Drugs Used in Skin Disorders Practice Questions

Q: Dapsone is NOT used in:

Alopecia areata. ***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.

Q: Ovicidal drug for scabies is:

Permethrin. ***Permethrin*** - **Permethrin** is the recommended first-line treatment for scabies due to its high efficacy as both a **scabicide** and an **ovicidal agent**, meaning it kills both mites and their eggs. - It works by disrupting the **sodium channel system** causing neurotoxicity in parasitic insects resulting in paralysis and death of the mites. - Applied as 5% cream, it is safe and effective for all age groups including infants. *Ivermectin* - **Ivermectin** is an effective oral alternative for scabies treatment, particularly useful in **crusted scabies** or treatment failures. - However, it has **limited ovicidal activity** and primarily kills adult mites, often requiring a second dose after 1-2 weeks. - Not recommended as first-line for typical scabies when ovicidal activity is desired. *DDT* - **DDT (dichlorodiphenyltrichloroethane)** is an organochlorine insecticide primarily known for its use against mosquitoes and agricultural pests, but it is **not used for treating scabies** in humans. - Its use has been largely restricted due to its **environmental persistence** and potential health risks. *BHC (Lindane)* - **Benzene hexachloride (BHC)**, also known as **lindane**, is an older scabicide that has fallen out of favor due to concerns about **neurotoxicity**, particularly in children and individuals with compromised skin barriers. - While it has some ovicidal properties, its **safety profile** is less favorable compared to permethrin and is no longer recommended as first-line therapy.

Q: Imiquimod is administered by which route?

Topical. ***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.

Q: Permethrin is used in the topical treatment of:

Scabies. ***Scabies*** - **Permethrin** cream, typically 5%, is the **first-line treatment for scabies**, an infestation caused by the mite *Sarcoptes scabiei* [1], [2]. - It works by **neurotoxic action** on the mite, leading to paralysis and death [1]. - Applied from neck down, left on for 8-14 hours, then washed off [2]. *Psoriasis* - Psoriasis is a chronic **autoimmune skin condition** characterized by rapid skin cell turnover, forming scaly plaques [5]. - Treatment involves **corticosteroids, vitamin D analogs, retinoids, or biologics**; permethrin is not indicated [4]. - Permethrin has no anti-inflammatory or immunomodulatory properties. *Acne* - Acne is a multifactorial condition involving **sebaceous glands and hair follicles**, leading to comedones and inflammatory lesions. - Treatment typically includes **topical retinoids, benzoyl peroxide, antibiotics**, or oral medications; permethrin has no role [4]. - Permethrin does not affect sebum production or *Cutibacterium acnes*. *Tinea* - Tinea refers to **fungal infections** of the skin, hair, or nails (ringworm, athlete's foot) [3]. - These infections require **topical or oral antifungal agents** (e.g., azoles, terbinafine), not permethrin [3]. - Permethrin is an insecticide with no antifungal activity.

Q: All of the following are true about "Imiquimod" except:

Direct antiviral activity. ***Direct antiviral activity*** - Imiquimod is a **Toll-like receptor 7 (TLR7) agonist** that primarily works by **stimulating the immune system** to produce cytokines, which then fight viral infections and cancerous cells. - It does not directly inhibit viral replication or destroy viral particles; its action is entirely **immune-mediated**. *Antitumor activity* - Imiquimod stimulates the local immune response, leading to the production of interferons and other cytokines that can inhibit the growth of **tumor cells**, such as in basal cell carcinoma. - This activity is **indirect**, as it relies on the host immune system rather than direct cytotoxic effects on cancer cells. *Indirect antiviral activity* - As a TLR7 agonist, imiquimod prompts immune cells to release significant amounts of **cytokines** like interferon-alpha, which have potent antiviral effects. - This **enhances the body's natural defense mechanisms** against viral infections, such as those causing genital warts. *It releases cytokines* - Imiquimod's mechanism of action involves binding to **Toll-like receptor 7 (TLR7)** on immune cells like macrophages and dendritic cells. - This binding triggers a signaling cascade that results in the robust production and release of various **pro-inflammatory and anti-viral cytokines**, including interferons and TNF-alpha.

Q: Podophyllum resin is indicated in the treatment of:

Condyloma acuminata.. ***Condyloma acuminata.*** - **Podophyllum resin** is a cytotoxic agent that inhibits cell division and is commonly used as a topical treatment for **genital warts (condyloma acuminata)**. - Its mechanism involves arresting cells in metaphase by interfering with microtubule assembly, leading to necrosis of the wart tissue. *Pemphigus.* - **Pemphigus** is an autoimmune blistering disease of the skin and mucous membranes, not treated with podophyllum resin. - Treatment typically involves **systemic corticosteroids** and other immunosuppressive agents. *Psoriasis.* - **Psoriasis** is a chronic inflammatory skin condition characterized by accelerated epidermal cell turnover, and **podophyllum resin is not indicated for its treatment**. - Management often includes topical corticosteroids, vitamin D analogs, phototherapy, and systemic immunomodulators. *Condylomata lata.* - **Condylomata lata** are broad, flat, moist lesions characteristic of **secondary syphilis**, and they are highly infectious. - Treatment involves **penicillin** for syphilis, as condylomata lata are a manifestation of the underlying spirochete infection.

Q: Imiquimod is used in the treatment of -

Anogenital warts. ***Anogenital warts*** - **Imiquimod** is a topical immune response modifier primarily used for treating **external anogenital warts** caused by Human Papillomavirus (HPV). - It works by stimulating the immune system to produce **interferon-alpha** and other cytokines, which fight the viral infection. *Tinea versicolor* - **Tinea versicolor** is a superficial fungal infection caused by **Malassezia species**. - It is typically treated with **topical antifungal agents** (e.g., ketoconazole, selenium sulfide) or oral antifungals in widespread cases. *Melanoma* - **Melanoma** is a serious form of skin cancer that requires treatment with **surgical excision**, chemotherapy, radiation, or targeted therapies/immunotherapy. - **Imiquimod** is not a standard treatment for melanoma, although it has been investigated in some superficial or early forms, its use is limited to **superficial basal cell carcinoma** and **actinic keratosis**. *Sezary syndrome* - **Sézary syndrome** is an advanced and aggressive form of **cutaneous T-cell lymphoma (CTCL)**, characterized by erythroderma, lymphadenopathy, and circulating malignant T-cells. - Treatment involves systemic therapies such as **chemotherapy**, photopheresis, radiation, and biological agents. Imiquimod has no role in its management.

Q: Which of the following drugs is NOT used in scabies?

Ciclopirox oleamine. ***Ciclopirox oleamine*** - **Ciclopirox oleamine** is an **antifungal** medication used to treat various fungal skin infections, such as tinea infections and candidiasis. - It has no known activity against the **Sarcoptes scabiei mite**, which causes scabies. *Benzene hexachloride* - **Benzene hexachloride**, specifically **lindane**, is an **organochloride insecticide** that has been used topically to treat scabies. - Its use has become more limited due to concerns about neurotoxicity, particularly in infants and individuals with seizures. *Permethrin* - **Permethrin** cream (5%) is a **pyrethroid insecticide** and is considered a **first-line treatment** for scabies due to its high efficacy and low toxicity. - It works by disrupting the nervous system of the mite, leading to paralysis and death. *Crotamiton* - **Crotamiton** is an **antipruritic** and **scabicidal** agent that is used to treat scabies, as well as to relieve itching. - It is less effective than permethrin for scabies but can be an alternative, especially when permethrin is contraindicated or not tolerated.

Q: Which drug can be given as a nail lacquer treatment in onychomycosis?

Ciclopirox olamine (nail lacquer). ***Ciclopirox olamine (nail lacquer)*** - **Ciclopirox olamine** is an antifungal agent formulated as a nail lacquer, specifically designed for topical application in **onychomycosis**. - Its mechanism involves interfering with fungal cellular processes, transported directly to the nail bed where the fungal infection resides. *Terbinafine* - **Terbinafine** is primarily an **oral antifungal** medication or available as a topical cream, but not typically in a nail lacquer formulation for onychomycosis. - While highly effective against dermatophytes causing onychomycosis, its systemic absorption is key to its efficacy when administered orally. *Nystatin* - **Nystatin** is an antifungal agent primarily effective against **Candida** species and is not typically used for dermatophyte-induced onychomycosis, nor is it commonly formulated as a nail lacquer. - Its broad spectrum is limited in this context, as most onychomycosis cases are caused by dermatophytes, which are less susceptible to nystatin. *Itraconazole* - **Itraconazole** is a **systemic antifungal** medication, effective in treating onychomycosis, but it is not available as a nail lacquer. - It works by inhibiting fungal cytochrome P450 enzymes, which are critical for ergosterol synthesis, a component of the fungal cell membrane.

Q: What is the mechanism of vitamin D analogues in psoriasis?

Keratinocyte differentiation. ***Keratinocyte differentiation*** - Vitamin D analogues bind to the **vitamin D receptor (VDR)** in keratinocytes, promoting their **differentiation** and inhibiting their abnormal proliferation. - This action helps to normalize the growth and maturation of skin cells, which are excessively produced in psoriasis. *T cell suppression* - While **T-cell activity** plays a crucial role in psoriasis pathogenesis, vitamin D analogues primarily target keratinocyte function rather than directly suppressing T cells. - Other treatments like **corticosteroids** or **biologics** are more directly involved in immune suppression. *Antimicrobial action* - Vitamin D itself has some **immunomodulatory effects** and can influence antimicrobial peptides, but this is not the primary mechanism of its analogues in treating psoriasis. - The direct and significant impact is on **keratinocyte behavior**. *Antipruritic effect* - Relieving **pruritus (itching)** can be a secondary benefit of resolving psoriatic lesions, but vitamin D analogues do not have a direct **antipruritic mechanism**. - Their primary action is to address the underlying **pathophysiology** of the disease.

Question 1

Dapsone is NOT used in:

Accepted Answer

Alopecia areata

Answer

Dermatitis herpetiformis

Answer

Pneumocystis jirovecii pneumonia prophylaxis

Answer

Leprosy

Question 2

Ovicidal drug for scabies is:

Accepted Answer

Permethrin

Answer

DDT

Answer

BHC

Answer

Ivermectin

Question 3

Imiquimod is administered by which route?

Accepted Answer

Topical

Answer

Inhalation

Answer

Intranasal

Answer

Oral

Question 4

Permethrin is used in the topical treatment of:

Accepted Answer

Scabies

Answer

Psoriasis

Answer

Acne

Answer

Tinea

Question 5

All of the following are true about "Imiquimod" except:

Accepted Answer

Direct antiviral activity

Answer

Antitumor activity

Answer

Indirect antiviral activity

Answer

It releases cytokines

Question 6

Podophyllum resin is indicated in the treatment of:

Accepted Answer

Condyloma acuminata.

Answer

Pemphigus.

Answer

Psoriasis.

Answer

Condylomata lata.

Question 7

Imiquimod is used in the treatment of -

Accepted Answer

Anogenital warts

Answer

Tinea versicolor

Answer

Melanoma

Answer

Sezary syndrome

Question 8

Which of the following drugs is NOT used in scabies?

Accepted Answer

Ciclopirox oleamine

Answer

Benzene hexachloride

Answer

Permethrin

Answer

Crotamiton

Question 9

Which drug can be given as a nail lacquer treatment in onychomycosis?

Accepted Answer

Ciclopirox olamine (nail lacquer)

Answer

Terbinafine

Answer

Nystatin

Answer

Itraconazole

Question 10

What is the mechanism of vitamin D analogues in psoriasis?

Accepted Answer

Keratinocyte differentiation

Answer

T cell suppression

Answer

Antimicrobial action

Answer

Antipruritic effect

Drugs Used in Skin Disorders — MCQs

Drugs Used in Skin Disorders — MCQs

On this page

Practice by Chapter

Want unlimited practice?