Basic Dermatology Practice Questions

Q: Epidermal turnover time in healthy adults is

4 weeks. ***4 weeks*** - The **epidermal turnover time** refers to the period it takes for cells produced in the stratum basale to migrate to the stratum corneum and be shed. - In healthy adults, this process generally takes about **28 to 30 days**, which is approximately 4 weeks. *2 weeks* - A turnover time of 2 weeks would indicate a significantly **accelerated epidermal proliferation**, typically seen in conditions like **psoriasis**. - This rapid turnover does not allow for proper keratinization and leads to incomplete differentiation of keratinocytes. *6 weeks* - A 6-week turnover time would signify a **slower-than-normal epidermal renewal**, which could be associated with conditions involving **reduced cellular activity** or metabolic slowdown. - This extended period is not characteristic of healthy epidermal homeostasis. *8 weeks* - An 8-week turnover time represents an even **more prolonged epidermal regeneration** process. - Such a long duration would imply significant impairment in cellular proliferation and differentiation, which is not found in healthy skin.

Q: Thickening of the epidermis and/or dermis is

Lichenification. ***Lichenification*** - **Lichenification** is the correct answer as it involves thickening of **both the epidermis (acanthosis)** and **dermis (fibrosis)**, which directly matches the question asking for thickening of "epidermis and/or dermis" - Characterized by leathery thickening with exaggerated skin markings - Results from chronic scratching or rubbing leading to epidermal hyperplasia and dermal fibrosis *Hyperkeratosis* - **Hyperkeratosis** refers only to thickening of the **stratum corneum** (the outermost keratinized layer), not the entire epidermis or dermis - It is limited to increased keratin in the cornified layer - Does not involve the full thickness of epidermis or any dermal thickening *Callus* - A **callus** is a localized form of hyperkeratosis affecting only the stratum corneum - Forms in response to repeated friction or pressure - Represents localized thickening, not generalized epidermal or dermal thickening *Scaling* - **Scaling** refers to visible shedding or flaking of dead skin cells from the stratum corneum - It is a descriptive term for desquamation, not thickening - Does not indicate epidermal or dermal thickening

Q: All of the following are not true with respect to erythema multiforme except?

Targetoid lesions are seen. ***Targetoid lesions are seen*** - **Erythema multiforme (EM)** is characterized by distinctive **targetoid lesions** (target lesions) with three concentric zones: a dusky center, a pale middle ring, and an erythematous outer ring. - These lesions are a hallmark of EM and differentiate it from many other dermatological conditions. *Most commonly due to leukemia* - **Erythema multiforme** is most commonly associated with **infections**, particularly **herpes simplex virus (HSV)**, rather than leukemia. - Other common triggers include **mycoplasma infections** and certain **medications**. *Steroids are the drug of choice* - For typical, mild **erythema multiforme**, **topical steroids** may be used for symptomatic relief, but they are generally **not the drug of choice** for severe or widespread disease. - **Systemic steroids** are controversial and not routinely recommended for uncomplicated EM, as they may prolong the course or lead to recurrences, though they might be considered in severe cases or to prevent progression to Stevens-Johnson syndrome. *Koebner's phenomenon is seen* - The **Koebner phenomenon** (isomorphic response), where new lesions appear at sites of trauma, is classically associated with conditions like **psoriasis**, **lichen planus**, and **vitiligo**. - It is **not typically seen** in erythema multiforme.

Q: Dermatological manifestation of which of the following diseases?

Pellagra. ***Pellagra*** - The image shows **Casal's necklace**, a characteristic **hyperpigmented, scaly, photosensitive rash** around the neck area, which is pathognomonic for pellagra. - Pellagra is caused by **niacin (vitamin B3) deficiency** and presents with the classic "4 D's": **dermatitis**, **diarrhea**, **dementia**, and **death** if untreated. *Acrodermatitis enteropathica* - This is a **hereditary zinc deficiency disorder** that presents with **periorificial and acral dermatitis** (around body openings and extremities). - The skin lesions are typically **vesiculobullous or eczematous** with a different distribution pattern, not the characteristic neck involvement seen here. *Photo dermatitis* - This is a **general term** for skin inflammation caused by **light exposure** and not a specific disease entity. - While pellagra does cause photosensitive dermatitis, photodermatitis alone doesn't explain the specific **necklace-like distribution** and underlying nutritional deficiency. *Vitamin B deficiency* - This option is **too broad** and non-specific, as it encompasses multiple B vitamin deficiencies with different manifestations. - Other B vitamin deficiencies like **B2 (riboflavin)** or **B6 (pyridoxine)** cause **angular cheilitis** and **seborrheic dermatitis**, not the characteristic neck rash of pellagra.

Q: Which is TRUE about dermatologic emergencies?

DRESS syndrome needs immediate drug cessation. **DRESS syndrome needs immediate drug cessation** - **Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)** is a severe hypersensitivity reaction requiring immediate identification and withdrawal of the causative drug to prevent multi-organ failure. - Continuation of the offending drug can lead to worsening symptoms and potentially fatal outcomes due to progressive organ damage. *Pyoderma gangrenosum needs urgent debridement* - **Pyoderma gangrenosum (PG)** is a **neutrophilic dermatosis** characterized by painful, rapidly enlarging ulcers. - **Debridement** of PG lesions is generally **contraindicated** as it can worsen the ulceration through **pathergy**, a phenomenon where minor trauma induces new lesions. *TEN requires immediate systemic steroids* - **Toxic Epidermal Necrolysis (TEN)** is a life-threatening skin reaction characterized by widespread epidermal detachment. - While controversy exists, **systemic corticosteroids** are generally **not recommended** in TEN due to potential for increased infection risk and delayed re-epithelialization without clear evidence of benefit. *Calciphylaxis treatment focuses on wound care* - While **wound care** is a crucial component of **calciphylaxis** management, it is not the sole focus. - **Calciphylaxis** treatment also includes aggressive measures to reduce **calcium-phosphate product**, manage pain, and address underlying conditions such as **end-stage renal disease**.

Q: Patient on anti-TB drugs develops tender nodules on shins. Most likely diagnosis is:

Erythema nodosum. ***Erythema nodosum*** - Erythema nodosum is a common **cutaneous adverse drug reaction** to anti-TB medications, presenting with **tender, erythematous nodules** typically on the shins. - It is a form of **panniculitis** (inflammation of subcutaneous fat) specifically associated with various triggers, including infections and drugs, making it highly probable in this context. *Sweet syndrome* - Sweet syndrome (acute febrile neutrophilic dermatosis) presents with **tender, erythematous plaques and nodules** often associated with fever and leukocytosis. - While it can be drug-induced, it typically involves a more widespread skin eruption and prominent systemic symptoms like **fever**, which are not specified here. *Panniculitis* - Panniculitis is a general term for **inflammation of the subcutaneous fat**, and erythema nodosum is a type of panniculitis. - This option is too broad; while accurate, "Erythema nodosum" is the **most specific and likely diagnosis** given the patient’s presentation in the context of anti-TB drug use. *Erythema multiforme* - Erythema multiforme is characterized by **target lesions** (concentric rings of erythema and edema) and often involves mucous membranes. - The description of **tender nodules on shins** does not fit the characteristic morphology of erythema multiforme.

Q: All are true about lichen planus EXCEPT:

Spares oral mucosa. ***Spares oral mucosa*** - This statement is incorrect because **lichen planus frequently involves the oral mucosa**, presenting as white reticular lesions, erosions, or plaques. - Oral involvement is common and can be the only manifestation of lichen planus. *Wickham's striae present* - **Wickham's striae** are characteristic **white, lacy reticular patterns** seen on the surface of lichen planus lesions, especially on the oral mucosa and cutaneous papules. - Their presence is a classic diagnostic feature of lichen planus. *Violaceous flat papules* - Cutaneous lesions of lichen planus are typically described as **pruritic, polygonal, planar (flat-topped), purple (violaceous) papules and plaques**. - This classic description helps in the clinical diagnosis of the condition. *Koebner phenomenon positive* - The **Koebner phenomenon**, or isomorphic response, refers to the development of new skin lesions in areas of trauma or injury. - This phenomenon is often observed in lichen planus, where scratching or irritation can precipitate new lesions along the lines of trauma.

Q: Which of the following is a typical feature of erythema multiforme?

Target lesions. ***Target lesions*** - **Target lesions**, characterized by concentric rings of varying color (like a "bulls-eye"), are the hallmark dermatological finding in **erythema multiforme**. - These lesions typically appear suddenly, often on the **extremities**, and can be associated with pruritus or burning. *Vesicular eruption* - While vesicles can be seen in some severe forms of erythema multiforme, a **generalized vesicular eruption** is more characteristic of conditions like **herpes simplex infection**, varicella, or shingles. - The primary lesion in typical erythema multiforme is the target lesion, not widespread vesicles. *Nikolsky sign* - The **Nikolsky sign**, which is the dislodging of epidermis by lateral pressure on apparently uninvolved skin, is typically associated with **blistering disorders** like **pemphigus vulgaris** or **toxic epidermal necrolysis (TEN)**. - It is not a feature of erythema multiforme, where the epidermal detachment is usually localized and not easily induced by gentle pressure on healthy skin. *Comedonal lesions* - **Comedonal lesions** (blackheads and whiteheads) are characteristic features of **acne vulgaris**. - They result from blocked pilosebaceous units and are fundamentally different in pathogenesis and appearance from the inflammatory lesions seen in erythema multiforme.

Q: A 20-year-old woman presents with the sudden onset of red, target-shaped lesions on her palms and soles, following a herpes simplex outbreak. What is the likely diagnosis?

Erythema multiforme (EM). ***Erythema multiforme (EM)*** - This presentation is classic for **Erythema multiforme**, characterized by the acute onset of **target-shaped lesions** on the extremities, often precipitated by **herpes simplex virus (HSV) infection**. - The lesions on the **palms and soles** are a hallmark feature, distinguishing it from other skin conditions. *Stevens-Johnson syndrome (SJS)* - While SJS also involves skin lesions, it is a much more severe condition characterized by **extensive epidermal detachment** (often >10% of body surface area) and significant **mucosal involvement**. - SJS typically involves flu-like prodromal symptoms and is more commonly associated with drug reactions rather than HSV. *Pemphigus vulgaris (PV)* - Pemphigus vulgaris is an **autoimmune blistering disease** causing **flaccid bullae** and erosions on the skin and mucous membranes, often with Nikolsky's sign. - It does not typically present with target lesions nor is it triggered by HSV outbreaks. *Urticaria (hives)* - Urticaria presents as **transient, pruritic, raised wheals** (hives) that can appear anywhere on the body and blanch with pressure. - Unlike erythema multiforme, urticaria lesions are not typically target-shaped and do not commonly persist for days.

Question 1

Epidermal turnover time in healthy adults is

Accepted Answer

4 weeks

Answer

2 weeks

Answer

6 weeks

Answer

8 weeks

Question 2

Thickening of the epidermis and/or dermis is

Accepted Answer

Lichenification

Answer

Callus

Answer

Scaling

Answer

Hyperkeratosis

Question 3

All of the following are not true with respect to erythema multiforme except?

Accepted Answer

Targetoid lesions are seen

Answer

Most commonly due to leukemia

Answer

Steroids are the drug of choice

Answer

Koebner's phenomenon is seen

Question 4

Dermatological manifestation of which of the following diseases?

Accepted Answer

Pellagra

Answer

Photo dermatitis

Answer

Acrodermatitis enteropathica

Answer

Vitamin B deficiency

Question 5

Which is TRUE about dermatologic emergencies?

Accepted Answer

DRESS syndrome needs immediate drug cessation

Answer

Pyoderma gangrenosum needs urgent debridement

Answer

TEN requires immediate systemic steroids

Answer

Calciphylaxis treatment focuses on wound care

Question 6

A 35-year-old female presents with recurrent painful nodules on shins, associated with fever and arthralgia. Previous biopsy showed septal panniculitis. She's now pregnant at 20 weeks. Most appropriate treatment is:

Accepted Answer

Prednisone

Answer

Colchicine

Answer

Potassium iodide

Answer

Indomethacin

Question 7

Patient on anti-TB drugs develops tender nodules on shins. Most likely diagnosis is:

Accepted Answer

Erythema nodosum

Answer

Sweet syndrome

Answer

Panniculitis

Answer

Erythema multiforme

Question 8

All are true about lichen planus EXCEPT:

Accepted Answer

Spares oral mucosa

Answer

Wickham's striae present

Answer

Violaceous flat papules

Answer

Koebner phenomenon positive

Question 9

Which of the following is a typical feature of erythema multiforme?

Accepted Answer

Target lesions

Answer

Vesicular eruption

Answer

Nikolsky sign

Answer

Comedonal lesions

Question 10

A 20-year-old woman presents with the sudden onset of red, target-shaped lesions on her palms and soles, following a herpes simplex outbreak. What is the likely diagnosis?

Accepted Answer

Erythema multiforme (EM)

Answer

Stevens-Johnson syndrome (SJS)

Answer

Pemphigus vulgaris (PV)

Answer

Urticaria (hives)

Basic Dermatology — MCQs

Basic Dermatology — MCQs

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