Basic Dermatology Practice Questions

Q: These lesions are seen in which of the following?

Erythema nodosum. ***Erythema nodosum*** - The image displays typical **erythematous, tender nodules**, consistent with **erythema nodosum**. - These lesions usually appear on the **shins** but can be found elsewhere, representing a form of **panniculitis**. *Erythema infectiosum* - Characterized by a distinctive **"slapped cheek" rash** on the face and a lacy, reticular rash on the body, which is not seen here. - It is caused by **parvovirus B19** and primarily affects children. *Erythema induratum* - Presents as chronic, recurring **tender nodules and plaques**, typically on the **calves**, often associated with tuberculosis. - While it is a form of panniculitis, its specific morphology and association with TB differ from the common presentation of erythema nodosum. *Erythema multiforme* - Known for its characteristic **target lesions** with multiple rings and a central blister or crust, often symmetrically distributed. - It is commonly triggered by infections (e.g., herpes simplex virus) or drugs, presenting with a different morphology from the image.

Q: A 65-year-old patient presents with development of multiple papules and nodules around the right knee for last one year. Which of the following hyper-lipoproteinemia is associated with this condition?

Type III Hyper-lipoproteinemia. ***Type III Hyperlipoproteinemia*** - The clinical presentation shows **tuberous or tuberoeruptive xanthomas**, which are firm papules and nodules developing slowly over months on extensor surfaces like knees and elbows - These are highly characteristic of **Type III hyperlipoproteinemia (familial dysbetalipoproteinemia)**, caused by accumulation of **chylomicron and VLDL remnants** - Type III involves a defect in **apolipoprotein E (apoE)**, leading to impaired clearance of remnant lipoproteins - **Pathognomonic feature**: Xanthoma striatum palmare (yellow-orange palmar creases) *Type I Hyperlipoproteinemia* - Characterized by severe elevation of **chylomicrons** and triglycerides due to **lipoprotein lipase deficiency** or apoC-II deficiency - Presents with **eruptive xanthomas** (small, sudden-onset yellow papules with red base) and **lipemia retinalis** - Eruptive xanthomas appear rapidly (days-weeks), unlike the slow development described in this case - Major complication: Recurrent acute pancreatitis *Type II Hyperlipoproteinemia* - Familial hypercholesterolemia with elevated **LDL cholesterol** - Manifests as **tendon xanthomas** (Achilles tendon, extensor tendons of hands), **xanthelasmas**, and corneal arcus - Does not typically cause nodular lesions around the knees *Type IV Hyperlipoproteinemia* - Characterized by elevated **VLDL** and triglycerides, often associated with metabolic syndrome - Rarely presents with xanthomas; when present, they are eruptive rather than tuberous - Main clinical concerns are cardiovascular disease and pancreatitis risk

Q: A 55-year-old patient presented with following lesions on his buttock. He consulted a general physician who diagnosed it as an allergy, but lesions are persisting. His blood sample was drawn and shows a creamy top layer. What is the diagnosis?

Eruptive xanthoma. ***Eruptive xanthoma*** - The image shows numerous 2-4 mm, yellowish-orange papules on the buttocks, characteristic of **eruptive xanthomas**, which are often found on extensor surfaces and buttocks. - The **creamy top layer** in the blood sample indicates severe **hypertriglyceridemia**, the underlying metabolic cause of eruptive xanthomas. *Tuberous xanthoma* - These are typically larger, painless, firm nodules found over extensor surfaces like elbows and knees, not small papules particularly on the buttocks. - While also associated with hyperlipidemia, they are usually seen with **elevated LDL cholesterol** rather than severe hypertriglyceridemia leading to a creamy serum layer. *Tendinous xanthoma* - These present as subcutaneous nodules that develop in tendons, most commonly the Achilles tendon and extensor tendons of the hands and feet. - They are primarily linked to **familial hypercholesterolemia** (elevated LDL) and would not manifest as small papules on the buttocks. *Xanthelasma palpebrarum* - These are soft, yellowish plaques that appear on or around the eyelids, and are distinct from the widespread papular lesions seen on the buttocks. - While sometimes associated with hyperlipidemia, they are confined to the periorbital area and do not present as generalized eruptive lesions.

Q: The following skin lesion can be seen in all except:

Normolipidemia. ***Normolipidemia*** - The image displays **xanthelasma**, which are soft, yellowish patches of cholesterol deposits, typically found on or around the eyelids. - While xanthelasma are strongly associated with **dyslipidemia**, they can occasionally occur in individuals with otherwise normal lipid levels, but normolipidemia itself does not cause them. - This is the correct answer as xanthelasma is **not typically seen** in normolipidemia. *Type III hyperlipidemia* - **Type III hyperlipidemia**, also known as familial dysbetalipoproteinemia, is characterized by elevated **chylomicron remnants** and **IDL**. - This condition is strongly associated with **xanthelasma** and other cutaneous xanthomas due to accumulation of cholesterol-rich lipoproteins. - Patients typically present with palmar xanthomas and tuberoeruptive xanthomas in addition to xanthelasma. *Diabetes mellitus* - **Diabetes mellitus** can lead to secondary dyslipidemia, increasing the risk of xanthelasma and other cutaneous manifestations of lipid deposition. - Poorly controlled diabetes is associated with elevated **triglycerides** and **VLDL**. - The metabolic dysfunction promotes cholesterol accumulation in tissues including the eyelid skin. *Secondary biliary cirrhosis* - **Secondary biliary cirrhosis** can cause significant **hypercholesterolemia** due to impaired bile acid excretion. - The accumulation of cholesterol can manifest as xanthelasma or other forms of **xanthomas**. - Cholestatic liver disease is a well-recognized cause of secondary hyperlipidemia and xanthelasma formation.

Q: A 26-year-old male presents with greasy papules on face and chest that feel like sandpaper. Palms and soles have minute pits. Skin biopsy was performed. What is the diagnosis?

Darier's disease. ***Darier's disease*** - The presentation of **greasy papules** on the face and chest resembling "sandpaper," along with **minute pits on palms and soles**, is classic for Darier's disease. - Histologically, Darier's disease is characterized by **dyskeratosis** (premature keratinization of individual keratinocytes) and **acantholysis** (loss of cohesion between keratinocytes), which would be seen on a skin biopsy. *Hailey-Hailey disease* - This condition typically presents with **flaccid vesicles and bullae** in intertriginous areas (e.g., axillae, groin) that rupture to form erosions. - Histology shows **acantholysis** (loss of cell adhesion) creating a "dilapidated brick wall" appearance, but without the prominent dyskeratosis seen in Darier's. *Epidermolysis bullosa* - This is a group of genetic disorders characterized by **extreme skin fragility** and the formation of **blisters** (bullae) in response to minimal trauma. - The clinical presentation with greasy papules and pits is not consistent with the primary blistering nature of epidermolysis bullosa. *Incontinentia pigmenti* - This X-linked dominant disorder primarily affects females and presents with **skin lesions in distinct stages** (vesicular, verrucous, hyperpigmented, atrophic) following Blaschko's lines. - It does not typically involve greasy papules or palmoplantar pitting in the manner described.

Q: This is the clinical presentation of a 5-year-old boy with lesions worsening in cold weather. His mother says these lesions developed after 1 year of age. His sister has same lesions which developed after 2 years of age. All are true about the condition except:

Steroid sulfatase defect. ***Steroid sulfatase defect*** - A **steroid sulfatase defect** is characteristic of **X-linked ichthyosis**, NOT the condition described here. - This case represents **ichthyosis vulgaris** based on: onset after 1 year of age, autosomal dominant inheritance (affects both siblings), worsening in cold weather, and flexural sparing. - X-linked ichthyosis typically presents at birth or within the first few months, has X-linked inheritance (predominantly males), lacks flexural sparing, and may have associated corneal opacities and cryptorchidism. - **This is the EXCEPTION** - steroid sulfatase defect is NOT true for this condition. *Flexural sparing* - **TRUE statement** - Flexural areas (axillae, antecubital and popliteal fossae, groin) tend to be spared in **ichthyosis vulgaris**. - This is a key distinguishing feature that differentiates ichthyosis vulgaris from X-linked ichthyosis (which affects flexures). *Filaggrin gene mutation* - **TRUE statement** - **Ichthyosis vulgaris** is caused by **loss-of-function mutations** in the **FLG gene** encoding **filaggrin**. - Filaggrin is essential for skin barrier function; its deficiency leads to dry, scaly skin with a defective epidermal barrier. - This is the most common inherited disorder of keratinization. *Ichthyosis* - **TRUE statement** - The clinical presentation (fish-like scales, onset after infancy, worsening in cold weather, positive family history) is classic for **ichthyosis vulgaris**. - The autosomal dominant inheritance pattern (both male and female siblings affected) confirms this diagnosis.

Q: All are true about the lesion shown except:

Predominantly occurs on genitals. ***Predominantly occurs on genitals*** - The image shows a rash consistent with **Pityriasis rosea**, which typically affects the **trunk and proximal extremities**, sparing the face, palms, and soles. - While individual lesions can appear anywhere on the body, the generalized distribution seen here is **not typically genital-predominant**. *HHV-7* - **Pityriasis rosea** is strongly associated with active infection or reactivation of **human herpesvirus 7 (HHV-7)**, and sometimes HHV-6. - Research suggests a causal link, although the exact pathogenic mechanism is still being investigated. *Herald patch* - **Pityriasis rosea** typically begins with a solitary, larger lesion known as a **herald patch** or mother patch, which precedes the generalized eruption by several days or weeks. - This initial lesion is often oval or circular and can be mistaken for other skin conditions. *Spontaneous healing* - **Pityriasis rosea** is a self-limiting rash that usually resolves spontaneously within **6-8 weeks** without specific treatment. - Although the rash can be itchy, the prognosis is excellent, and it rarely recurs.

Q: Identify which of the following tests is being done?

Diascopy. ***Diascopy*** - The image shows a glass slide or a transparent object being pressed against a skin lesion to observe changes in color and **vascular blanching**, which is characteristic of diascopy. - This diagnostic technique helps differentiate between **erythema caused by vasodilation** (which blanches) and **erythema caused by extravasated red blood cells,** such as in purpura (which does not blanch). *Pathergy Test* - The pathergy test involves **pricking the skin with a sterile needle** and observing the development of a papule or pustule at the site after 24-48 hours. - This test is primarily used to diagnose **Behçet's disease** and is not represented by the action shown in the image. *Patch test* - A patch test is used to diagnose **allergic contact dermatitis** by applying specific allergens to the skin under patches for 48 hours and then observing the reaction. - It does not involve pressing a glass slide against a lesion as depicted in the image. *Dermoscopy* - Dermoscopy is a non-invasive technique that uses a handheld device with magnification and a light source to examine skin lesions, particularly moles, for patterns indicative of **melanoma** or other skin cancers. - It involves direct visualization through a dermoscope, not simple pressure with a glass slide.

Q: A patient with pancreatic tumor and impaired glucose tolerance is having these lesions on flexural areas. What is the diagnosis?

Necrolytic migratory erythema. ***Necrolytic migratory erythema*** - This rash is characterized by **migratory, erythematous patches with central blistering, erosion, and crusting**, often seen in the **flexural areas** (groin, perineum, perioral region) and is highly suggestive of **glucagonoma**. - The combination of a **pancreatic tumor** (implying a possible glucagonoma) and **impaired glucose tolerance** (due to glucagon's diabetogenic effects) strongly points to this diagnosis. *Acanthosis Nigricans* - Characterized by **velvety, hyperpigmented plaques** typically found on the neck, axillae, and groin. - While it can be associated with insulin resistance and malignancy, its morphology is distinct from the erosive, migratory lesions shown, and the presence of a pancreatic tumor with impaired glucose tolerance points away from this being the primary diagnosis. *Toxic epidermal necrolysis* - This is a severe, life-threatening drug reaction characterized by **widespread epidermal necrosis and detachment**, resembling a severe burn, not the migratory, less extensive lesions seen here. - It rapidly affects a large body surface area and is typically preceded by drug exposure. *Necrobiosis lipoidica Diabeticorum* - This condition is typically associated with **diabetes mellitus** and presents as **yellowish, atrophic plaques with telangiectasias**, often on the shins. - Its appearance is distinct from the erythematous, migratory, and erosive lesions shown, and the clinical context of a pancreatic tumor points to glucagonoma syndrome.

Q: All are causes of the skin lesion shown except:

Chronic renal failure. ***Chronic renal failure*** - The image depicts **erythema multiforme**, a hypersensitivity reaction characterized by **target lesions**. - **Chronic renal failure** is not a known direct cause of erythema multiforme. *Infectious mononucleosis* - **Viral infections**, including **Epstein-Barr virus** (which causes infectious mononucleosis), are common triggers for erythema multiforme. - The immune response to the viral infection can lead to the characteristic skin lesions. *Mycoplasma* - **Mycoplasma pneumoniae infection** is a well-established cause of erythema multiforme, particularly in children and young adults. - Mycoplasma is one of the most common infectious triggers and can also cause other severe mucocutaneous reactions. *Collagen vascular disease* - Certain **collagen vascular diseases**, such as **systemic lupus erythematosus**, can be associated with erythema multiforme. - The underlying autoimmune dysregulation can trigger generalized hypersensitivity reactions.

Question 1

These lesions are seen in which of the following?

Accepted Answer

Erythema nodosum

Answer

Erythema infectiosum

Answer

Erythema induratum

Answer

Erythema multiforme

Question 2

A 65-year-old patient presents with development of multiple papules and nodules around the right knee for last one year. Which of the following hyper-lipoproteinemia is associated with this condition?

Accepted Answer

Type III Hyper-lipoproteinemia

Answer

Type I Hyper-lipoproteinemia

Answer

Type II Hyper-lipoproteinemia

Answer

Type IV Hyper-lipoproteinemia

Question 3

A 55-year-old patient presented with following lesions on his buttock. He consulted a general physician who diagnosed it as an allergy, but lesions are persisting. His blood sample was drawn and shows a creamy top layer. What is the diagnosis?

Accepted Answer

Eruptive xanthoma

Answer

Tuberous xanthoma

Answer

Tendinous xanthoma

Answer

Xanthelasma palpebrarum

Question 4

The following skin lesion can be seen in all except:

Accepted Answer

Normolipidemia

Answer

Type III hyperlipidemia

Answer

Diabetes mellitus

Answer

Secondary biliary cirrhosis

Question 5

A 26-year-old male presents with greasy papules on face and chest that feel like sandpaper. Palms and soles have minute pits. Skin biopsy was performed. What is the diagnosis?

Accepted Answer

Darier's disease

Answer

Hailey Hailey disease

Answer

Epidermolysis bullosa

Answer

Incontinentia pigmenti

Question 6

This is the clinical presentation of a 5-year-old boy with lesions worsening in cold weather. His mother says these lesions developed after 1 year of age. His sister has same lesions which developed after 2 years of age. All are true about the condition except:

Accepted Answer

Steroid sulfatase defect

Answer

Flexural sparing

Answer

Filaggrin gene mutation

Answer

Ichthyosis

Question 7

All are true about the lesion shown except:

Accepted Answer

Predominantly occurs on genitals

Answer

HHV-7

Answer

Herald patch

Answer

Spontaneous healing

Question 8

Identify which of the following tests is being done?

Accepted Answer

Diascopy

Answer

Pathergy Test

Answer

Patch test

Answer

Dermoscopy

Question 9

A patient with pancreatic tumor and impaired glucose tolerance is having these lesions on flexural areas. What is the diagnosis?

Accepted Answer

Necrolytic migratory erythema

Answer

Acanthosis Nigricans

Answer

Toxic epidermal necrolysis

Answer

Necrobiosis lipoidica Diabeticorum

Question 10

All are causes of the skin lesion shown except:

Accepted Answer

Chronic renal failure

Answer

Infectious mononucleosis

Answer

Mycoplasma

Answer

Collagen vascular disease

Basic Dermatology — MCQs

Basic Dermatology — MCQs

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