Basic Dermatology Practice Questions

Q: Primary skin lesions are seen in all except:

Bowen's disease. ***Bowen's disease*** - Bowen's disease is **squamous cell carcinoma in situ** presenting as erythematous, scaly patches or plaques - While morphologically it presents as patches/plaques (which are primary lesions by definition), it is considered the answer here because: - The lesion represents **neoplastic transformation** rather than a purely inflammatory primary skin change - In some dermatology teaching contexts, neoplastic lesions are distinguished from "true" primary inflammatory dermatoses - This distinction is **conceptual rather than morphological** *Lichen planus* - Presents with **polygonal, flat-topped, violaceous papules and plaques** - classic **primary skin lesions** - These are **inflammatory primary lesions** arising de novo on the skin - Wickham's striae may be visible on the surface *Psoriasis* - Characterized by **well-demarcated erythematous plaques** with silvery scales - definitive **primary skin lesions** - Plaques are the primary morphology, scales are secondary change - Arises from keratinocyte hyperproliferation and inflammatory changes *Reiter's syndrome* - Also known as **reactive arthritis** - Manifests with **circinate balanitis** (erosions with serpiginous borders) and **keratoderma blennorrhagicum** (hyperkeratotic papules/plaques) - These are **primary inflammatory skin lesions** occurring as part of the syndrome

Q: A skin condition unique to Chronic Kidney Disease patients:

Nephrogenic fibrosing dermopathy. ***Nephrogenic fibrosing dermopathy*** - Also known as **Nephrogenic Systemic Fibrosis (NSF)**, this condition is **exclusively seen in patients with renal insufficiency**, particularly those exposed to gadolinium-based contrast agents - Presents with **painful, woody induration and thickening of the skin**, often accompanied by joint contractures - This is the **only skin condition uniquely associated with chronic kidney disease** *Scleromyxedema* - A rare chronic skin disease characterized by **generalized papular and sclerodermoid skin lesions**, often associated with **monoclonal gammopathy** - **Not uniquely associated with renal disease**, although it may rarely occur in patients with kidney dysfunction *Calcinosis cutis* - Involves **deposition of calcium salts in the skin and subcutaneous tissues** - Can occur in various conditions causing hypercalcemia or tissue damage - While seen in patients with **end-stage renal disease** due to mineral and bone disorders, it is **not exclusive** to CKD (also occurs in CREST syndrome, dermatomyositis, hyperparathyroidism) *Norwegian scabies* - Also known as **crusted scabies**, a severe form characterized by widespread **hyperkeratotic crusts** and massive mite infestation - Primarily affects **immunocompromised individuals**, elderly, or those with neurological impairments - **Not specific to chronic kidney disease**

Q: An 85-year-old male cigar smoker with no notable medical history presented with black discoloration and hairy appearance of the tongue, which had lasted several years. He said he did not use bismuth-containing compounds. This condition could be treated with all of the following except:

Topical antibiotics. ***Topical antibiotics*** - The presented condition, **hairy black tongue (lingua villosa nigra)**, is often a benign condition caused by **hypertrophy of the filiform papillae** and is generally not related to bacterial infection. - While bacteria and fungi can contribute to the discoloration, **topical antibiotics** are not a primary treatment and would be ineffective against the underlying papillary hypertrophy. *Discontinuing smoking* - **Smoking** is a well-known risk factor for **hairy black tongue** as it can promote the accumulation of keratin on the filiform papillae. - Quitting smoking can help resolve the condition by reducing the irritants that contribute to its development. *Applying topical retinoids* - **Topical retinoids** can aid in the **exfoliation of keratinized cells** and promote normal epithelial differentiation. - This can help reduce the hyperkeratosis of the filiform papillae associated with **hairy black tongue**. *Application of 40 percent urea* - **Urea** is a **keratolytic agent** that can help soften and loosen the thickened keratinized layer on the tongue. - Application of **40% urea** can facilitate the removal of the elongated filiform papillae and the trapped debris, improving the appearance of hairy black tongue.

Q: Which of the following is true about Dyskeratosis congenita?

Nail dystrophy. ***Nail dystrophy*** - **Nail dystrophy** (thin, brittle, ridged, or absent nails) is one of the **classic mucocutaneous triad** of Dyskeratosis congenita. - It is a **key diagnostic feature**, often presenting early in childhood and seen in nearly all patients. - This is the **MOST characteristic** clinical feature among the options listed. *Hyperkeratosis* - Generalized **hyperkeratosis is NOT a characteristic feature** of Dyskeratosis congenita. - The typical skin changes are **reticulated hyperpigmentation** (lacy pigmentation on neck and chest), not hyperkeratosis. - This is the clearly **incorrect option**. *Leukoplakia* - **Oral leukoplakia** is indeed a true feature and part of the classic mucocutaneous triad. - However, it may appear later than nail changes and is not always present in early disease. - While true, **nail dystrophy is more consistently present** and remains the best single answer. *Pancytopenia* - **Bone marrow failure with pancytopenia** is a major complication occurring in 80-90% of patients. - However, it typically develops **later in life** (teens to early adulthood), whereas nail dystrophy presents earlier. - As a systemic complication rather than a direct mucocutaneous manifestation, nail dystrophy remains the more characteristic diagnostic feature for clinical identification.

Q: Wood's lamp is used in the diagnosis of:

All of the options. ***All of the options*** - Wood's lamp is a diagnostic tool that uses **ultraviolet light (UV-A at 365 nm)** to detect certain skin conditions by observing characteristic fluorescence patterns. - All three conditions listed show distinctive features under Wood's lamp examination, making this an important diagnostic tool in dermatology. **P. versicolor (Pityriasis versicolor)** - Shows characteristic **yellow-green to golden-orange fluorescence** under Wood's lamp - This fluorescence is due to metabolites produced by *Malassezia* yeast species - Helps confirm diagnosis and delineate the extent of lesions, especially on darker skin **Vitiligo** - Depigmented areas appear as **bright, stark white patches** with sharp borders under UV light - Wood's lamp accentuates areas of **complete melanin loss**, making subtle lesions more visible - Particularly useful for detecting vitiligo on fair skin where lesions may not be clinically apparent - Helps differentiate vitiligo from other hypopigmented conditions **Porphyria** - In **porphyria cutanea tarda (PCT)** and **congenital erythropoietic porphyria (CEP)**, Wood's lamp detects **coral-red to pink-orange fluorescence** - Fluorescence is seen in urine (containing porphyrins), teeth, and sometimes skin lesions - This occurs due to accumulation of **porphyrins**, which are photosensitive compounds that fluoresce under UV light - Useful screening tool for suspected porphyria cases

Q: Miliaria is a disorder of-

Eccrine glands. ***Eccrine glands*** - **Miliaria**, commonly known as prickly heat or heat rash, is a skin condition that results from the obstruction of the **eccrine sweat ducts**. - This obstruction leads to the leakage of sweat into the epidermis or dermis, causing inflammatory reactions and characteristic lesions. *Holocrine glands* - **Holocrine glands** secrete their entire cell contents, including disintegrated cells, as part of their secretory product. - The **sebaceous glands** are an example of holocrine glands, and their dysfunction is not the primary cause of miliaria. *Sebaceous glands* - **Sebaceous glands** produce **sebum**, an oily substance that lubricates the skin and hair. - Disorders of sebaceous glands include **acne**, not miliaria, which is related to sweat production. *Apocrine glands* - **Apocrine glands** are a type of sweat gland found in specific areas like the axilla and anogenital region, and their secretions are typically odorless until broken down by bacteria. - **Miliaria** is not associated with the dysfunction or obstruction of apocrine glands.

Q: Mouth lesions are seen in:

Lichen Planus. ***Lichen Planus*** - **Oral lichen planus** often presents with characteristic **white, lacy patterns (Wickham's striae)** on the buccal mucosa, tongue, or gingiva. - These lesions can be painful, erosive, or reticular, and are considered a **classic and common manifestation** of the disease. - Oral involvement occurs in **50-70% of lichen planus cases**, making it the most characteristic answer. *Ichthyosis Vulgaris* - This condition is primarily characterized by **dry, scaly skin**, especially on the extremities, due to a problem with keratinization. - **Mouth lesions are not a feature** of ichthyosis vulgaris as it does not affect mucous membranes. *Psoriasis* - While psoriasis primarily affects the skin with **erythematous plaques and silvery scales**, oral manifestations can occur but are **less specific and less common** than in lichen planus. - Associated oral findings include **geographic tongue (benign migratory glossitis)** and fissured tongue, but these are not pathognomonic. - True **oral psoriatic plaques** are rare and non-specific compared to the characteristic Wickham's striae of lichen planus. *Basal Cell CA* - **Basal cell carcinoma (BCC)** is a common skin cancer that rarely appears in the oral cavity. - When it does, it usually presents as a lesion on the **lips** (especially the lower lip at the vermillion border) but is primarily a cutaneous malignancy. - **Not associated with widespread oral mucosal lesions**.

Q: Koebner's phenomenon is seen in all of the following except:

Erythema multiforme. ***Erythema multiforme*** - **Erythema multiforme** is an acute hypersensitivity reaction that does **NOT** typically demonstrate the Koebner phenomenon. - Unlike chronic papulosquamous disorders, EM lesions arise from immunologic triggers (infections, drugs) rather than trauma-induced spread. - The characteristic **target lesions** develop in response to antigenic stimuli, not mechanical trauma. *Darier's disease* - **Darier's disease** (keratosis follicularis) is an autosomal dominant disorder that exhibits the Koebner phenomenon. - New keratotic papules develop at sites of trauma, scratching, or friction. - This trauma-induced lesion development is a **key clinical feature** of the disease. *Molluscum contagiosum* - **Molluscum contagiosum** demonstrates the Koebner phenomenon through **autoinoculation**. - Scratching can cause viral spread, resulting in **linear arrangements of lesions** along scratch marks. - This is a classic example of trauma-induced spread in viral skin infections. *Scleromyxedema* - **Scleromyxedema** (generalized lichen myxedematosus) can exhibit the Koebner phenomenon. - New papules may develop at sites of trauma in some cases. - While less commonly emphasized than in psoriasis or lichen planus, Koebnerization has been reported in this condition.

Q: "Isomorphic response" can be a feature of the following except

Tinea. ***Tinea*** - The **isomorphic response (Koebner phenomenon)** refers to the development of new skin lesions in areas of trauma due to an immunological process. - This phenomenon is **not typically seen in tinea** (fungal infections). - While tinea can spread to new areas, this occurs through **direct fungal inoculation and contact spread**, not through the true Koebner mechanism. *Warts* - **Warts** caused by human papillomavirus (HPV) can exhibit the **isomorphic response**. - Trauma to the skin can lead to **viral inoculation** in that area, resulting in new wart formation along lines of trauma. - This is a well-recognized example of Koebner phenomenon in viral infections. *Molluscum contagiosum* - **Molluscum contagiosum** (poxvirus infection) can demonstrate the **isomorphic response**. - **Scratching or rubbing** can spread the virus to new areas through autoinoculation. - New lesions develop along the lines of trauma, consistent with Koebner phenomenon. *Psoriasis* - **Psoriasis** is the **classic and most well-known** condition exhibiting the isomorphic response or Koebner phenomenon. - New psoriatic plaques appear in areas of **skin injury** (scratches, cuts, burns, surgical incisions, friction). - Seen in approximately **25-50%** of psoriasis patients.

Q: Which of the following is true about Pityriasis rubra pilaris?

Isolated patches of normal skin are found. ***Isolated patches of normal skin are found*** - This characteristic, known as **"islands of sparing"** or **"skip areas"**, is a hallmark clinical feature of Pityriasis rubra pilaris (PRP), where small patches of unaffected skin are seen within widespread erythematous and scaling plaques. - These spared areas help differentiate PRP from other generalized erythematous skin conditions. *Oral cyclosporine is the drug of choice* - While systemic retinoids (e.g., **acitretin**) are often considered first-line systemic therapy for Pityriasis rubra pilaris, cyclosporine is a second-line option for severe, refractory cases. - **Corticosteroids** and **methotrexate** are also used, but there is no single drug of choice; treatment is often individualized based on disease severity. *Common in females* - Pityriasis rubra pilaris does not show a significant gender predilection and affects **males and females equally**. - Its incidence is generally rare, making gender-specific prevalence less notable than in some other dermatological conditions. *Occurs mainly in adults* - Pityriasis rubra pilaris has a **bimodal age distribution**, with peaks in incidence during **childhood** (juvenile form, often localized) and in **adulthood** (classical adult form, more generalized). - Therefore, stating it occurs *mainly* in adults is inaccurate as a significant proportion of cases occur in children.

Question 1

Primary skin lesions are seen in all except:

Accepted Answer

Bowen's disease

Answer

Lichen planus

Answer

Psoriasis

Answer

Reiter's syndrome

Question 2

A skin condition unique to Chronic Kidney Disease patients:

Accepted Answer

Nephrogenic fibrosing dermopathy

Answer

Scleromyxedema

Answer

Calcinosis cutis

Answer

Norwegian scabies

Question 3

An 85-year-old male cigar smoker with no notable medical history presented with black discoloration and hairy appearance of the tongue, which had lasted several years. He said he did not use bismuth-containing compounds. This condition could be treated with all of the following except:

Accepted Answer

Topical antibiotics

Answer

Discontinuing smoking

Answer

Applying topical retinoids

Answer

Application of 40 percent urea

Question 4

Which of the following is true about Dyskeratosis congenita?

Accepted Answer

Nail dystrophy

Answer

Hyperkeratosis

Answer

Leukoplakia

Answer

Pancytopenia

Question 5

Wood's lamp is used in the diagnosis of:

Accepted Answer

All of the options

Answer

P. versicolor

Answer

Vitiligo

Answer

Porphyria

Question 6

Miliaria is a disorder of-

Accepted Answer

Eccrine glands

Answer

Holocrine glands

Answer

Sebaceous glands

Answer

Apocrine glands

Question 7

Mouth lesions are seen in:

Accepted Answer

Lichen Planus

Answer

Ichthyosis Vulgaris

Answer

Psoriasis

Answer

Basal Cell CA

Question 8

Koebner's phenomenon is seen in all of the following except:

Accepted Answer

Erythema multiforme

Answer

Darier's disease

Answer

Molluscum contagiosum

Answer

Scleromyxedema

Question 9

"Isomorphic response" can be a feature of the following except

Accepted Answer

Tinea

Answer

Warts

Answer

Molluscum contagiosum

Answer

Psoriasis

Question 10

Which of the following is true about Pityriasis rubra pilaris?

Accepted Answer

Isolated patches of normal skin are found

Answer

Oral cyclosporine is the drug of choice

Answer

Common in females

Answer

Occurs mainly in adults

Basic Dermatology — MCQs

Basic Dermatology — MCQs

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