**, distinguishing it from infectious processes. It is a self-limiting condition that resolves spontaneously within weeks. **2. Why other options are incorrect:** * **Erysipelas & Cellulitis:** These are bacterial infections (usually *S. pyogenes* or *S. aureus*). They present with "calor" (warmth) and systemic symptoms like fever. The absence of warmth and the child being asymptomatic (afebrile) makes an infectious etiology unlikely. * **Trauma:** While trauma can cause swelling, it usually presents with ecchymosis (bruising) and significant tenderness rather than discrete, indurated masses. **Clinical Pearls for NEET-PG:** * **Target Population:** Most common in infants and toddlers due to higher **saturated-to-unsaturated fat ratios**. * **Differential Diagnosis:** Must be distinguished from **Facial Cellulitis** (which is warm, painful, and often associated with fever). * **Management:** Reassurance only; no active treatment is required as it is a benign, self-resolving condition. * **Other Cold Panniculitis:** Can also occur on the thighs of equestrians ("Equestrian Panniculitis") due to cold weather and tight clothing.

Q: Neonatal fat necrosis (subcutaneous fat necrosis of the newborn) resembles which of the following conditions?

Post-steroidal panniculitis. **Explanation:** **Subcutaneous Fat Necrosis of the Newborn (SCFN)** is a transient form of panniculitis occurring in full-term or post-term neonates, often following birth asphyxia, hypothermia, or trauma. **Why Post-steroidal Panniculitis is the correct answer:** Both SCFN and post-steroidal panniculitis share identical histopathological features. They are characterized by a **lobular panniculitis** with a pathognomonic finding: **needle-shaped clefts** arranged in a **radial (sunburst) pattern** within adipocytes. These clefts represent dissolved triglyceride crystals. Clinically, post-steroidal panniculitis occurs in children after the rapid withdrawal of high-dose systemic corticosteroids, mirroring the firm, erythematous nodules seen in SCFN. **Analysis of Incorrect Options:** * **A. Erythema Induratum (Bazin Disease):** This is a chronic lobular panniculitis associated with tuberculosis, typically presenting as nodules on the posterior calves of adult women. It shows granulomatous inflammation and vasculitis, unlike SCFN. * **C. Lupus Panniculitis:** This presents as deep-seated nodules (Lupus profundus) in adults with SLE or DLE. Histology shows hyaline sclerosis of fat and lymphoid follicles, which is distinct from the crystal formation in SCFN. * **D. Lipodermatosclerosis:** This is a localized chronic fibrosing panniculitis of the lower legs resulting from venous insufficiency ("inverted champagne bottle" appearance). It is not seen in neonates. **High-Yield Clinical Pearls for NEET-PG:** * **Most serious complication of SCFN:** **Hypercalcemia** (occurs 1–6 months after skin lesions appear; monitor serum calcium levels). * **Histology Keyword:** "Radial arrangement of needle-shaped clefts." * **Risk Factors:** Meconium aspiration, therapeutic hypothermia, and obstetric trauma. * **Prognosis:** Usually self-limiting, but requires monitoring for hypercalcemia to prevent nephrocalcinosis.

Question 1

Which of the following is NOT a feature of Neurofibromatosis-1?

Accepted Answer

Ash leaf spots

Answer

Family history

Answer

Optic glioma

Answer

Axillary freckle

Question 2

A 6-year-old child is brought by his new foster mother who was concerned that when she brushed his teeth last night she noticed that his tongue was red in certain distinct patterns. He has otherwise not been ill. What is the most likely diagnosis?

Accepted Answer

Geographic tongue

Answer

Kawasaki disease

Answer

Pyogenic granuloma of the tongue

Answer

Hairy tongue

Question 3

A 17-year-old pregnant woman presents with scattered small, raised lesions on her trunk and axillary freckles. What is the most likely mode of inheritance for this condition?

Accepted Answer

Autosomal dominant

Answer

Autosomal recessive

Answer

X-linked dominant

Answer

X-linked recessive

Question 4

A child is diagnosed to have tuberous sclerosis. Which of the following skin lesions is not associated?

Accepted Answer

Xanthoderma

Answer

Ash leaf spot

Answer

Shagreen patches

Answer

Adenoma sebaceum

Question 5

In addition to neurofibromatosis, what other examination finding would you expect for this patient?

Accepted Answer

Lisch nodules

Answer

Aortic regurgitation

Answer

Chvostek sign

Answer

Thyroid bruit

Question 6

Which condition is characterized by the following lesion?

Accepted Answer

Neurofibromatosis type 1 (NF1)

Answer

Neurofibromatosis type 2 (NF2)

Answer

Tuberous sclerosis

Answer

Von Hippel-Lindau disease (VHL)

Question 7

Spontaneous regression can occur with which of the following conditions?

Accepted Answer

Strawberry angioma

Answer

Cavernous hemangioma

Answer

Nevus flammeus

Answer

None of the above

Question 8

A 10-year-old child has violaceous papules and pterygium of the nails. What is the most likely diagnosis?

Accepted Answer

Lichen Planus

Answer

Psoriasis

Answer

Pemphigus

Answer

Pemphigoid

Question 9

An asymptomatic 3-year-old child presents with acute onset right cheek swelling that is erythematous but not warm to touch. On palpation, mildly tender, discrete, indurated masses are appreciated. What is the most likely cause of this presentation?

Accepted Answer

Panniculitis

Answer

Erysipelas

Answer

Cellulitis

Answer

Trauma

Question 10

Neonatal fat necrosis (subcutaneous fat necrosis of the newborn) resembles which of the following conditions?

Accepted Answer

Post-steroidal panniculitis

Answer

Erythema induratum

Answer

Lupus panniculitis

Answer

Lipodermatosclerosis

Pediatric Dermatology — MCQs

Pediatric Dermatology — MCQs

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