Drugs Used in Skin Disorders — MCQs

Drugs Used in Skin Disorders Indian Medical PG Practice Questions and MCQs

Question 31: Which of the following topical steroids is the most potent?

A. Hydrocortisone
B. Halobetasol propionate (Correct Answer)
C. Fluticasone
D. Triamcinolone acetonide

Explanation: ***Correct: Halobetasol propionate*** - **Halobetasol propionate** is a **Class I (super-high potency) topical corticosteroid**, indicating it is among the strongest available. - Its high potency is used for severe dermatoses like psoriasis and lichen planus, but requires careful monitoring due to potential side effects like **skin atrophy**, telangiectasia, and hypothalamic-pituitary-adrenal (HPA) axis suppression. - Should be used for short durations and limited to small body surface areas. *Incorrect: Hydrocortisone* - **Hydrocortisone** is a **Class VII (lowest potency)** topical steroid, primarily used for mild inflammatory conditions like mild eczema or diaper dermatitis. - It is significantly less potent than halobetasol propionate and is often available in over-the-counter preparations. - Safest option for use on face, intertriginous areas, and in children. *Incorrect: Fluticasone* - **Fluticasone propionate** is typically a **medium-potency (Class IV-V)** topical corticosteroid, depending on the formulation and vehicle. - It is commonly used for moderate inflammatory skin conditions like atopic dermatitis, but is not as strong as Class I agents. *Incorrect: Triamcinolone acetonide* - **Triamcinolone acetonide** is available in various strengths, typically falling into **medium-to-high potency categories (Class III-IV)**, depending on the vehicle and concentration. - While effective for many conditions like psoriasis and eczema, it is not considered the most potent topical steroid category, which is occupied by agents like halobetasol propionate and clobetasol propionate.

Question 32: Most common side effect of retinoids is

A. Headache
B. Diarrhoea
C. Photosensitivity
D. Mucocutaneous dryness (Correct Answer)

Explanation: ***Mucocutaneous dryness*** - This is the **most common side effect** of retinoids, particularly oral isotretinoin, occurring in nearly all patients - Manifests as **cheilitis** (dry, cracked lips), **xerosis** (dry skin), **dry nasal mucosa**, and **conjunctival dryness** - Direct result of decreased sebaceous gland activity and altered epithelial differentiation - Managed with **emollients and lip balm** *Headache* - Can occur with retinoid use, but less common than mucocutaneous effects - **Severe headaches** with visual changes may indicate **pseudotumor cerebri** (benign intracranial hypertension), a rare but serious complication requiring immediate discontinuation *Diarrhoea* - **Gastrointestinal side effects** are uncommon with systemic retinoids - Not a characteristic adverse effect of this drug class *Photosensitivity* - While retinoids can increase susceptibility to **sunburn**, this is not the most common side effect - Patients should be advised to use **sunscreen** and avoid excessive sun exposure - Less universal than mucocutaneous dryness

Question 33: All of the following are topical steroids EXCEPT ?

A. Fluticasone propionate
B. Prednisolone (Correct Answer)
C. Betamethasone valerate
D. Hydrocortisone valerate

Explanation: ***Prednisolone*** - **Prednisolone** is an **oral/systemic corticosteroid** primarily used for systemic therapy, not as a topical dermatological preparation. - While prednisolone eye drops and ear drops exist, it is NOT a standard topical corticosteroid for skin disorders. - Its high systemic absorption potential makes it unsuitable for dermatological topical applications. *Fluticasone propionate* - **Fluticasone propionate** is a **highly potent synthetic topical corticosteroid** commonly used in dermatology. - Available as creams and ointments for inflammatory skin conditions like eczema, psoriasis, and atopic dermatitis. - Also formulated as nasal spray for allergic rhinitis. *Betamethasone valerate* - **Betamethasone valerate** is a **potent topical corticosteroid** widely used in dermatology. - Available in various formulations (cream, ointment, lotion) for treating inflammatory skin conditions. - Classified as a mid-to-high potency topical steroid, effective for conditions like eczema, psoriasis, and contact dermatitis. *Hydrocortisone valerate* - **Hydrocortisone valerate** is a **moderate-potency topical corticosteroid** derived from hydrocortisone. - Frequently used in dermatological preparations to treat inflammatory skin conditions like dermatitis and eczema. - Safer for prolonged use and application on sensitive areas compared to more potent steroids.

Question 34: Which of the following drugs are used topically for dermatophytes?

A. Terbinafine
B. Cyclopirox olamine
C. Econazole
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - **Terbinafine**, **Ciclopirox olamine**, and **Econazole** are all commonly used as topical antifungal agents for the treatment of dermatophyte infections. - These drugs target different aspects of fungal cell metabolism or structure to inhibit growth or kill the fungus. *Terbinafine* - It is an **allylamine antifungal** that inhibits **squalene epoxidase**, an enzyme involved in fungal ergosterol synthesis. - While effective topically, terbinafine can also be used orally for more extensive or recalcitrant infections, but the question specifically asks for topical use. *Cyclopirox olamine* - This is a **hydroxypyridone antifungal** that acts by chelating polyvalent metal cations, inhibiting essential enzymes in fungal cells. - It is often used for topical treatment of dermatophyte infections, including **tinea pedis** and **tinea corporis**, and is also used for onychomycosis. *Econazole* - It is an **imidazole antifungal** that inhibits the fungal cytochrome P450 enzyme 14α-demethylase, which is crucial for **ergosterol biosynthesis**. - Commonly available as a cream or solution, econazole is effective against a broad spectrum of fungi, including dermatophytes, and is used for various superficial fungal infections.

Question 35: Contraindicated in Androgenic Alopecia –

A. Minoxidil
B. Testosterone (Correct Answer)
C. Cyproterone
D. Finasteride

Explanation: ***Testosterone*** - Androgenic alopecia, or **male-pattern baldness**, is driven by **androgens**, particularly **dihydrotestosterone (DHT)**, which is derived from testosterone. - Administering exogenous **testosterone** would exacerbate hair loss in individuals with androgenic alopecia by increasing the substrate available for conversion to DHT. *Minoxidil* - **Minoxidil** is a vasodilator that is commonly used topically to treat androgenic alopecia. - It works by **prolonging the anagen phase** of hair growth and increasing follicular size, making it a treatment option, not a contraindication. *Cyproterone* - **Cyproterone** is an **anti-androgen** that blocks androgen receptors and inhibits androgen synthesis. - It is used in some cases of severe androgenic alopecia in women, making it a treatment, not a contraindication. *Finasteride* - **Finasteride** is a **5-alpha-reductase inhibitor** that blocks the conversion of testosterone to dihydrotestosterone (DHT). - By reducing DHT levels, it slows or reverses hair loss in androgenic alopecia, making it a common treatment and not a contraindication.

Question 36: FTU is a measure of:

A. Mucosal involvement in pemphigus
B. Amount of topical drug to be applied (Correct Answer)
C. Area involved in severe drug reactions
D. Concentration of drug in topical preparations

Explanation: ***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.

Question 37: All these drugs are known to exacerbate psoriasis, except:

A. Beta blocker
B. Hydroxychloroquine
C. Ciclosporin (Correct Answer)
D. Lithium

Explanation: ***Ciclosporin*** - **Ciclosporin** is an immunosuppressant often used to **treat severe psoriasis**, not exacerbate it. - It works by inhibiting the activation of T-cells, which are central to the pathogenesis of psoriasis. *Beta blocker* - **Beta-blockers**, particularly non-selective ones like **propranolol**, can worsen existing psoriasis or induce new lesions. - The mechanism is thought to involve effects on beta-adrenergic receptors in the skin, leading to inflammation. *Hydroxychloroquine* - **Hydroxychloroquine**, an antimalarial and immunosuppressant, can trigger or exacerbate psoriasis, especially **pustular psoriasis**. - It likely affects keratinocyte proliferation and immune responses in the skin. *Lithium* - **Lithium** is a mood stabilizer that is known to exacerbate or trigger various forms of psoriasis, including **plaque psoriasis** and **pustular psoriasis**. - The mechanism is believed to involve alterations in cyclic AMP metabolism and arachidonic acid pathways within keratinocytes.

Question 38: Dapsone is NOT used in:

A. Dermatitis herpetiformis
B. Alopecia areata (Correct Answer)
C. Pneumocystis jirovecii pneumonia prophylaxis
D. Leprosy

Explanation: ***Alopecia areata*** - **Dapsone** is an **antibiotic** with anti-inflammatory and immunomodulatory properties and is not indicated for the treatment of **alopecia areata**. - Treatment for **alopecia areata** typically involves **corticosteroids** (topical, intralesional, or systemic) or other immunosuppressants. *Dermatitis herpetiformis* - **Dapsone** is the **first-line treatment** for **dermatitis herpetiformis** due to its rapid antipruritic effect, often providing relief within 24-48 hours. - It works by reducing the inflammation and formation of the characteristic **subepidermal blisters** seen in this condition. *Pneumocystis jirovecii pneumonia prophylaxis* - **Dapsone** is an effective **alternative agent** for prophylaxis against **Pneumocystis jirovecii pneumonia (PCP)**, especially in patients who cannot tolerate trimethoprim-sulfamethoxazole. - It is often used in combination with **pyrimethamine** for toxoplasmosis prophylaxis in HIV-infected patients. *Leprosy* - **Dapsone** is a crucial component of **multidrug therapy (MDT)** for both paucibacillary and multibacillary forms of **leprosy**. - It acts as a **bacteriostatic agent** against Mycobacterium leprae and has been a cornerstone of leprosy treatment for decades.

Question 39: Imiquimod is administered by which route?

A. Topical (Correct Answer)
B. Inhalation
C. Intranasal
D. Oral

Explanation: ***Topical*** - **Imiquimod** is a topical immune response modifier that is applied directly to the skin as a cream (typically 5% concentration). - It is commonly used for the treatment of **external genital and perianal warts**, superficial basal cell carcinoma, and actinic keratosis. - Works by stimulating local immune response through **toll-like receptor 7 (TLR7) activation**. *Inhalation* - **Imiquimod** is not formulated for inhalation and is not effective when administered via the respiratory tract. - It is specifically designed as a dermatological preparation for **direct skin application** only. *Intranasal* - **Imiquimod** is not designed for intranasal administration and would not achieve therapeutic concentrations at target sites this way. - Intranasal application could lead to **mucosal irritation** and lack of efficacy for its primary dermatological indications. *Oral* - **Imiquimod** is not available in oral formulation and would not be effective systemically. - Its mechanism requires **local application** to activate skin-resident immune cells at the site of pathology.

Question 40: Scabies oral treatment of choice:

A. Benzyl Benzoate
B. Ivermectin (Correct Answer)
C. Lindane
D. Permethrin

Explanation: ***Ivermectin*** - **Ivermectin** is the **oral treatment of choice** for scabies, especially in cases of crusted (Norwegian) scabies, immunocompromised patients, or when topical treatments fail. - It works by disrupting the **neurotransmitter system** of parasites, leading to paralysis and death of the scabies mites. *Benzyl Benzoate* - **Benzyl benzoate** is a **topical scabicide** and acaricide, used as a lotion or emulsion. - It is not available as an oral formulation and is typically reserved for cases where other topical agents are ineffective or contraindicated. *Lindane* - **Lindane** (gamma-hexachlorocyclohexane) is a topical scabicide but is **not recommended as a first-line treatment** due to potential **neurotoxicity** (seizures) especially in infants, children, and individuals with extensive skin excoriations. - It is used topically and has significant systemic absorption, making its use limited. *Permethrin* - **Permethrin** cream is considered the **first-line topical treatment** for scabies, showing high efficacy and a good safety profile. - It is not an oral medication; it is applied topically to the skin to kill mites.

Practice by Chapter

Topical Corticosteroids

Practice Questions

Topical Antimicrobials

Practice Questions

Antiacne Medications

Practice Questions

Drugs for Psoriasis

Practice Questions

Antihistamines in Dermatological Conditions

Practice Questions

Sunscreens and Photoprotective Agents

Practice Questions

Agents for Pigmentary Disorders

Practice Questions

Drugs for Parasitic Skin Infestations

Practice Questions

Keratolytics and Emollients

Practice Questions

Biological Agents in Dermatology

Practice Questions

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