Dermatological Pharmacology Practice Questions

Q: A 20-year-old patient with focal seizures was prescribed Carbamazepine. Four weeks later he presents with fever and multiple skin lesions with periorbital edema. On examination generalized lymph nodes enlargement is noted. Blood work shows marked eosinophilia with atypical lymphocytosis. What is the diagnosis?

DRESS syndrome. ***DRESS syndrome*** - The combination of **fever**, widespread **skin lesions**, **periorbital edema**, **generalized lymphadenopathy**, **eosinophilia**, and atypical lymphocytosis following **carbamazepine** use is highly characteristic of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome. - DRESS syndrome typically has a **delayed onset** (2-8 weeks) after drug initiation and involves multiple organ systems, which aligns with the patient's presentation. *TEN/SJS* - While both Toxic Epidermal Necrolysis (TEN) and Stevens-Johnson Syndrome (SJS) are severe cutaneous adverse reactions to drugs, they are primarily characterized by **epidermal detachment** and severe mucosal involvement, which are not explicitly described here. - Although these can present with fever and skin lesions, they typically do not involve prominent **lymphadenopathy** or **marked eosinophilia** to the extent seen in this case. *Fixed drug eruption* - A fixed drug eruption is characterized by **recurrent skin lesions** that appear in the **same location** each time a particular drug is administered. - It does not typically involve systemic symptoms such as **fever**, **lymphadenopathy**, or significant **eosinophilia**. *Hypereosinophilic syndrome* - This syndrome is a persistent, unexplained **eosinophilia** (typically >1500 cells/µL) that lasts for at least 6 months and is associated with signs and symptoms of **organ dysfunction** due to eosinophil infiltration. - While this patient has eosinophilia, the clear association with a drug (carbamazepine), the presence of widespread skin lesions, fever, and lymphadenopathy point more towards a drug-induced hypersensitivity reaction like DRESS syndrome rather than primary hypereosinophilic syndrome.

Q: A 30-year-old Han Chinese woman with multiple episodes of GTCS was prescribed phenytoin by district hospital physician. After 7 days she presents with fever, malaise, mucosal erosions involving the oral and conjunctival mucosa, and widespread skin involvement with epidermal detachment. Which of the following will predispose to the condition shown here? (Recent NEET Pattern 2016-17)

HLA B1502. ***HLA-B*1502*** - The image shows a **severe cutaneous adverse reaction (SCAR)** to phenytoin, representing **Stevens-Johnson Syndrome (SJS)/Toxic Epidermal Necrolysis (TEN)** with widespread epidermal necrosis, detachment, and mucosal involvement. - The **HLA-B*1502** allele is strongly associated with an increased risk of **phenytoin-induced SJS/TEN** in patients of **Asian descent** (particularly Han Chinese, Thai, and South Asian populations). - This genetic marker has been identified as a major predisposing factor for aromatic antiepileptic drug-induced severe cutaneous reactions, including those from **phenytoin, carbamazepine, and oxcarbazepine**. - Screening for HLA-B*1502 is recommended before initiating these drugs in high-risk populations. *HLA-B*5801* - The **HLA-B*5801** allele is strongly associated with **allopurinol-induced severe cutaneous adverse reactions**, including SJS and TEN. - However, this patient was prescribed **phenytoin, not allopurinol**, and HLA-B*5801 is not the primary genetic marker for phenytoin-induced reactions. *HLA-DQ2, DR3, DR4* - **HLA-DQ2 and DR3/DR4** are genetic markers primarily associated with **celiac disease** and autoimmune disorders like **Type 1 Diabetes Mellitus**. - These HLA alleles are not associated with drug-induced severe cutaneous adverse reactions or phenytoin hypersensitivity. *HLA-DR4* - **HLA-DR4** is associated with autoimmune diseases, most notably **rheumatoid arthritis**, **Type 1 Diabetes**, and **pemphigus vulgaris**. - There is no established association between HLA-DR4 and phenytoin-induced severe cutaneous adverse reactions or SJS/TEN.

Q: A patient presented with fever and joint pain for which she was put on NSAIDs. After 10 days she developed a skin lesion as shown in the image. The lesion is bilateral, symmetrical, and centrofacially distributed over the nose and malar regions, without any preceding dusky erythematous plaque and not confined to a single sharply demarcated site. Diagnosis is:

Chikungunya. ***Chikungunya*** - The image demonstrates **centrofacial/nasal hyperpigmentation**, a characteristic finding known as the **"Chik sign"**, which is a post-febrile cutaneous manifestation associated with chikungunya infection. - The **Chik sign** refers to a distinctive **centrofacial or nasal hyperpigmentation** that can develop following chikungunya fever, typically appearing days to weeks after the acute febrile illness. - The clinical history of **fever and severe joint pain (arthralgia)** is classic for chikungunya, and the subsequent development of nasal/centrofacial hyperpigmentation is consistent with this diagnosis. - The pigmentation in chikungunya-associated skin changes tends to be **bilateral, symmetrical, and centrofacially distributed**, particularly over the nose and malar regions, as seen in the image. *Fixed drug eruption* - Fixed drug eruptions typically present as **well-demarcated, erythematous, and pigmented patches** that recur at the **same site(s)** upon re-exposure to the offending drug. - While NSAIDs are known culprits for FDE, the **centrofacial nasal distribution** and the clinical context of fever with arthralgia are more consistent with chikungunya-associated hyperpigmentation than a fixed drug eruption. *Dengue* - Dengue fever presents with **fever, joint pain, and often a rash**, but the rash is usually a generalized **macular or maculopapular eruption**, sometimes with petechiae, and is not typically a centrofacial nasal hyperpigmentation pattern. - Similar to Chikungunya, the timing and morphology of the lesion are not typical for Dengue rash. *Melasma* - Melasma is a chronic skin condition causing **dark, discolored patches** on the face, primarily due to hormonal changes (e.g., pregnancy, birth control) or sun exposure. - It does not typically present acutely after a febrile illness with accompanying arthralgia.

Q: FTU is a measure of:

Amount of topical drug to be applied. ***Amount of topical drug to be applied*** - A **finger-tip unit (FTU)** is a standardized measure representing the amount of topical medication needed to cover a specific body area, typically about **0.5 grams**. - It ensures appropriate dosing, as one FTU is generally sufficient to treat an area equivalent to the size of an adult hand (palm and fingers). *Mucosal involvement in pemphigus* - **FTU** is a measure for **topical drug application**, not for assessing the extent of mucosal lesions in autoimmune bullous diseases like pemphigus. - The severity of pemphigus, including mucosal involvement, is assessed by clinical examination and specific scoring systems. *Area involved in severe drug reactions* - The **FTU** is not used to quantify the body surface area affected in severe drug reactions. - Conditions like **Stevens-Johnson Syndrome (SJS)** or **Toxic Epidermal Necrolysis (TEN)** use specific scoring systems and percentages of body surface area for assessment. *Concentration of drug in topical preparations* - **FTU** refers to the **volume or weight** of a topical product, not the concentration of the active drug within the preparation. - The drug concentration is typically expressed as a percentage or mg/g and is listed on the product packaging.

Q: Steroids are used in the Rx of the following diseases EXCEPT:

Chronic fungal infection. ***Chronic fungal infection*** - **Steroids are absolutely contraindicated** in **chronic fungal infections** as they **suppress cell-mediated immunity**, leading to worsening of the infection and potential dissemination. - Corticosteroids promote fungal growth and can convert a localized infection into a systemic, life-threatening condition. - This is the **clearest contraindication** among the options. *Pemphigus vulgaris* - **Pemphigus vulgaris** is an **autoimmune blistering disease** where **high-dose systemic steroids are the first-line treatment**. - Corticosteroids (1-2 mg/kg/day of prednisolone) are essential for controlling autoantibody production and preventing life-threatening complications. - **Steroids are clearly indicated**, not contraindicated. *Erythema multiforme* - **Erythema multiforme** is typically a **self-limiting condition** managed primarily with **supportive care** (antipyretics, antihistamines, topical care). - **Systemic steroids are generally NOT recommended** as standard treatment and their use remains **controversial**. - However, in very rare severe cases with extensive mucosal involvement, some clinicians may consider a short course, making this **not an absolute contraindication** like fungal infections. *Contact dermatitis* - **Contact dermatitis** is commonly treated with **topical corticosteroids** as first-line therapy to reduce inflammation and pruritus. - In severe, widespread cases, a short course of **oral steroids** may be prescribed. - **Steroids are clearly indicated** for this condition.

Q: A 35 years old female presented with acne. She was treated for her acne but after the treatment, she developed pigmentation. Which drug is responsible for hyperpigmentation?

Minocycline. ***Minocycline*** - **Minocycline** is known to cause different types of hyperpigmentation, including blue-grey discoloration of the skin, scars, mucosa, eyes, and teeth, especially with long-term use. - This pigmentation can be due to the accumulation of **iron oxide** and **minocycline degradation products** in tissues. *Doxycycline (a tetracycline antibiotic)* - While doxycycline is a tetracycline, it is **less commonly associated with significant hyperpigmentation** compared to minocycline. - It can cause photosensitivity, which might lead to hyperpigmentation in sun-exposed areas, but direct drug-induced blue-grey discoloration is rare. *Tetracycline (a tetracycline antibiotic)* - **Tetracycline** can cause tooth discoloration, especially in children, and photosensitivity, but direct drug-induced skin hyperpigmentation as described is **less common** than with minocycline. - Other side effects like gastrointestinal upset are more prominent. *Erythromycin (a macrolide antibiotic)* - **Erythromycin** is a macrolide antibiotic and is **not typically associated with significant skin hyperpigmentation** as a side effect. - Common side effects include gastrointestinal disturbances like nausea, vomiting, and diarrhea.

Q: Match the systemic medications with their most characteristic cutaneous adverse effects: 1. Hydroxyurea a. Acral erythema 2. Capecitabine b. Leg ulcers 3. EGFR inhibitors c. Acneiform eruption

1-b, 2-a, 3-c. ***1-b, 2-a, 3-c*** - **Hydroxyurea** is well-known to cause **leg ulcers**, particularly in patients with myeloproliferative disorders. These ulcers are often chronic and difficult to heal. - **Capecitabine** is a prodrug of 5-fluorouracil and characteristically causes **acral erythema**, also known as hand-foot syndrome, presenting as redness, swelling, and pain on the palms and soles. - **EGFR inhibitors** frequently lead to an **acneiform eruption**, often described as a papulopustular rash resembling acne, which can involve the face, scalp, and trunk. *1-a, 2-b, 3-c* - This option incorrectly associates Hydroxyurea with acral erythema; **acral erythema (hand-foot syndrome)** is a classic side effect of **capecitabine**, not hydroxyurea. - It also incorrectly associates capecitabine with leg ulcers; **leg ulcers** are a known adverse effect of **hydroxyurea**, not capecitabine. *1-c, 2-a, 3-b* - This option incorrectly links Hydroxyurea with acneiform eruption; **acneiform eruption** is characteristic of **EGFR inhibitors**. - It also incorrectly attributes leg ulcers to EGFR inhibitors; **leg ulcers** are a common side effect of **hydroxyurea**. *1-b, 2-c, 3-a* - This option incorrectly attributes acneiform eruption to capecitabine; **acneiform eruption** is specifically linked to **EGFR inhibitors**. - It also incorrectly associates EGFR inhibitors with acral erythema; **acral erythema** is a characteristic side effect of **capecitabine**.

Q: Which mechanism best explains the therapeutic effect of coal tar in psoriasis?

Anti-inflammatory. ***Anti-inflammatory*** - Coal tar exerts significant **anti-inflammatory effects**, reducing erythema, scaling, and pruritus in psoriatic plaques. - It also has important **antiproliferative effects** on keratinocytes, normalizing the accelerated epidermal turnover characteristic of psoriasis. - Both anti-inflammatory and antiproliferative mechanisms contribute to its therapeutic efficacy. - The exact molecular mechanisms remain incompletely understood but likely involve effects on cytokine production and cell signaling pathways. *DNA synthesis inhibition* - While coal tar does have **antiproliferative properties** that reduce keratinocyte proliferation, this is considered part of its overall mechanism rather than the singular best explanation. - The question asks for the mechanism that "best explains" the effect, and anti-inflammatory action is more broadly recognized as the primary characterization. - Other agents like **methotrexate** work more specifically through direct DNA synthesis inhibition. *Immunosuppression* - Coal tar is **not a systemic immunosuppressant** like cyclosporine or biologics (anti-TNF agents, IL-17 inhibitors). - Its effects are primarily local and topical, targeting skin inflammation rather than systemic immune modulation. - It does not suppress T-cell function or other immune pathways to the degree of true immunosuppressive agents. *Keratolysis* - Coal tar has **mild keratolytic properties** (helps remove scales), but this is a secondary benefit rather than its primary therapeutic mechanism. - **Salicylic acid** is the prototypical keratolytic agent and is often combined with coal tar in psoriasis treatment. - The descaling effect aids in allowing the active anti-inflammatory and antiproliferative components to penetrate better.

Q: A 50-year-old woman presents with a well-defined erythematous patch on her leg following the administration of an antibiotic. What is the most likely diagnosis?

Fixed drug eruption. ***Fixed drug eruption*** - This condition presents as a **solitary, well-demarcated erythematous patch** that recurs at the **same cutaneous site** upon re-exposure to an offending drug. - The history of antibiotic administration followed by a localized patch is highly characteristic of a **fixed drug eruption**. *Contact dermatitis* - This typically results from direct skin exposure to an allergen or irritant, causing an **itchy rash** that is usually not well-demarcated and may include vesicles or bullae. - It would not typically be related to systemic drug administration and does not recur at the same site with repeated systemic exposure. *Psoriasis* - Characterized by **silvery scales** on well-demarcated **erythematous plaques**, often on extensor surfaces like elbows and knees. - It is a chronic inflammatory condition and does not typically present as a single, acute lesion in response to medication. *Tinea corporis* - This is a **fungal infection** of the skin, presenting as a **ring-shaped lesion** with central clearing and raised, scaly borders. - It is not caused by drug administration and has specific morphological features (e.g., scaling, annular pattern) that differentiate it from the described lesion.

Question 1

A 20-year-old patient with focal seizures was prescribed Carbamazepine. Four weeks later he presents with fever and multiple skin lesions with periorbital edema. On examination generalized lymph nodes enlargement is noted. Blood work shows marked eosinophilia with atypical lymphocytosis. What is the diagnosis?

Accepted Answer

DRESS syndrome

Answer

TEN/SJS

Answer

Fixed drug eruption

Answer

Hypereosinophilic syndrome

Question 2

A 30-year-old Han Chinese woman with multiple episodes of GTCS was prescribed phenytoin by district hospital physician. After 7 days she presents with fever, malaise, mucosal erosions involving the oral and conjunctival mucosa, and widespread skin involvement with epidermal detachment. Which of the following will predispose to the condition shown here? (Recent NEET Pattern 2016-17)

Accepted Answer

HLA B1502

Answer

HLA B5801

Answer

HLA DQ2 DR3 DR4

Answer

HLA DR4

Question 3

A patient presented with fever and joint pain for which she was put on NSAIDs. After 10 days she developed a skin lesion as shown in the image. The lesion is bilateral, symmetrical, and centrofacially distributed over the nose and malar regions, without any preceding dusky erythematous plaque and not confined to a single sharply demarcated site. Diagnosis is:

Accepted Answer

Chikungunya

Answer

Melasma

Answer

Fixed drug eruption

Answer

Dengue

Question 4

A 30-year-old male presents with joint pain and NSAIDs were prescribed. After one week, joint pain is persisting and he has developed brownish discoloration over nose as shown in the figure. The nasal discoloration was not preceded by any localized erythematous or inflamed lesion, and there is no prior history of a similar lesion at the same site. This was due to: (AIIMS Nov 2017)

Accepted Answer

Chikungunya

Answer

Melasma

Answer

Fixed drug eruption

Answer

Dengue

Question 5

FTU is a measure of:

Accepted Answer

Amount of topical drug to be applied

Answer

Mucosal involvement in pemphigus

Answer

Area involved in severe drug reactions

Answer

Concentration of drug in topical preparations

Question 6

Steroids are used in the Rx of the following diseases EXCEPT:

Accepted Answer

Chronic fungal infection

Answer

Pemphigus vulgaris

Answer

Erythema multiforme

Answer

Contact dermatitis

Question 7

A 35 years old female presented with acne. She was treated for her acne but after the treatment, she developed pigmentation. Which drug is responsible for hyperpigmentation?

Accepted Answer

Minocycline

Answer

Doxycycline

Answer

Tetracycline

Answer

Erythromycin

Question 8

Match the systemic medications with their most characteristic cutaneous adverse effects:
1. Hydroxyurea a. Acral erythema
2. Capecitabine b. Leg ulcers
3. EGFR inhibitors c. Acneiform eruption

Accepted Answer

1-b, 2-a, 3-c

Answer

1-a, 2-b, 3-c

Answer

1-c, 2-a, 3-b

Answer

1-b, 2-c, 3-a

Question 9

Which mechanism best explains the therapeutic effect of coal tar in psoriasis?

Accepted Answer

Anti-inflammatory

Answer

DNA synthesis inhibition

Answer

Immunosuppression

Answer

Keratolysis

Question 10

A 50-year-old woman presents with a well-defined erythematous patch on her leg following the administration of an antibiotic. What is the most likely diagnosis?

Accepted Answer

Fixed drug eruption

Answer

Contact dermatitis

Answer

Psoriasis

Answer

Tinea corporis

Dermatological Pharmacology — MCQs

Dermatological Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?