UPSC-CMS 2025 — Dermatology

Q: A 40 year old man with a known case of chronic pancreatitis presents to the OPD with complaint of skin pigmentation over the abdomen. The patient gives a history of chronic use of a hot water bottle to relieve the abdominal discomfort. Which one of the following is the most appropriate diagnosis?

Erythema ab igne. ***Erythema ab igne*** - This condition is caused by **chronic exposure to moderate heat**, which aligns with the patient's history of using a hot water bottle for abdominal discomfort. - It presents as **reticulated erythema** and **hyperpigmentation** on the affected skin, precisely matching the description of skin pigmentation over the abdomen. *Erythema infectiosum* - This is also known as **Fifth disease** and is caused by **Parvovirus B19**. - It typically presents with a characteristic **"slapped cheek" rash** on the face and a lacy rash on the trunk and limbs, which is not consistent with the patient's presentation. *Erythema marginatum* - This is a rare, transient rash associated with **acute rheumatic fever**. - It presents as **pink-red macules with clear centers and serpiginous borders** that migrate, which does not fit the described chronic pigmentation. *Erythema nodosum* - This condition is characterized by **tender, red nodules** typically found on the **shins**. - It is a form of **panniculitis** (inflammation of subcutaneous fat) and is not caused by chronic heat exposure, nor does it present as diffuse pigmentation. [Practice more Dermatology PYQs on OnCourse]

Q: Which one of the following is the correct description of Mee's lines, seen in chronic arsenic poisoning?

Transverse white lines on nails of fingers and toes. ***Transverse white lines on nails of fingers and toes*** - **Mee's lines** are characteristic **white transverse bands** seen specifically on the **nails** of the fingers and toes. - They are typically associated with **arsenic poisoning** but can also be seen in other systemic illnesses. *Transverse white lines on the skin of palms and soles* - While chronic arsenic poisoning can cause **skin pigmentation changes** (melanosis) and **hyperkeratosis** on the palms and soles, it does not typically manifest as distinct white transverse lines on the skin. - Mee's lines are exclusively a **nail finding**. *Transverse red lines on the nails of fingers and toes* - **Red lines on nails** are not characteristic of Mee's lines; Mee's lines are described as **white**. - Red nail changes, such as splinter hemorrhages, are often associated with other conditions, like **endocarditis**. *Transverse red lines on the skin of palms and soles* - This description does not correspond to Mee's lines, which are **white nail changes**, nor is it a typical manifestation of chronic arsenic poisoning on the skin in this specific pattern. - Skin manifestations of arsenic poisoning on palms and soles are usually **hyperpigmentation** and **hyperkeratosis**. [Practice more Dermatology PYQs on OnCourse]

Q: A 56 year old gardener presents with an ulcerative nodule with purulent discharge on his right index finger. He had a prick with a thorn, at the same site around a month back. Which one of the following infections is most likely?

Sporotrichosis. ***Sporotrichosis*** - This presentation, an **ulcerative nodule with purulent discharge** on a finger after a **thorn prick** in a gardener, is classic for **sporotrichosis** (rose gardener's disease). - The organism, *Sporothrix schenckii*, is found in soil, plants, and decaying vegetation and typically enters through **skin trauma**. *Chromoblastomycosis* - Characteristically presents with **verrucous (warty) plaques or nodules** that slowly enlarge; it does not typically show the ulcerative nodule with purulent discharge found here. - While it can be acquired through trauma, the **morphology of the lesions** differs from the described case. *Phaeohyphomycosis* - This is a broad term for infections caused by dematiaceous (pigmented) fungi that typically present as **subcutaneous cysts, abscesses, or nodules**, but the specific clinical picture of **lymphocutaneous spread** following trauma is less characteristic than sporotrichosis. - The lesions tend to be more **encapsulated or abscess-like** rather than the ulcerative, purulent nodule described. *Mycetoma* - Mycetoma presents as a **chronic, localized, progressively destructive infection** of the skin, subcutaneous tissue, fascia, and bone, often characterized by **swelling, draining sinuses, and grains** (microcolonies of the causative organism). - While it can be acquired via trauma, the typical presentation is much more **extensive and chronic** than the initial ulcerative nodule described. [Practice more Dermatology PYQs on OnCourse]

Q: Koebner phenomenon is seen in which one of the following conditions?

Psoriasis. ***Psoriasis*** - The **Koebner phenomenon**, or isomorphic response, is characteristic of psoriasis, where new psoriatic lesions appear on areas of **traumatized skin**. - This response is triggered by various forms of skin injury, such as scratches, surgical incisions, or sunburn. *Behçet's disease* - Behçet's disease is associated with **pathergy**, which is a hyper-reactivity to skin injury presenting as a sterile pustule or papule at the site of trauma, but it is distinct from the Koebner phenomenon. - While both involve skin reactivity to trauma, pathergy in Behçet's disease is typically a pustular response, whereas Koebner phenomenon in psoriasis results in typical psoriatic lesions. *Leprosy* - Leprosy is an infectious disease causing **skin lesions** and nerve damage, but it does not typically exhibit the Koebner phenomenon. - The skin manifestations in leprosy are primarily due to the infection with *Mycobacterium leprae* rather than an isomorphic response to trauma. *Acne Vulgaris* - Acne vulgaris is a common inflammatory skin condition involving hair follicles and sebaceous glands, characterized by **comedones, papules, pustules, and cysts**. - It is not associated with the Koebner phenomenon; new lesions arise from follicular blockage and inflammation, not from skin trauma in the same manner as psoriasis. [Practice more Dermatology PYQs on OnCourse]

6 Previous Year Questions with Answers & Explanations

Questions

A 40 year old man with a known case of chronic pancreatitis presents to the OPD with complaint of skin pigmentation over the abdomen. The patient gives a history of chronic use of a hot water bottle to relieve the abdominal discomfort. Which one of the following is the most appropriate diagnosis?

Which one of the following is the correct description of Mee's lines, seen in chronic arsenic poisoning?

Which one of the following statements is correct regarding leprosy?

A 56 year old gardener presents with an ulcerative nodule with purulent discharge on his right index finger. He had a prick with a thorn, at the same site around a month back. Which one of the following infections is most likely?

Koebner phenomenon is seen in which one of the following conditions?

Consider the following regarding the human hair growth cycle : I. Anagen is a phase of active hair growth II. Telogen is a transitional phase III. Catagen is a resting phase Which of the statements given above is/are correct?

UPSC-CMS 2025 - Dermatology UPSC-CMS Practice Questions and MCQs

Question 1: A 40 year old man with a known case of chronic pancreatitis presents to the OPD with complaint of skin pigmentation over the abdomen. The patient gives a history of chronic use of a hot water bottle to relieve the abdominal discomfort. Which one of the following is the most appropriate diagnosis?

A. Erythema infectiosum
B. Erythema marginatum
C. Erythema ab igne (Correct Answer)
D. Erythema nodosum

Explanation: ***Erythema ab igne*** - This condition is caused by **chronic exposure to moderate heat**, which aligns with the patient's history of using a hot water bottle for abdominal discomfort. - It presents as **reticulated erythema** and **hyperpigmentation** on the affected skin, precisely matching the description of skin pigmentation over the abdomen. *Erythema infectiosum* - This is also known as **Fifth disease** and is caused by **Parvovirus B19**. - It typically presents with a characteristic **"slapped cheek" rash** on the face and a lacy rash on the trunk and limbs, which is not consistent with the patient's presentation. *Erythema marginatum* - This is a rare, transient rash associated with **acute rheumatic fever**. - It presents as **pink-red macules with clear centers and serpiginous borders** that migrate, which does not fit the described chronic pigmentation. *Erythema nodosum* - This condition is characterized by **tender, red nodules** typically found on the **shins**. - It is a form of **panniculitis** (inflammation of subcutaneous fat) and is not caused by chronic heat exposure, nor does it present as diffuse pigmentation.

Question 2: Which one of the following is the correct description of Mee's lines, seen in chronic arsenic poisoning?

A. Transverse white lines on the skin of palms and soles
B. Transverse white lines on nails of fingers and toes (Correct Answer)
C. Transverse red lines on the nails of fingers and toes
D. Transverse red lines on the skin of palms and soles

Explanation: ***Transverse white lines on nails of fingers and toes*** - **Mee's lines** are characteristic **white transverse bands** seen specifically on the **nails** of the fingers and toes. - They are typically associated with **arsenic poisoning** but can also be seen in other systemic illnesses. *Transverse white lines on the skin of palms and soles* - While chronic arsenic poisoning can cause **skin pigmentation changes** (melanosis) and **hyperkeratosis** on the palms and soles, it does not typically manifest as distinct white transverse lines on the skin. - Mee's lines are exclusively a **nail finding**. *Transverse red lines on the nails of fingers and toes* - **Red lines on nails** are not characteristic of Mee's lines; Mee's lines are described as **white**. - Red nail changes, such as splinter hemorrhages, are often associated with other conditions, like **endocarditis**. *Transverse red lines on the skin of palms and soles* - This description does not correspond to Mee's lines, which are **white nail changes**, nor is it a typical manifestation of chronic arsenic poisoning on the skin in this specific pattern. - Skin manifestations of arsenic poisoning on palms and soles are usually **hyperpigmentation** and **hyperkeratosis**.

Question 3: Which one of the following statements is correct regarding leprosy?

A. Nose is the last site of involvement in lepromatous leprosy
B. Type 1 Leprosy Reaction is also called erythema nodosum leprosum
C. 'Lion face' appearance is seen in tuberculoid leprosy
D. Type 2 Leprosy Reaction is an immune complex mediated syndrome also known as erythema nodosum leprosum (Correct Answer)

Explanation: ***Type 2 Leprosy Reaction is an immune complex mediated syndrome also known as erythema nodosum leprosum*** - **Type 2 Leprosy Reaction (ENL)** is indeed an **immune complex-mediated hypersensitivity reaction** seen in cases of **multibacillary leprosy**, primarily **lepromatous leprosy** patients undergoing treatment. - It presents with painful, tender, red subcutaneous nodules, often associated with fever, malaise, arthralgia, and neuritis due to the deposition of **antigen-antibody complexes**. *Nose is the last site of involvement in lepromatous leprosy* - The **nose** is actually one of the **earliest sites of involvement** in **lepromatous leprosy** due to the preference of *Mycobacterium leprae* for cooler tissues. - Initial nasal involvement can lead to nasal stuffiness, epistaxis, and, in advanced stages, destruction of cartilage leading to a **saddle nose deformity**. *Type 1 Leprosy Reaction is also called erythema nodosum leprosum* - **Erythema Nodosum Leprosum (ENL)** is **Type 2 Leprosy Reaction**, not Type 1. - **Type 1 Leprosy Reaction** (also known as **reversal reaction**) is a **delayed-type hypersensitivity reaction** that typically occurs in borderline forms of leprosy, characterized by inflammation of existing skin lesions and nerves. *'Lion face' appearance is seen in tuberculoid leprosy* - The **"lion face" appearance (leontiasis)** is a characteristic feature of **advanced lepromatous leprosy**, not tuberculoid leprosy. - It results from diffuse skin infiltration, thickening of facial skin, and nodule formation, leading to coarse, pendulous folds and a distorted facial appearance.

Question 4: A 56 year old gardener presents with an ulcerative nodule with purulent discharge on his right index finger. He had a prick with a thorn, at the same site around a month back. Which one of the following infections is most likely?

A. Chromoblastomycosis
B. Phaeohyphomycosis
C. Mycetoma
D. Sporotrichosis (Correct Answer)

Explanation: ***Sporotrichosis*** - This presentation, an **ulcerative nodule with purulent discharge** on a finger after a **thorn prick** in a gardener, is classic for **sporotrichosis** (rose gardener's disease). - The organism, *Sporothrix schenckii*, is found in soil, plants, and decaying vegetation and typically enters through **skin trauma**. *Chromoblastomycosis* - Characteristically presents with **verrucous (warty) plaques or nodules** that slowly enlarge; it does not typically show the ulcerative nodule with purulent discharge found here. - While it can be acquired through trauma, the **morphology of the lesions** differs from the described case. *Phaeohyphomycosis* - This is a broad term for infections caused by dematiaceous (pigmented) fungi that typically present as **subcutaneous cysts, abscesses, or nodules**, but the specific clinical picture of **lymphocutaneous spread** following trauma is less characteristic than sporotrichosis. - The lesions tend to be more **encapsulated or abscess-like** rather than the ulcerative, purulent nodule described. *Mycetoma* - Mycetoma presents as a **chronic, localized, progressively destructive infection** of the skin, subcutaneous tissue, fascia, and bone, often characterized by **swelling, draining sinuses, and grains** (microcolonies of the causative organism). - While it can be acquired via trauma, the typical presentation is much more **extensive and chronic** than the initial ulcerative nodule described.

Question 5: Koebner phenomenon is seen in which one of the following conditions?

A. Behçet's disease
B. Leprosy
C. Acne Vulgaris
D. Psoriasis (Correct Answer)

Explanation: ***Psoriasis*** - The **Koebner phenomenon**, or isomorphic response, is characteristic of psoriasis, where new psoriatic lesions appear on areas of **traumatized skin**. - This response is triggered by various forms of skin injury, such as scratches, surgical incisions, or sunburn. *Behçet's disease* - Behçet's disease is associated with **pathergy**, which is a hyper-reactivity to skin injury presenting as a sterile pustule or papule at the site of trauma, but it is distinct from the Koebner phenomenon. - While both involve skin reactivity to trauma, pathergy in Behçet's disease is typically a pustular response, whereas Koebner phenomenon in psoriasis results in typical psoriatic lesions. *Leprosy* - Leprosy is an infectious disease causing **skin lesions** and nerve damage, but it does not typically exhibit the Koebner phenomenon. - The skin manifestations in leprosy are primarily due to the infection with *Mycobacterium leprae* rather than an isomorphic response to trauma. *Acne Vulgaris* - Acne vulgaris is a common inflammatory skin condition involving hair follicles and sebaceous glands, characterized by **comedones, papules, pustules, and cysts**. - It is not associated with the Koebner phenomenon; new lesions arise from follicular blockage and inflammation, not from skin trauma in the same manner as psoriasis.

Question 6: Consider the following regarding the human hair growth cycle : I. Anagen is a phase of active hair growth II. Telogen is a transitional phase III. Catagen is a resting phase Which of the statements given above is/are correct?

A. III only
B. I, II and III
C. I only (Correct Answer)
D. I and II only

Explanation: ***I only*** - Statement I is **correct**: **Anagen is the active growth phase** of the hair cycle where hair follicle cells in the matrix rapidly divide and differentiate - The hair shaft actively grows during this phase, which typically lasts **2-7 years** and determines the maximum length of hair - **Only statement I is accurate**, making this the correct answer *III only* - This option is incorrect because statement III claims **Catagen is a resting phase**, which is medically inaccurate - **Catagen is actually the transitional/regression phase** (lasting 2-3 weeks) where hair growth stops and the follicle shrinks - The **resting phase is Telogen**, not Catagen *I, II and III* - This option is incorrect because **both statements II and III contain errors** - Statement II incorrectly identifies **Telogen as a transitional phase** when it is actually the **resting phase** (2-4 months) - Statement III incorrectly identifies **Catagen as a resting phase** when it is actually the **transitional phase** - Only statement I is correct *I and II only* - This option is incorrect because **statement II is inaccurate** - Statement II claims **Telogen is a transitional phase**, but Telogen is actually the **resting phase** where the hair remains in the follicle before shedding - The **transitional phase is Catagen**, not Telogen - Only statement I is correct, not both I and II