Basic Dermatology Practice Questions

Q: Which skin condition is associated with the hepatitis C virus?

Lichen planus. **Explanation:** **Lichen Planus (LP)** is the correct answer. There is a well-established epidemiological association between Hepatitis C Virus (HCV) infection and Lichen Planus. While the exact pathogenesis is debated, it is believed that HCV-specific T-cells may cross-react with antigens in the basal layer of the keratinocytes, or the virus may replicate within the skin and oral mucosa, triggering a cell-mediated immune response. This association is strongest with the **erosive oral** variant of Lichen Planus. **Analysis of Incorrect Options:** * **A. Leprosy:** Caused by *Mycobacterium leprae*. It is a chronic granulomatous bacterial infection, not associated with viral hepatitis. * **C. Psoriasis:** An immune-mediated inflammatory disease primarily driven by the IL-23/IL-17 axis. While it can coexist with various systemic conditions, it has no specific causal or strong epidemiological link to HCV. * **D. Vitiligo:** An autoimmune destruction of melanocytes. It is frequently associated with other autoimmune disorders (like Hashimoto’s thyroiditis or Type 1 Diabetes) but not specifically with Hepatitis C. **Clinical Pearls for NEET-PG:** * **The "6 Ps" of Lichen Planus:** Planar (flat-topped), Purple, Polygonal, Pruritic, Papules, and Plaques. * **Wickham Striae:** Fine white reticular patterns seen on the surface of the lesions. * **Koebner Phenomenon:** Development of lesions at sites of trauma (also seen in Psoriasis and Vitiligo). * **Other HCV-associated skin conditions:** Porphyria Cutanea Tarda (PCT), Cryoglobulinemic vasculitis, and Necrolytic Acral Erythema (highly specific for HCV).

Q: Target lesions are characteristic of which of the following conditions?

Erythema multiforme. **Explanation:** **Erythema Multiforme (EM)** is a hypersensitivity reaction most commonly triggered by infections, particularly **Herpes Simplex Virus (HSV)**. The hallmark clinical feature is the **Target (Iris) Lesion**. A classic target lesion consists of three concentric zones: 1. A dusky, central disk (sometimes with a vesicle or bulla). 2. A pale, edematous intermediate ring. 3. An erythematous outer halo. These lesions are typically distributed symmetrically on the acral extremities (palms and soles). **Analysis of Incorrect Options:** * **Erythema Marginatum:** Seen in Acute Rheumatic Fever. It presents as evanescent, pink, ring-like (annular) patches with elevated borders and central clearing, primarily on the trunk. * **Lichen Planus:** Characterized by the "6 Ps" (Planar, Purple, Polygonal, Pruritic, Papules, and Plaques). It features **Wickham striae** (white lacy patterns) rather than target lesions. * **Psoriasis:** Presents as well-demarcated erythematous plaques with silvery-white scales. Key signs include the **Auspitz sign** and **Koebner phenomenon**. **High-Yield Clinical Pearls for NEET-PG:** * **Most common trigger for EM Minor:** Herpes Simplex Virus (HSV-1 and HSV-2). * **Most common trigger for EM Major:** *Mycoplasma pneumoniae*. * **EM vs. SJS/TEN:** EM is now considered a distinct condition from Stevens-Johnson Syndrome (SJS). SJS/TEN are primarily drug-induced and involve significant mucosal sloughing, whereas EM is usually post-infectious. * **Atypical Target Lesions:** These have only two zones and are more characteristic of SJS.

Q: An 18-year-old female presents with itchy erythema and swelling of the toes every winter season. What is the most likely diagnosis?

Chilblains. **Explanation:** The correct diagnosis is **Chilblains (Pernio)**. This is an inflammatory condition caused by an abnormal vascular response to **non-freezing cold and damp weather**. **Why Chilblains is correct:** Chilblains typically affects young females and presents as itchy (pruritic), painful, erythematous, or cyanotic swellings on the distal extremities (toes and fingers). The pathophysiology involves cold-induced vasoconstriction followed by rapid rewarming, which causes localized inflammation and edema. The seasonal recurrence (every winter) is a classic hallmark of this condition. **Why other options are incorrect:** * **Raynaud’s Disease/Phenomenon:** These present with a classic **triphasic color change** (White/Pallor → Blue/Cyanosis → Red/Rubor) triggered by cold. While it affects the extremities, it is characterized by vasospasm rather than the persistent itchy, inflammatory swelling seen in Chilblains. * **Frostbite:** This involves actual **freezing of tissues** (ice crystal formation) due to exposure to temperatures below freezing point ($<0^\circ C$). It results in tissue necrosis and is an acute injury rather than a seasonal, recurring itchy erythema. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** Keep the area warm and dry. **Nifedipine** (a Calcium Channel Blocker) is the drug of choice for chronic or severe cases as it promotes vasodilation. * **Differential:** Unlike Frostbite (freezing injury) or Trench Foot (prolonged immersion in cold water), Chilblains is a localized inflammatory response. * **Secondary Pernio:** If it occurs in older patients, consider screening for systemic lupus erythematosus (SLE).

Q: Which of the following statements about Langerhans cells is true?

They play an immunological role in the skin.. ### Explanation **Correct Answer: D. They play an immunological role in the skin.** Langerhans cells (LCs) are specialized **dendritic cells** derived from the bone marrow. They are the primary **antigen-presenting cells (APCs)** of the skin. Their main function is to capture antigens entering the epidermis, process them, and migrate to regional lymph nodes to present them to T-lymphocytes, thereby initiating a cutaneous immune response (Type IV hypersensitivity). **Why the other options are incorrect:** * **Option A:** Langerhans cells are primarily located in the **stratum spinosum** of the **epidermis**, not the dermis. While they can migrate through the dermis to reach lymphatics, their resident home is the epidermis. * **Option B:** **Merkel cells** function as sensory mechanoreceptors (light touch). * **Option C:** **Krause end bulbs** are the specialized nerve endings traditionally associated with cold thermoreception. **High-Yield Clinical Pearls for NEET-PG:** * **Origin:** Bone marrow (Mesodermal). * **Microscopy:** On Electron Microscopy, they show characteristic rod or tennis-racket shaped granules called **Birbeck Granules**. * **Markers:** They are positive for **S-100**, **CD1a**, and **Langerin (CD207)**. Langerin is the most specific marker and is involved in the formation of Birbeck granules. * **Clinical Correlation:** **Langerhans Cell Histiocytosis (LCH)** is a proliferative disorder of these cells, often presenting with seborrheic dermatitis-like rashes in infants and "punched-out" bone lesions.

Q: A 60-year-old man presents to his physician after a routine screening test indicates hyperlipidemia. Physical examination reveals raised, irregular, yellow papules in the skin of the soft tissues below the eyes. Biopsy of these lesions would most likely show which of the following?

Multinucleated giant cells. **Explanation:** The clinical presentation of a 60-year-old man with hyperlipidemia and yellow papules on the soft tissues below the eyes (periorbital region) is classic for **Xanthelasma palpebrarum**. Xanthelasma is a type of xanthoma characterized by the accumulation of lipids within dermal macrophages. On histopathology, these lipid-laden macrophages are known as **foam cells** (or xanthoma cells). In many xanthomatous lesions, these macrophages fuse to form **Touton multinucleated giant cells**, which feature a ring of nuclei surrounding a central non-foamy cytoplasm, with peripheral foamy cytoplasm. Therefore, **Option D** is the correct histopathological finding. **Analysis of Incorrect Options:** * **Options A & B:** Nevus cells (benign or malignant) are characteristic of melanocytic nevi or melanoma. While these can present as papules, they are typically pigmented (brown/black) rather than yellow and are not associated with hyperlipidemia. * **Option C:** Microscopic blisters (vesicles/bullae) are seen in immunobullous disorders (e.g., Pemphigus, Bullous Pemphigoid) or infections (e.g., Herpes). They do not present as solid yellow papules. **NEET-PG High-Yield Pearls:** * **Xanthelasma palpebrarum** is the most common type of xanthoma. * While often associated with **Type II and Type IV hyperlipoproteinemia**, 50% of patients with xanthelasma are normolipemic. * **Touton Giant Cells** are a hallmark of xanthomatous inflammation and are also seen in Juvenile Xanthogranuloma. * **Eruptive Xanthomas** (small yellow papules on extensors) are specifically associated with high **triglycerides**.

Q: A 50-year-old male patient presented with characteristic skin lesions on the right shin. The skin lesion is a single indurated yellowish-brown plaque with an atrophic centre. Ectatic blood vessels are visible through the thinned skin. A biopsy was taken and histopathology examination was performed. Which of the following is the next best investigation to be done in this patient?

Blood sugar levels. ### Explanation The clinical presentation described—a single indurated, yellowish-brown plaque with an atrophic center and prominent telangiectasia (ectatic blood vessels) on the pretibial area (shin)—is the classic description of **Necrobiosis Lipoidica (NL)**. **1. Why Blood Sugar Levels is the Correct Answer:** Necrobiosis Lipoidica is a chronic granulomatous dermatitis strongly associated with **Diabetes Mellitus**. While only about 0.3% of diabetic patients develop NL, approximately **60–75% of patients with NL have or will develop diabetes**. Therefore, the immediate next step in management is to screen for underlying glucose intolerance or undiagnosed diabetes using blood sugar levels (Fasting/PP) or HbA1c. **2. Why Other Options are Incorrect:** * **Thyroid Function Tests:** These are used to investigate conditions like *Pretibial Myxedema* (Grave’s disease), which presents as waxy, "orange-peel" (peau d'orange) indurated nodules, not atrophic yellowish plaques. * **Serum Cortisol Levels:** Used to diagnose Cushing’s syndrome or Addison’s disease. While Cushing’s can cause skin thinning and striae, it does not present with localized necrobiotic plaques. * **Serum Growth Hormone:** Used for Acromegaly, which presents with skin thickening (pachydermia) and cutis verticis gyrata, rather than atrophy and telangiectasia. **3. NEET-PG High-Yield Pearls:** * **Histopathology of NL:** Shows "tiered" or "layer-cake" granulomas involving the full thickness of the dermis, consisting of necrobiotic collagen alternating with inflammatory cells. * **Key Differentiator:** Unlike Granuloma Annulare (which also shows necrobiosis), NL typically shows **plasma cells** and lacks prominent mucin. * **Clinical Fact:** The severity of NL does **not** correlate with glycemic control; however, screening is mandatory due to the high association. * **Common Site:** The pretibial area (shins) is the most common site (85% of cases).

Q: Tylosis is associated with which of the following conditions?

Oesophageal Carcinoma. **Explanation:** **Tylosis** (also known as *Howel-Evans syndrome*) is a rare autosomal dominant genetic disorder characterized by focal hyperkeratosis of the palms and soles (palmoplantar keratoderma). **Why Oesophageal Carcinoma is Correct:** The association between Tylosis and **Squamous Cell Carcinoma (SCC) of the oesophagus** is one of the strongest genetic predispositions in gastrointestinal pathology. It is caused by a mutation in the **RHBDF2 gene** on chromosome 17q25. Individuals with this syndrome have a lifetime risk of developing oesophageal cancer approaching **90%** by age 70. This makes regular endoscopic surveillance mandatory for these patients. **Why Other Options are Incorrect:** * **B, C, and D:** While Uterine, Gastric, and Prostatic carcinomas have various genetic and environmental risk factors (e.g., *BRCA* mutations for prostate/uterine, *H. pylori* or *CDH1* for gastric), they have no established clinical or genetic link with palmoplantar keratoderma or the RHBDF2 mutation. **High-Yield Clinical Pearls for NEET-PG:** * **Type of Cancer:** Tylosis is specifically associated with **Squamous Cell Carcinoma**, not Adenocarcinoma. * **Triad:** Look for the triad of palmoplantar hyperkeratosis, oral leukoplakia, and oesophageal SCC in clinical vignettes. * **Other Oesophageal SCC Risk Factors:** Plummer-Vinson Syndrome (Iron deficiency anemia + glossitis + esophageal webs), Achalasia cardia, and corrosive injury (strictures). * **Genetic Locus:** Chromosome **17q25** (Tylosis Oesophageal Cancer locus).

Q: Which of the following statements is not true regarding keloids?

They typically involve flexor surfaces of the limbs.. **Explanation:** Keloids are benign fibroproliferative growths resulting from an exaggerated healing response to skin injury. The correct answer is **D** because keloids characteristically involve **extensor surfaces** and areas of high skin tension, rather than flexor surfaces. **Why Option D is incorrect (The Correct Choice):** Keloids have a predilection for specific anatomical sites known as "keloid-prone areas." These include the **presternal area (most common)**, deltoid region, upper back, and earlobes. They typically avoid the face (except the jawline) and flexor creases. **Analysis of other options:** * **Option A:** Keloids most frequently affect individuals between **10 and 30 years** of age. They are rare in the very young or the elderly, likely due to the higher rate of collagen synthesis and skin tension in young adults. * **Option B:** This is the defining clinical feature of a keloid. Unlike hypertrophic scars (which stay within the wound boundary), keloids **extend beyond the margins** of the original injury and rarely regress spontaneously. * **Option C:** Epidemiological studies suggest a slightly **higher incidence in females**, often attributed to a higher frequency of ear piercing and cosmetic procedures. **NEET-PG High-Yield Pearls:** * **Histology:** Characterized by thick, eosinophilic, "glassy" **hyaline collagen bundles** (collagen type I and III). * **Genetics:** More common in darker skin types (Fitzpatrick IV-VI); associated with HLA-B14 and HLA-B21. * **Treatment:** Intralesional **Triamcinolone acetonide** (10–40 mg/mL) is the first-line therapy. Other options include cryotherapy, silicone gel sheeting, and pressure therapy. * **Key Distinction:** Hypertrophic scars appear early (4–6 weeks), stay within boundaries, and may regress; Keloids appear late (months to years), invade normal tissue, and do not regress.

Q: Lesions of pityriasis rosea are distributed mostly on which part of the body?

Trunk. ### Explanation **Pityriasis Rosea (PR)** is a common, self-limiting inflammatory skin disorder characterized by a specific clinical progression and distribution. **Why the Trunk is Correct:** The hallmark of Pityriasis Rosea is its distribution in the **"Christmas Tree" (or fir tree) pattern**. The lesions are primarily located on the **trunk** and proximal limbs. They follow the lines of cleavage (Langer’s lines), creating a symmetrical, V-shaped distribution on the upper back and a horizontal distribution on the lower back. The eruption typically begins with a single, large **"Herald Patch"** (usually on the trunk), followed days later by smaller, oval, erythematous scaly plaques with a characteristic **collarette of scale**. **Analysis of Incorrect Options:** * **A. Face:** PR is known for "sparing" the face in its classic form. Involvement of the face is rare and usually only seen in the "inverse" variant or in pediatric cases. * **C. Scalp:** Similar to the face, the scalp is typically spared. Scalp involvement is more characteristic of Psoriasis or Seborrheic Dermatitis. * **D. Palms and Soles:** These areas are characteristically spared in PR. This is a crucial diagnostic differentiator from **Secondary Syphilis**, which presents with similar scaly lesions but *includes* the palms and soles. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Associated with **HHV-6 and HHV-7** reactivation. * **Herald Patch:** The initial lesion; larger (2–6 cm), salmon-colored, and heralds the generalized eruption. * **Collarette Scale:** The scale is attached at the periphery and free toward the center. * **Hanging Curtain Sign:** When the skin is stretched across the long axis of the lesion, the scales fold like a curtain. * **Differential Diagnosis:** Always rule out Secondary Syphilis (perform VDRL/RPR if palms/soles are involved).

Question 1

Which skin condition is associated with the hepatitis C virus?

Accepted Answer

Lichen planus

Answer

Leprosy

Answer

Psoriasis

Answer

Vitiligo

Question 2

Target lesions are characteristic of which of the following conditions?

Accepted Answer

Erythema multiforme

Answer

Erythema marginatum

Answer

Lichen planus

Answer

Psoriasis

Question 3

An 18-year-old female presents with itchy erythema and swelling of the toes every winter season. What is the most likely diagnosis?

Accepted Answer

Chilblains

Answer

Raynaud's disease

Answer

Raynaud's phenomenon

Answer

Frostbite

Question 4

Which of the following statements about Langerhans cells is true?

Accepted Answer

They play an immunological role in the skin.

Answer

They are commonly found in the dermis.

Answer

They function as sensory mechanoreceptors.

Answer

They function as receptors for cold.

Question 5

A pinkish-red fluorescence of urine when examined with a Wood's lamp is seen in which condition?

Accepted Answer

Porphyria cutanea tarda

Answer

Lead poisoning

Answer

Erythromelalgia

Answer

Acrocyanosis

Question 6

A 60-year-old man presents to his physician after a routine screening test indicates hyperlipidemia. Physical examination reveals raised, irregular, yellow papules in the skin of the soft tissues below the eyes. Biopsy of these lesions would most likely show which of the following?

Accepted Answer

Multinucleated giant cells

Answer

Benign nevus cells

Answer

Malignant nevus cells

Answer

Microscopic blisters

Question 7

A 50-year-old male patient presented with characteristic skin lesions on the right shin. The skin lesion is a single indurated yellowish-brown plaque with an atrophic centre. Ectatic blood vessels are visible through the thinned skin. A biopsy was taken and histopathology examination was performed. Which of the following is the next best investigation to be done in this patient?

Accepted Answer

Blood sugar levels

Answer

Thyroid function tests

Answer

Serum cortisol levels

Answer

Serum growth hormone levels

Question 8

Tylosis is associated with which of the following conditions?

Accepted Answer

Oesophageal Carcinoma

Answer

Uterine Carcinoma

Answer

Gastric Carcinoma

Answer

Prostatic Carcinoma

Question 9

Which of the following statements is not true regarding keloids?

Accepted Answer

They typically involve flexor surfaces of the limbs.

Answer

The 10-30 year age group is more commonly involved.

Answer

The scar tissue outgrows the original wound area.

Answer

Females are more commonly affected than males.

Question 10

Lesions of pityriasis rosea are distributed mostly on which part of the body?

Accepted Answer

Trunk

Answer

Face

Answer

Scalp

Answer

Palms and soles

Basic Dermatology — MCQs

Basic Dermatology — MCQs

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