Pediatric Dermatology — MCQs

Pediatric Dermatology Indian Medical PG Practice Questions and MCQs

Question 41: Koenen's periungual fibromas are seen in > 50% of cases with which condition?

A. Tuberous sclerosis (Correct Answer)
B. Sturge-Weber syndrome
C. Ataxia telangiectasia
D. Neurofibromatosis

Explanation: **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).

Question 42: Stroke bite lesion is seen in which of the following conditions?

A. Sturge-Weber syndrome
B. Blue rubber bleb nevus syndrome
C. Macular staining of the infant (Correct Answer)
D. Craniofacial nevus

Explanation: **Explanation:** **Macular staining of the infant** (Option C) is the correct answer. This condition, also known as **Nevus Simplex**, is the most common vascular lesion in newborns. It results from persistent fetal dermal capillaries. These lesions are characteristically pink, flat, and blanchable. They are colloquially named based on their location: * **"Stork bite" (Unna’s nevus):** Located on the nape of the neck. * **"Angel’s kiss":** Located on the forehead, glabella, or eyelids. Unlike other vascular malformations, these are benign and usually fade spontaneously within the first year of life (except for those on the nape, which may persist). **Analysis of Incorrect Options:** * **Sturge-Weber Syndrome (A):** Associated with a **Port-wine stain** (Nevus Flammeus), which is a permanent capillary malformation typically following the distribution of the Trigeminal nerve (V1/V2). It does not regress and is associated with glaucoma and leptomeningeal angiomas. * **Blue Rubber Bleb Nevus Syndrome (B):** Characterized by multiple, soft, compressible blue venous malformations in the skin and gastrointestinal tract, often leading to GI bleeding and anemia. * **Craniofacial Nevus (D):** This is a broad term often used to describe Port-wine stains or other congenital nevi, but it is not the specific clinical term for the transient macular stains described as "stork bites." **High-Yield Clinical Pearls for NEET-PG:** * **Salmon Patch:** Another synonym for Macular stain/Nevus Simplex. * **Management:** Reassurance is key; no treatment is required as they are self-limiting. * **Differentiating Feature:** Unlike Port-wine stains, Stork bites are often **midline** and become more prominent during crying or temperature changes.

Question 43: Hutchinson's triad of congenital syphilis includes all of the following except?

A. Eighth nerve deafness
B. Interstitial keratitis
C. Hutchinson's teeth
D. Saddle nose (Correct Answer)

Explanation: **Explanation:** **Hutchinson’s Triad** is a classic clinical marker for **Late Congenital Syphilis** (presenting after 2 years of age). It consists of three specific findings: 1. **Interstitial Keratitis:** Inflammation of the corneal stroma, often leading to corneal scarring and blindness. 2. **Eighth Nerve Deafness:** Sensorineural hearing loss caused by labyrinthitis or auditory nerve involvement. 3. **Hutchinson’s Teeth:** Characteristic permanent upper central incisors that are peg-shaped, widely spaced, and notched. **Why "Saddle Nose" is the correct answer (the "Except"):** While **Saddle nose** (collapse of the nasal bridge due to destruction of the bony septum) is a classic feature of congenital syphilis, it is **not** part of the formal Hutchinson’s Triad. It is considered a separate skeletal stigma of the disease. **Analysis of Options:** * **Option A (Eighth nerve deafness):** Part of the triad; typically presents around puberty. * **Option B (Interstitial keratitis):** Part of the triad; the most common late manifestation. * **Option C (Hutchinson's teeth):** Part of the triad; affects permanent dentition, not deciduous teeth. **High-Yield Clinical Pearls for NEET-PG:** * **Mulberry Molars:** Another dental finding in late syphilis involving the first lower molars (multiple cusps). * **Clutton’s Joints:** Symmetrical, painless swelling of the knees (late syphilis). * **Early Congenital Syphilis (<2 years):** Look for **Snuffles** (syphilitic rhinitis), **Pemphigus syphiliticus** (bullous lesions on palms/soles), and **Condyloma lata**. * **Wimberger’s Sign:** Focal erosion of the medial proximal tibial metaphysis (pathognomonic on X-ray).

Question 44: What is the recommended treatment for a child presenting with an erythematous, non-blanching, bosselated lesion on the right side of the face?

A. Erbium laser
B. Nd-YAG laser
C. Flash light pumped dye laser (Correct Answer)
D. Q-switched ruby laser

Explanation: ### **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.

Question 45: What is the treatment of choice for Mongolian spots?

A. Laser therapy
B. Skin grafting
C. Steroids
D. None of the above (Correct Answer)

Explanation: **Explanation:** **Mongolian spots** (Congenital Dermal Melanocytosis) are the most common birthmarks in neonates, particularly in those of Asian and African descent. The correct answer is **None of the above** because these lesions are entirely **benign and typically self-limiting**. 1. **Why "None of the above" is correct:** Mongolian spots occur due to the failure of melanocytes to migrate from the neural crest to the epidermis, leaving them trapped in the deeper dermis. Since the majority of these spots **spontaneously regress** by early childhood (usually by age 2–6 years) and carry zero risk of malignancy, no medical or surgical intervention is required. Reassurance of the parents is the primary management. 2. **Why other options are incorrect:** * **Laser therapy:** While Q-switched lasers can be used for persistent dermal melanocytosis (like Nevus of Ota), they are unnecessary for Mongolian spots due to their natural resolution. * **Skin grafting:** This is an invasive surgical procedure reserved for skin loss or malignancies; it is contraindicated for a benign, resolving pigmentary condition. * **Steroids:** These have no role in treating melanocytic lesions and are used for inflammatory or vascular conditions (like infantile hemangiomas). **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most commonly found in the **lumbosacral region**. * **Appearance:** Blue-grey, slate-colored, non-blanching macules with indefinite borders. * **Histology:** Shows spindle-shaped melanocytes scattered between collagen bundles in the lower two-thirds of the dermis (**Tyndall effect** causes the blue color). * **Differential Diagnosis:** Must be distinguished from physical child abuse (bruises); however, Mongolian spots do not change color over days or show tenderness.

Question 46: What is the best treatment for a strawberry angioma?

A. Sclerotherapy
B. Corticosteroids
C. Observation (Correct Answer)
D. Excision

Explanation: **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.

Question 47: Acrodermatitis enteropathica occurs due to which deficiency?

A. Copper deficiency
B. Zinc deficiency (Correct Answer)
C. Iron deficiency
D. Folic acid deficiency

Explanation: **Explanation:** **Acrodermatitis Enteropathica (AE)** is a rare genetic or acquired disorder caused by **Zinc deficiency**. The classic hereditary form is an autosomal recessive condition involving a mutation in the **SLC39A4 gene**, which encodes the ZIP4 transporter responsible for zinc absorption in the duodenum and jejunum. **Why Zinc is the Correct Answer:** Zinc is a vital cofactor for over 300 enzymes involved in DNA synthesis and cell division. Its deficiency leads to the hallmark triad of AE: **Periorificial and acral dermatitis** (vesiculobullous, eczematous, or psoriasiform lesions), **Alopecia**, and **Diarrhea**. Symptoms typically manifest in infants shortly after weaning from breast milk, as breast milk contains a zinc-binding ligand that facilitates absorption, which is absent in cow's milk. **Why Other Options are Incorrect:** * **Copper Deficiency:** Typically presents with hematological abnormalities (anemia, neutropenia) and neurological symptoms (myelopathy), but not the specific periorificial rash of AE. * **Iron Deficiency:** Primarily manifests as microcytic hypochromic anemia, koilonychia (spoon-shaped nails), and glossitis. * **Folic Acid Deficiency:** Leads to megaloblastic anemia and neural tube defects; skin changes are rare and usually limited to hyperpigmentation. **NEET-PG High-Yield Pearls:** * **The Triad:** Dermatitis (acral/periorificial) + Alopecia + Diarrhea. * **Inheritance:** Autosomal Recessive (SLC39A4 gene). * **Clinical Clue:** Lesions are often secondarily infected with *Candida albicans*. * **Diagnosis:** Low serum zinc levels (standard) and low serum alkaline phosphatase (since it is a zinc-dependent enzyme). * **Treatment:** Lifelong oral zinc supplementation (elemental zinc 1–3 mg/kg/day).

Question 48: What is the most common early finding in Tuberous Sclerosis Complex?

A. Shagreen's patch
B. Axillary freckling
C. Adenoma sebaceum
D. Ash leaf spot (Correct Answer)

Explanation: **Explanation:** **Tuberous Sclerosis Complex (TSC)**, also known as Bourneville’s disease, is an autosomal dominant neurocutaneous syndrome characterized by hamartomas in multiple organs. **Why Ash Leaf Spot is the correct answer:** **Ash leaf spots (Hypomelanotic macules)** are the **earliest** cutaneous sign of TSC, often present at birth or appearing in early infancy. They are typically lanceolate (leaf-shaped) and are best visualized using a **Wood’s lamp**, which accentuates the contrast between the hypopigmented area and normal skin. Having three or more such macules is a major diagnostic criterion. **Analysis of Incorrect Options:** * **Shagreen’s patch:** This is a connective tissue nevus (leathery, orange-peel texture) usually found on the lumbosacral area. It typically appears later in childhood (usually after age 5). * **Axillary freckling (Crowe’s sign):** This is a characteristic feature of **Neurofibromatosis Type 1 (NF-1)**, not Tuberous Sclerosis. * **Adenoma sebaceum:** These are actually **facial angiofibromas**. While they are the most characteristic finding of TSC, they usually appear between ages 2 and 5 and are rarely present at birth. **High-Yield Clinical Pearls for NEET-PG:** * **Vogt’s Triad:** Epilepsy, Mental retardation, and Adenoma sebaceum (seen in only 30% of cases). * **Koenen’s tumor:** Periungual angiofibromas that appear during puberty. * **Confetti lesions:** Multiple small, 1-2 mm hypopigmented macules; highly specific for TSC. * **Genetics:** Mutations in **TSC1 (Hamartin)** on chromosome 9 or **TSC2 (Tuberin)** on chromosome 16. * **Systemic findings:** Cardiac rhabdomyomas (often regress), Renal Angiomyolipomas (AML), and Subependymal Giant Cell Astrocytomas (SEGA).

Question 49: A 3-year-old child presents with eczematous dermatitis on extensor surfaces. His mother reports a history of bronchial asthma. What is the most likely diagnosis?

A. Atopic dermatitis (Correct Answer)
B. Contact dermatitis
C. Seborrheic dermatitis
D. Infantile eczematous dermatitis

Explanation: ### Explanation **Correct Answer: A. Atopic Dermatitis** The diagnosis is based on the **Atopic Triad** (asthma, allergic rhinitis, and atopic dermatitis) and the age-specific distribution of lesions. Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease characterized by pruritus and defective skin barrier function (often due to **Filaggrin** mutations). In children aged 2–12 years (Childhood phase), the distribution typically shifts from the face to the **extensor surfaces** and flexures (wrists, ankles). The presence of bronchial asthma in this child strongly supports an "atopic diathesis," making AD the most likely diagnosis. **Analysis of Incorrect Options:** * **B. Contact Dermatitis:** This is an exogenous reaction to an allergen or irritant. It presents with localized lesions at the site of contact (e.g., nickel, detergents) and is not typically associated with a systemic history of asthma. * **C. Seborrheic Dermatitis:** Usually presents in infants (Cradle cap) or adults. It involves "greasy" yellowish scales in sebum-rich areas (scalp, nasolabial folds, axilla) and is generally non-pruritic, unlike AD. * **D. Infantile Eczematous Dermatitis:** This term usually refers to the infantile phase of AD (birth to 2 years), which characteristically involves the **face (cheeks)** and scalp, rather than the extensors in a 3-year-old. **High-Yield Clinical Pearls for NEET-PG:** * **Hanifin and Rajka Criteria:** The gold standard for diagnosing AD. * **Age-wise Distribution:** * *Infants:* Face, scalp, and extensors. * *Children:* Flexures (antecubital/popliteal fossae) and extensors. * *Adults:* Flexural folds, hands, and eyelids. * **Dennie-Morgan Fold:** An extra fold of skin under the lower eyelid, a classic sign of AD. * **Management:** First-line treatment involves emollients and topical corticosteroids or calcineurin inhibitors (Tacrolimus).

Question 50: All of the following statements regarding Sturge Weber syndrome are true, EXCEPT:

A. Characterized by nevus flammeus
B. Diffuse choroidal hemangioma may be seen in up to 40% of the cases
C. Up to 85% of individuals may suffer from seizure disorder
D. Mental retardation is seen in only less than 15% of individuals (Correct Answer)

Explanation: **Explanation:** Sturge-Weber Syndrome (SWS), or encephalotrigeminal angiomatosis, is a sporadic neurocutaneous disorder characterized by the triad of a facial port-wine stain, leptomeningeal angiomas, and ocular involvement. **Why Option D is the Correct Answer (The False Statement):** Mental retardation (intellectual disability) is a common manifestation of SWS, occurring in approximately **50% to 60%** of affected individuals. The cognitive impairment is often progressive and correlates with the severity of seizures and the extent of leptomeningeal involvement. Therefore, stating it occurs in less than 15% is clinically inaccurate. **Analysis of Other Options:** * **Option A:** **Nevus flammeus (Port-wine stain)** is the hallmark cutaneous finding. It is usually unilateral and follows the distribution of the trigeminal nerve (most commonly the V1 and V2 branches). * **Option B:** **Diffuse choroidal hemangioma** is a classic ocular finding seen in about 40% of patients, often described as a "tomato-catsup" fundus. Glaucoma is another critical ocular complication (seen in ~30-70%). * **Option C:** **Seizures** are the most common neurological complication, affecting **75% to 90%** of patients. They typically onset within the first year of life and are often focal and contralateral to the skin lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** Caused by a somatic mutation in the **GNAQ gene**. * **Radiology:** Skull X-ray or CT shows **"Tram-track" calcifications** (gyriform cortical calcifications). * **Treatment:** Port-wine stains are treated with **Pulsed Dye Laser (PDL)**; seizures require aggressive medical or surgical management to prevent cognitive decline. * **Mnemonic:** SWS — **S**eizures, **W**ine stain, **S**tram-track calcifications.

Practice by Chapter

Neonatal Dermatology

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Infantile Hemangiomas and Vascular Malformations

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Atopic Dermatitis in Children

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Acne in Childhood and Adolescence

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Childhood Exanthems

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Genetic Skin Disorders in Children

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Genodermatoses

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Nutritional Dermatoses in Children

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Pigmentary Disorders in Children

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Hair Disorders in Children

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Child Abuse: Cutaneous Manifestations

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Therapeutic Considerations in Pediatric Dermatology

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