Pediatric Dermatology Practice Questions

Q: Which of the following conditions produces seborrheic dermatitis-like lesions in an infant?

Langerhan cell histiocytosis. **Explanation:** **Langerhans Cell Histiocytosis (LCH)** is the correct answer because it frequently presents in infants as a "cradle cap" mimic. The underlying pathology involves the neoplastic proliferation of Langerhans cells. Clinically, it manifests as scaly, erythematous, or purpuric papules and plaques, primarily affecting the scalp, retroauricular areas, and intertriginous folds. Unlike simple seborrheic dermatitis, LCH lesions are often **hemorrhagic (petechial)**, may show ulceration, and are typically refractory to standard antifungal or steroid treatments. **Analysis of Incorrect Options:** * **Juvenile Xanthogranuloma (JXG):** This is the most common form of non-Langerhans cell histiocytosis. It typically presents as solitary, firm, yellowish-orange "dome-shaped" nodules, not as a diffuse seborrheic-like rash. * **Multicentric Histiocytosis:** A rare systemic disease characterized by destructive arthritis and skin nodules (papulonodular eruption), usually seen in adults rather than infants. * **Erdheim-Chester Disease:** A rare non-Langerhans cell histiocytosis that primarily affects adults. It is characterized by xanthomatous infiltration of internal organs and long bone osteosclerosis, not pediatric dermatitis. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Hallmark:** On Electron Microscopy, LCH shows **Birbeck granules** (tennis-racket shaped). * **Immunohistochemistry (IHC):** LCH cells are positive for **CD1a, S100, and CD207 (Langerin)**. * **Red Flag:** If an infant has "seborrheic dermatitis" that is **petechial/purpuric** or associated with **atrophy/ulceration**, always rule out LCH with a skin biopsy. * **Letterer-Siwe Disease:** The specific clinical subtype of LCH in infants that presents with this multisystem, seborrheic-like distribution.

Q: Which of the following is a characteristic skin lesion of Tuberous sclerosis?

Adenoma sebaceum. **Explanation:** Tuberous Sclerosis Complex (TSC) 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 Adenoma Sebaceum is the correct answer:** Despite the name, **Adenoma sebaceum** is a misnomer; these lesions are actually **angiofibromas**. They typically appear as firm, reddish-pink papules in a malar distribution (butterfly area of the face), sparing the upper lip. They are considered a pathognomonic cutaneous marker for TSC, appearing in about 75% of patients, usually during childhood. **Analysis of other options:** * **Periungual fibroma (Koenen tumors):** While these are also characteristic of TSC, they usually appear later (during puberty) and are less frequent than facial angiofibromas. In the context of "characteristic" lesions, Adenoma sebaceum is the classic textbook answer. * **Hypopigmented macules (Ash-leaf spots):** These are often the **earliest** sign of TSC, visible under Wood’s lamp. However, they are less specific than angiofibromas, as isolated hypopigmented macules can occur in the general population. * **Haemangioma:** These are vascular proliferations not typically associated with Tuberous Sclerosis (more common in syndromes like Sturge-Weber). **High-Yield Clinical Pearls for NEET-PG:** * **Vogt’s Triad:** Epilepsy, Mental Retardation, and Adenoma Sebaceum (seen in only 30% of cases). * **Shagreen Patch:** A connective tissue nevus (leathery plaque) usually found on the lumbosacral area. * **Confetti lesions:** Multiple tiny hypopigmented macules on the extremities. * **Systemic findings:** Renal Angiomyolipomas, Cardiac Rhabdomyomas, and Subependymal Giant Cell Astrocytomas (SEGA).

Q: What is the earliest presenting feature of tuberous sclerosis?

Ash leaf spot. **Explanation:** **Tuberous Sclerosis Complex (TSC)** is an autosomal dominant neurocutaneous syndrome characterized by the development of benign tumors (hamartomas) in multiple organs. **Why Ash Leaf Spot is correct:** The **Ash leaf spot** (hypomelanotic macule) is the **earliest clinical sign** of Tuberous Sclerosis. These macules are often present at birth or appear in early infancy (usually before age 2). They are best visualized using a **Wood’s lamp**, which highlights the contrast between the hypopigmented area and normal skin. At least three such macules are required to meet the major diagnostic criteria. **Analysis of Incorrect Options:** * **Facial Angiofibromas (Adenoma Sebaceum):** These typically appear later in childhood, usually between **2 to 5 years of age**. They are malar distributions of pink-to-red papules. * **Shagreen Patch:** These are connective tissue nevi (leathery plaques) usually found on the lower back. They typically appear between **2 to 6 years of age**. * **Gingival Fibroma:** These are oral manifestations that generally appear in **late childhood or adolescence**, much later than the initial cutaneous markers. **NEET-PG High-Yield Pearls:** * **Vogt’s Triad:** Epilepsy, Mental Retardation, and Adenoma Sebaceum (only seen in ~30% of patients). * **Confetti Lesions:** Multiple tiny hypopigmented macules; these are highly specific for TSC. * **Koenen’s Tumor:** Periungual fibromas appearing around puberty; they are a major diagnostic criterion. * **Genetics:** Mutation in **TSC1 (Hamartin)** on chromosome 9 or **TSC2 (Tuberin)** on chromosome 16.

Q: Which of the following skin lesions does not change or remains the same throughout life?

Portwine stain. **Explanation:** The correct answer is **Port-wine stain (PWS)**. The fundamental medical concept here is the distinction between **vascular malformations** and **vascular tumors**. 1. **Why Port-wine Stain is correct:** A Port-wine stain (Nevus Flammeus) is a **capillary malformation** present at birth. Unlike hemangiomas, it is composed of mature, dilated dermal capillaries. It follows the rule of "permanent and progressive": it does not involute, grows proportionately with the child, and often becomes darker, thicker, or more nodular (verrucous) in adulthood. It is a permanent lesion that persists throughout life unless treated with lasers (e.g., Pulsed Dye Laser). 2. **Why the other options are incorrect:** * **Salmon Patch (Nevus Simplex):** Also known as "Stork bites" or "Angel kisses," these are transient capillary ectasias. Most fade and disappear spontaneously within the first 1–2 years of life. * **Strawberry Angioma / Capillary Hemangioma:** These are **vascular tumors** (Infantile Hemangiomas). They typically follow a predictable life cycle: a rapid proliferative phase after birth, followed by a slow spontaneous involution phase. Approximately 50% disappear by age 5, and 90% by age 9. **High-Yield Clinical Pearls for NEET-PG:** * **Sturge-Weber Syndrome:** A PWS in the V1/V2 distribution of the trigeminal nerve may be associated with glaucoma and leptomeningeal angiomatosis (look for "tram-track" calcifications on CT). * **Klippel-Trenaunay Syndrome:** PWS associated with limb hypertrophy and venous malformations. * **Treatment of Choice:** The **Pulsed Dye Laser (585 or 595 nm)** is the gold standard for treating Port-wine stains. * **Mnemonic:** Malformations (PWS) are **Permanent**; Hemangiomas (Strawberry) **Halt and Heal**.

Q: Which of the following statements is NOT true about Sturge-Weber syndrome?

Intracranial hamartoma. **Explanation:** Sturge-Weber Syndrome (SWS), also known as encephalotrigeminal angiomatosis, is a neurocutaneous disorder characterized by a sporadic mutation in the **GNAQ gene**. It is defined by the triad of a facial capillary malformation, leptomeningeal angiomas, and ocular involvement. **Why Option D is correct:** The characteristic intracranial lesion in SWS is a **leptomeningeal angioma** (a vascular malformation of the pia mater), not a hamartoma. Intracranial hamartomas (such as cortical tubers or subependymal nodules) are hallmark features of **Tuberous Sclerosis**, not Sturge-Weber Syndrome. **Analysis of incorrect options:** * **A. Port-wine stain (Nevus Flammeus):** This is the most common clinical sign, typically presenting in the distribution of the trigeminal nerve (V1 and V2 branches). * **B. Calcification in the brain:** Chronic ischemia due to leptomeningeal angiomas leads to cortical calcification. On imaging (CT scan), these appear as classic **"tram-track" calcifications**. * **C. Cortical atrophy:** Reduced blood flow and recurrent seizures lead to progressive neuronal loss and atrophy of the underlying cerebral cortex, usually ipsilateral to the facial lesion. **NEET-PG High-Yield Pearls:** * **Inheritance:** Sporadic (not hereditary). * **Radiology:** "Tram-track" calcifications on CT; "pial enhancement" on MRI with gadolinium. * **Ocular finding:** Glaucoma is the most common ocular manifestation (buphthalmos may occur). * **Clinical Presentation:** Port-wine stain + Contralateral hemiparesis + Seizures + Intellectual disability.

Q: These lesions are seen in which condition?

Neurofibromatosis type 1 (NF1). ***Neurofibromatosis type 1 (NF1)*** - **Café-au-lait macules** (≥6 spots >5mm in prepubertal children or >15mm in adults) are pathognomonic for NF1 and form part of the diagnostic criteria. - These lesions appear as **flat, light brown patches** with smooth borders and are often the first manifestation of NF1 in childhood. *Tuberous sclerosis* - Characterized by **ash-leaf spots** (hypopigmented macules) and **shagreen patches** (leathery plaques), not café-au-lait macules. - Also presents with **adenoma sebaceum** (facial angiofibromas) and **periungual fibromas** around nails. *Sturge-Weber syndrome* - Primary cutaneous manifestation is a **port-wine stain** (capillary malformation) typically in the **trigeminal nerve distribution**. - The lesion is a **vascular malformation** that appears as a flat, pink-to-red birthmark, not pigmented macules. *Von Hippel-Lindau syndrome* - Primarily presents with **retinal angiomas** and **cerebellar hemangioblastomas** rather than distinctive skin lesions. - May have **café-au-lait spots** occasionally, but they are not a defining feature and occur much less frequently than in NF1.

Q: All of the following are true about dyskeratosis congenita, EXCEPT:

Cutaneous depigmentation. ### Explanation **Dyskeratosis Congenita (DKC)** is a rare inherited bone marrow failure syndrome characterized by the classic **clinical triad**: 1. **Nail dystrophy** (ridged, split, or absent nails) 2. **Oral leukoplakia** (white patches on the tongue/mucosa) 3. **Reticular skin hyperpigmentation** (typically in a "lace-like" pattern on the neck and chest) **Why Option A is the Correct Answer:** The cutaneous manifestation of DKC is **hyperpigmentation**, not depigmentation. The skin changes usually appear in the first decade of life and are characterized by a dusky, reticular (net-like) pattern of increased melanin deposition. **Analysis of Other Options:** * **Option B (Leukoplakia):** This is a hallmark of the classic triad. It carries a high risk of malignant transformation into squamous cell carcinoma. * **Option C (Nail Dystrophy):** This is often the earliest sign of the triad, appearing in early childhood. * **Option D (Shortened telomere length):** DKC is fundamentally a **"telomeropathy."** It is caused by mutations in genes responsible for telomere maintenance (e.g., *DKC1, TERC, TERT*). Measuring telomere length in peripheral blood leukocytes via Flow-FISH is the gold-standard diagnostic test. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Most commonly X-linked recessive (*DKC1* gene encoding **dyskerin**), but autosomal dominant and recessive forms exist. * **Primary Cause of Death:** Bone marrow failure (aplastic anemia) occurs in ~80% of patients. * **Cancer Risk:** Significant predisposition to Head and Neck Squamous Cell Carcinoma (HNSCC) and Myelodysplastic Syndrome (MDS). * **Hoyeraal-Hreidarsson Syndrome:** A severe variant of DKC characterized by cerebellar hypoplasia and immunodeficiency.

Q: Which of the following is not a vascular malformation?

Infantile haemangioma. **Explanation:** The fundamental distinction in vascular dermatology lies between **Vascular Tumors** and **Vascular Malformations** (ISSVA Classification). **1. Why Infantile Haemangioma (Option A) is the correct answer:** Infantile haemangioma is a **vascular tumor**, not a malformation. It is characterized by cellular proliferation (hyperplasia of endothelial cells). Clinically, it follows a predictable life cycle: it is usually absent at birth, undergoes a rapid **proliferative phase** during infancy, followed by slow **involution** over several years. It is typically **GLUT-1 positive** on immunohistochemistry. **2. Why the other options are Vascular Malformations:** Vascular malformations are structural abnormalities present at birth (though they may become visible later). They grow proportionately with the child and do not involute. * **Salmon Patch (Option B):** A common capillary malformation (nevus simplex) often found on the nape of the neck ("stork bite") or eyelids ("angel’s kiss"). * **Port Wine Stain (Option C):** A permanent capillary malformation (nevus flammeus) that darkens and thickens over time; it is associated with Sturge-Weber Syndrome. * **Naevus Anaemicus (Option D):** A localized vascular anomaly where the blood vessels have increased sensitivity to catecholamines, leading to permanent vasoconstriction (appearing as a pale patch). **High-Yield Clinical Pearls for NEET-PG:** * **GLUT-1 Marker:** The most specific marker to differentiate Infantile Haemangioma (+ve) from vascular malformations (-ve). * **Treatment of Choice:** Oral **Propranolol** is the first-line treatment for complicated infantile haemangiomas. * **Kasabach-Merritt Phenomenon:** Associated with Tufted Angioma or Kaposiform Hemangioendothelioma, **not** with common infantile haemangioma. * **Pulsed Dye Laser (PDL):** The gold standard treatment for Port Wine Stains.

Question 1

Which of the following conditions produces seborrheic dermatitis-like lesions in an infant?

Accepted Answer

Langerhan cell histiocytosis

Answer

Juvenile xanthogranuloma

Answer

Multicentric histiocytosis

Answer

Erdheim Chester disease

Question 2

Which of the following is a characteristic skin lesion of Tuberous sclerosis?

Accepted Answer

Adenoma sebaceum

Answer

Haemangioma

Answer

Periungual fibroma

Answer

Hypopigmented macules

Question 3

What is the earliest presenting feature of tuberous sclerosis?

Accepted Answer

Ash leaf spot

Answer

Facial angiofibroma

Answer

Shagreen patch

Answer

Gingival fibroma

Question 4

Which of the following skin lesions does not change or remains the same throughout life?

Accepted Answer

Portwine stain

Answer

Salmon patch

Answer

Strawberry angiomas

Answer

Capillary hemangiomas

Question 5

Which of the following statements is NOT true about Sturge-Weber syndrome?

Accepted Answer

Intracranial hamartoma

Answer

Port-wine stain

Answer

Calcification in the brain

Answer

Cortical atrophy

Question 6

These lesions are seen in which condition?

Accepted Answer

Neurofibromatosis type 1 (NF1)

Answer

Tuberous sclerosis

Answer

Sturge-Weber syndrome

Answer

Von Hippel-Lindau syndrome

Question 7

All of the following are true about dyskeratosis congenita, EXCEPT:

Accepted Answer

Cutaneous depigmentation

Answer

Leukoplakia

Answer

Nail dystrophy

Answer

Shortened telomere length in leukocytes

Question 8

A 10-year-old boy presents with multiple tan-colored patches on his skin and freckle-like changes in his axillary area. The remainder of his clinical examination is normal. Which of the following conditions is also found in patients with this disorder as they age?

Accepted Answer

Multiple cutaneous and subcutaneous tumors

Answer

Bilateral eighth nerve tumors

Answer

Irregular small pupils

Answer

Cataracts

Question 9

Which of the following is not a vascular malformation?

Accepted Answer

Infantile haemangioma

Answer

Salmon patch

Answer

Port wine stain

Answer

Naevus aneamicus

Question 10

Which of the following is NOT included under the diagnostic criteria for Neurofibromatosis type 1?

Accepted Answer

Cafe-au-lait macules

Answer

Optic glioma

Answer

Periungual fibroma

Answer

Sphenoid dysplasia

Pediatric Dermatology — MCQs

Pediatric Dermatology — MCQs

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