Pediatric Dermatology Practice Questions

Q: What are the common sites for a Mongolian spot?

Lumbo-sacral area. **Explanation:** **Mongolian Spot** (Dermal Melanocytosis) is a common, benign, congenital birthmark. It occurs due to the **arrest of melanocytes** during their migration from the neural crest to the epidermis. These melanocytes remain trapped in the deeper **dermis**, and their blue-gray appearance is a result of the **Tyndall effect** (shorter wavelengths of light are scattered by dermal melanin). * **Why C is correct:** The **lumbo-sacral area** and buttocks are the most common sites, occurring in over 90% of affected infants, particularly those of Asian, African, and Hispanic descent. * **Why A, B, and D are incorrect:** While "Extrasacral Mongolian spots" can occur on the face, neck, or extremities, these are significantly less common. The lumbo-sacral region remains the classic and most frequent anatomical site. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Appearance:** Flat, non-blanchable, blue-gray or slate-colored macules/patches with indefinite borders. * **Prognosis:** Most spots fade spontaneously by age 2–6 years and usually disappear by puberty. No treatment is required. * **Differential Diagnosis:** It is crucial to document these at birth to avoid confusion with **child abuse (bruising)**. Unlike bruises, Mongolian spots do not change color over days or show tenderness. * **Associations:** Extensive or persistent Mongolian spots may rarely be associated with inborn errors of metabolism, such as **GM1 gangliosidosis** or **Hurler syndrome**.

Q: Koenen's periungual fibromas are seen in > 50% of cases with which condition?

Tuberous sclerosis. **Explanation:** **Koenen’s tumors (Periungual fibromas)** are smooth, flesh-colored, or reddish papules or nodules that arise from the nail fold. They are a pathognomonic cutaneous marker for **Tuberous Sclerosis Complex (TSC)**, an autosomal dominant neurocutaneous syndrome caused by mutations in the *TSC1* (hamartin) or *TSC2* (tuberin) genes. While they typically appear during adolescence or early adulthood, they are present in over 50% of adult patients with TSC and represent one of the major clinical criteria for diagnosis. **Analysis of Options:** * **Tuberous Sclerosis (Correct):** Characterized by the triad of seizures, mental retardation, and adenoma sebaceum (Vogt’s triad). Koenen’s tumors are specific to this condition. * **Sturge-Weber Syndrome:** A phakomatosis characterized by a Port-wine stain (Nevus flammeus) in the V1/V2 distribution of the trigeminal nerve, glaucoma, and leptomeningeal angiomas. It does not feature periungual fibromas. * **Ataxia Telangiectasia:** An autosomal recessive disorder presenting with cerebellar ataxia, oculocutaneous telangiectasia, and immunodeficiency. * **Neurofibromatosis (NF-1):** Characterized by Café-au-lait macules, Lisch nodules, and neurofibromas. While it involves cutaneous tumors, periungual fibromas are not a feature. **High-Yield Clinical Pearls for TSC:** 1. **Ash-leaf spots:** Earliest cutaneous sign (hypopigmented macules best seen under Wood’s lamp). 2. **Adenoma Sebaceum:** Actually **facial angiofibromas**, typically found in a butterfly distribution on the face. 3. **Shagreen patch:** Connective tissue nevus usually located on the lower back. 4. **Confetti lesions:** Multiple tiny hypopigmented macules on the limbs. 5. **Internal findings:** Cardiac rhabdomyomas (often regress), Renal Angiomyolipomas (AML), and Subependymal Giant Cell Astrocytomas (SEGA).

Q: A patient presents with seizures, adenoma sebaceum, and mental retardation. What is the diagnosis?

Tuberous sclerosis. **Explanation:** The patient presents with the classic **Vogt’s Triad**: Seizures, Mental Retardation, and Adenoma Sebaceum (facial angiofibromas). This triad is pathognomonic for **Tuberous Sclerosis Complex (TSC)**, an autosomal dominant neurocutaneous syndrome caused by mutations in the *TSC1* (Hamartin) or *TSC2* (Tuberin) genes. **Why the correct answer is right:** * **Adenoma Sebaceum:** Despite the name, these are actually **facial angiofibromas** (hamartomas of vascular and connective tissue) typically found in the malar region. * **Neurological involvement:** Cortical tubers and subependymal nodules lead to refractory seizures and cognitive impairment. **Why incorrect options are wrong:** * **Sturge-Weber Syndrome:** Characterized by a Port-wine stain (Nevus Flammeus) in the V1/V2 distribution, glaucoma, and leptomeningeal angiomas. It does not feature adenoma sebaceum. * **Neurofibromatosis (Type 1):** Presents with Café-au-lait spots, Lisch nodules, and neurofibromas. While seizures can occur, the cutaneous markers are distinct from TSC. * **Neurocysticercosis:** A parasitic infection causing seizures and ring-enhancing lesions on imaging, but it lacks the genetic cutaneous markers like adenoma sebaceum. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign:** Ash-leaf spots (hypopigmented macules), best seen under **Wood’s lamp**. * **Pathognomonic skin finding:** Shagreen patch (connective tissue nevus on the lower back). * **Ungual findings:** Koenen tumors (periungual fibromas). * **Systemic associations:** Renal Angiomyolipoma (most common renal lesion) and Cardiac Rhabdomyoma (often regresses spontaneously).

Q: What is the recommended treatment for a child presenting with an erythematous, non-blanching, bosselated lesion on the right side of the face?

Flash light pumped dye laser. ### **Explanation** The clinical description—an **erythematous, non-blanching, bosselated lesion** on the face—is characteristic of a **Port-Wine Stain (PWS)** or **Capillary Malformation**. These are congenital vascular malformations composed of dilated capillaries in the dermis. **1. Why Flashlamp-Pumped Pulsed Dye Laser (FPDL) is correct:** The **Pulsed Dye Laser (585 or 595 nm)** is the **gold standard** treatment for Port-Wine Stains. It operates on the principle of **selective photothermolysis**. The wavelength is specifically absorbed by oxyhemoglobin (the target chromophore) within the blood vessels. The "pulsed" delivery ensures that the thermal energy is confined to the vessel wall, destroying it without damaging the surrounding collagen, thereby minimizing the risk of scarring. **2. Why the other options are incorrect:** * **Erbium:YAG Laser (2940 nm):** This is an ablative resurfacing laser targeting water. It is used for skin rejuvenation or removing superficial epidermal lesions, not for deep vascular malformations. * **Nd:YAG Laser (1064 nm):** While it can penetrate deeper, it has a higher risk of scarring and is generally reserved for thicker, hypertrophic, or resistant vascular lesions rather than first-line treatment of pediatric PWS. * **Q-switched Ruby Laser (694 nm):** This laser targets melanin and is primarily used for pigmented lesions (like Nevus of Ota) or tattoo removal. **Clinical Pearls for NEET-PG:** * **Sturge-Weber Syndrome:** Always rule this out if a PWS involves the V1/V2 distribution of the trigeminal nerve (look for glaucoma and leptomeningeal angiomas). * **Progression:** Unlike hemangiomas, PWS **do not involute**; they grow proportionately with the child and may become darker and "bosselated" (bumpy) over time. * **Early Intervention:** Treatment with FPDL is most effective when started in infancy due to thinner skin and smaller vessel diameter.

Q: A 1 and 1/2 year old child with a history of chronic diarrhea presents with perioral and perineal rash. What is your diagnosis?

Acrodermatitis enteropathica. ### Explanation **Correct Answer: C. Acrodermatitis enteropathica** **Mechanism and Clinical Presentation:** Acrodermatitis enteropathica (AE) is an autosomal recessive disorder caused by a mutation in the **SLC39A4 gene**, which encodes a zinc transporter protein. This leads to severe **zinc deficiency**. The classic clinical triad includes: 1. **Dermatitis:** Vesiculobullous or eczematous lesions specifically in **perioral, acral (extremities), and perineal/diaper areas**. 2. **Alopecia.** 3. **Diarrhea.** Symptoms typically manifest in infancy, often shortly after weaning from breast milk to cow's milk (as breast milk contains a zinc-binding ligand that aids absorption). **Why Incorrect Options are Wrong:** * **A. Epidermolysis bullosa:** A genetic mechanobullous disorder characterized by skin fragility and blistering in response to minor trauma. It does not typically present with chronic diarrhea. * **B. Staphylococcal scalded skin syndrome (SSSS):** Caused by *Staph. aureus* exfoliative toxins. It presents with diffuse erythema and skin peeling (Nikolsky sign positive), usually following a prodrome of fever and irritability, not chronic diarrhea. * **D. Toxic epidermal necrolysis (TEN):** A severe drug reaction involving >30% body surface area skin detachment and mucosal involvement. It is an acute, life-threatening emergency, not a chronic condition associated with nutritional malabsorption. **High-Yield Pearls for NEET-PG:** * **Inheritance:** Autosomal Recessive (SLC39A4 mutation). * **Diagnosis:** Low serum zinc levels (though clinical response to zinc is definitive). * **Treatment:** Lifelong oral **Zinc supplementation** (elemental zinc 1-3 mg/kg/day). * **Acquired Form:** Can occur in patients on prolonged Total Parenteral Nutrition (TPN) without zinc supplementation or in severe malabsorption syndromes.

Q: What is the best treatment for a strawberry angioma?

Observation. **Explanation:** **Strawberry Angioma (Infantile Hemangioma)** is the most common benign vascular tumor of childhood. The correct management strategy is **Observation** because of the natural history of the lesion, which follows a predictable pattern of evolution: 1. **Proliferative Phase:** Rapid growth during the first 6–12 months. 2. **Involuting Phase:** Spontaneous regression begins (indicated by a color change from bright red to dull gray). 3. **Involuted Phase:** Complete resolution in 50% of children by age 5 and 90% by age 9 ("50% by 5, 90% by 9" rule). Since most lesions resolve spontaneously with excellent cosmetic outcomes, active intervention is usually unnecessary. **Analysis of Incorrect Options:** * **Sclerotherapy (A):** Generally reserved for venous malformations, not typically used for capillary hemangiomas due to the risk of tissue necrosis. * **Corticosteroids (B):** Previously the first-line medical treatment, but they have been replaced by **Propranolol** (oral beta-blockers) for complicated cases. * **Excision (D):** Surgical removal is avoided in the proliferative phase due to high vascularity and risk of scarring. It is only considered for residual fibrofatty tissue after involution is complete. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** If the lesion obstructs the airway, vision (amblyopia), or is ulcerated, the first-line treatment is **Oral Propranolol**. * **PHACE Syndrome:** Large facial hemangiomas may be associated with Posterior fossa malformations, Hemangiomas, Arterial anomalies, Cardiac defects, and Eye abnormalities. * **Kasabach-Merritt Syndrome:** This is **NOT** associated with strawberry angiomas; it occurs with Tufted Angiomas or Kaposiform Hemangioendotheliomas.

Q: Which of the following is NOT true regarding tuberous sclerosis?

Cafe au lait macules exclude the diagnosis. **Explanation:** **Tuberous Sclerosis Complex (TSC)** is a multi-system neurocutaneous syndrome. The correct answer is **C** because **Café au lait macules (CALMs)** do not exclude the diagnosis of Tuberous sclerosis. While CALMs are the hallmark of Neurofibromatosis Type 1 (NF1), they can occur in approximately 15–30% of patients with TSC. Their presence does not negate a TSC diagnosis if other major/minor criteria are met. **Analysis of other options:** * **Option A (Autosomal dominant/sporadic):** TSC is an autosomal dominant disorder involving mutations in *TSC1* (hamartin) or *TSC2* (tuberin). However, about 60–70% of cases arise from **spontaneous (sporadic) mutations**, making this statement true. * **Option B (Vogt triad):** The classic triad of **Epiloia** (Epi: Epilepsy, Loi: Low Intelligence, A: Adenoma sebaceum) is seen in about 30% of patients. * **Option C (Fibrous facial plaque):** Also known as a forehead plaque, this is a major clinical criterion for TSC. It is a connective tissue nevus that often appears earlier than facial angiofibromas. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign:** Ash-leaf spots (hypopigmented macules) – best seen under **Wood’s lamp**. * **Pathognomonic sign:** Shagreen patch (connective tissue nevus usually on the lumbosacral area). * **Facial Angiofibromas:** Historically called "Adenoma Sebaceum" (a misnomer as they are neither adnexal nor sebaceous). * **Koenen tumors:** Periungual fibromas appearing after puberty. * **Systemic findings:** Cardiac rhabdomyomas (often regress), Renal Angiomyolipomas (AML), and Cortical tubers (causing seizures).

Q: Sturge-Weber syndrome is associated with which of the following?

Hemangiosarcoma. **Explanation:** Sturge-Weber Syndrome (SWS), also known as encephalotrigeminal angiomatosis, is a neurocutaneous disorder characterized by vascular malformations. **Why Option A is the Correct Answer:** The hallmark cutaneous finding in Sturge-Weber syndrome is a **Port-wine stain (Nevus Flammeus)**. This is a congenital capillary malformation that typically presents as a unilateral, blanchable, maculopapular lesion. In SWS, it characteristically involves the skin supplied by the **trigeminal nerve**, most commonly the ophthalmic (V1) and maxillary (V2) distributions. It is associated with underlying leptomeningeal angiomas and glaucoma. *(Note: The prompt indicates Option D as correct; however, in medical literature and standard NEET-PG curriculum, Port-wine stain is the definitive association. Hemangiosarcoma is a malignant tumor not associated with SWS.)* **Analysis of Incorrect Options:** * **B. Cavernous hemangioma:** These are deep vascular malformations (now termed venous malformations) not typically associated with the classic triad of SWS. * **C. Lymphangioma:** These are malformations of the lymphatic system (e.g., cystic hygroma) and are unrelated to the capillary-venous pathology of SWS. * **D. Hemangiosarcoma:** This is a rare, highly malignant neoplasm of endothelial cells. It is not a feature of Sturge-Weber syndrome, which consists of benign vascular malformations. **NEET-PG High-Yield Pearls:** * **Classic Triad:** Port-wine stain (V1/V2 distribution), Leptomeningeal angiomatosis (leading to seizures/hemiparesis), and Glaucoma. * **Radiology:** "Tram-track" calcifications on CT/X-ray due to calcification of the underlying gyri. * **Genetics:** Caused by a somatic mutation in the **GNAQ gene**. * **Management:** Pulsed Dye Laser (PDL) is the gold standard for treating the Port-wine stain.

Q: Which of the following conditions is characterized by the finding shown below?

Sturge-Weber syndrome. ***Sturge-Weber syndrome*** - Characterized by a **port-wine stain (nevus flammeus)** typically in the **trigeminal nerve distribution** on the face, which is the pathognomonic dermatological finding. - Associated with **leptomeningeal angiomatosis**, **seizures**, and **glaucoma**, making the facial port-wine stain a key diagnostic marker. *Neurofibromatosis type 1* - Primary dermatological findings include **café-au-lait macules** (≥6 spots >5mm prepubertal, >15mm postpubertal) and **neurofibromas**. - Also presents with **axillary/inguinal freckling** and **Lisch nodules** in the iris, not port-wine stains. *Tuberous sclerosis* - Characterized by **ash-leaf spots** (hypopigmented macules), **shagreen patches**, and **facial angiofibromas** (adenoma sebaceum). - **Periungual fibromas** and **forehead plaques** are also typical, but port-wine stains are not associated with this condition. *Von Hippel-Lindau disease* - Primarily affects **internal organs** with **retinal angiomas**, **cerebellar hemangioblastomas**, and **renal cell carcinomas**. - Has **minimal cutaneous manifestations** and is not associated with facial port-wine stains or other distinctive skin findings.

Question 1

What are the common sites for a Mongolian spot?

Accepted Answer

Lumbo-sacral area

Answer

Face

Answer

Neck

Answer

Leg

Question 2

Koenen's periungual fibromas are seen in > 50% of cases with which condition?

Accepted Answer

Tuberous sclerosis

Answer

Sturge-Weber syndrome

Answer

Ataxia telangiectasia

Answer

Neurofibromatosis

Question 3

A patient presents with seizures, adenoma sebaceum, and mental retardation. What is the diagnosis?

Accepted Answer

Tuberous sclerosis

Answer

Sturge Weber syndrome

Answer

Neurofibromatosis

Answer

Neurocysticercosis

Question 4

What is the recommended treatment for a child presenting with an erythematous, non-blanching, bosselated lesion on the right side of the face?

Accepted Answer

Flash light pumped dye laser

Answer

Erbium laser

Answer

Nd-YAG laser

Answer

Q-switched ruby laser

Question 5

A 1 and 1/2 year old child with a history of chronic diarrhea presents with perioral and perineal rash. What is your diagnosis?

Accepted Answer

Acrodermatitis enteropathica

Answer

Epidermolysis bullosa

Answer

Staphylococcal scalded skin syndrome

Answer

Toxic epidermal necrolysis

Question 6

What is the best treatment for a strawberry angioma?

Accepted Answer

Observation

Answer

Sclerotherapy

Answer

Corticosteroids

Answer

Excision

Question 7

Which of the following is NOT true regarding tuberous sclerosis?

Accepted Answer

Cafe au lait macules exclude the diagnosis

Answer

Autosomal dominant sporadic transmission

Answer

Vogt triad of epiloia

Answer

Fibrous facial plaque

Question 8

Sturge-Weber syndrome is associated with which of the following?

Accepted Answer

Hemangiosarcoma

Answer

Port wine stain

Answer

Cavernous hemangioma

Answer

Lymphangioma

Question 9

Which of the following conditions is characterized by the finding shown below?

Accepted Answer

Sturge-Weber syndrome

Answer

Neurofibromatosis type 1

Answer

Tuberous sclerosis

Answer

Von Hippel-Lindau disease

Question 10

What is the most common clinical sign or symptom for the diagnosis of PHACE syndrome?

Accepted Answer

A 6-month-old child with blindness on the same side as a large facial lesion

Answer

An infant with infantile spasms, a hypsarrhythmic EEG pattern, and ash-leaf depigmentation on her back

Answer

An 18-year-old patient with a history of fractures and optic gliomas, who now has developed a malignant schwannoma

Answer

A 2-year-old child with multiple episodes of skin infection and failure to thrive

Pediatric Dermatology — MCQs

Pediatric Dermatology — MCQs

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