Pharmacology for Dermatology Flashcards

Question

Which systemic therapy is recommended for pruritus in the elderly with neurogenic conditions? A) Montelukast B) Gabapentin and pregabalin C) Sedating antihistamines D) Topical capsaicin

Answer 1

**Answer: B) Gabapentin and pregabalin are recommended for pruritus in elderly patients with neurogenic conditions such as peripheral neuropathy.** Explanation: A) Montelukast are more for chronic urticaria in addition to NON-sedating histamines C) Sedating antihistamines should generally be avoided if possible, especially in the elderly. D) Topical capsaicin is useful for neurogenic pruritus but is not systemic.

Answer 2

**Correct Answer: C) Ointment ✅ C is correct: Ointments are ideal for smooth, non-hairy skin because they are lubricating, semi-occlusive, and provide better absorption. E.g. Petrolatum like - Lubricating, semiocclusive, greasy, does not sting - Useful for smooth, non-hairy skin and for dry, thick, or hyperkeratotic lesions ** ❌ A is incorrect: Lotion is alcohol-based and often stings, making it less suitable for dry skin. - Pourable alcohol-based liquid - Less greasy, less occlusive, often stings - Good for hairy areas ❌ B is incorrect: Gel is alcohol-based and dries quickly, which may cause irritation and is less suitable for dry areas. - Alcohol based so may sting, is least occlusive, dries quickly - Good for acne and on the scalp/hairy areas without matting ❌ D is incorrect: Cream is less greasy but can sting and cause irritation due to preservatives/fragrances. - Vanish when rubbed in -Less greasy, not occlusive - Good for intertriginous areas

Answer 3

**Correct Answer: B) The frequency of routine use. ✅ B is correct: The most predictive factor for the benefit of emollients is frequent and routine use, particularly when applied twice daily (BID) and after bathing.** ❌ A is incorrect: The concentration of the emollient is not as important as the frequency of use for effectiveness. ❌ C is incorrect: Inflammation is addressed by corticosteroids, not emollients. ❌ D is incorrect: While vehicle type affects absorption, the frequency of use is the most critical factor for emollient effectiveness.

Answer 4

**Correct Answer: B) Low-potency steroids are appropriate for use on facial areas and thin skin. ✅ B is correct: Low-potency corticosteroids are the preferred choice for sensitive areas with thinner skin, such as the face and genital areas.** ❌ A is incorrect: Super-high potency steroids are used for severe dermatoses, not mild ones. ❌ C is incorrect: The vehicle does affect corticosteroid potency (e.g., ointments have better absorption than creams). ❌ D is incorrect: Ointments are more effective than creams for treating dry, thick lesions because of better absorption. **CORTICOSTEROIDS** * Low potency steroids can be used on large areas and thinner skin - Face, eyelid, genital, intertriginous areas * The vehicle can change the potency of the corticosteroid * Ointments allow for better absorption - E.g., Mometasone furoate ointment is high potency while the cream is medium potency

Answer 5

**✅ Correct Answer: C) Drug expiration date** Explanation: A corticosteroid prescription requires the generic name, vehicle, concentration, directions (Sig), amount, and refills. The expiration date is not typically included in a prescription but is provided by the manufacturer or pharmacy. **CORTICOSTEROID PRESCRIPTIONS Example** * Generic name * Vehicle * Concentration * Sig (Directions) * Amount * Refills * Mometasone furoate ointment 0.1% apply to affected body areas daily * 15 grams refills 3

Answer 6

**✅ Correct Answer: B) They lack the skin-thinning effects of corticosteroids** Explanation: Calcineurin inhibitors (tacrolimus, pimecrolimus) are often used as first-line therapy for the face and intertriginous areas because they do not cause skin atrophy, which is a common side effect of corticosteroids. Wrong choices: A) Incorrect—They do not necessarily have a faster onset. C) Incorrect—They are not stronger than corticosteroids. D) Incorrect—They have a black box warning for lymphoma and skin cancer. **CALCINEURIN INHIBITORS** * Two available in Canada Tacrolimus ointment Pimecrolimus cream * Considered second-line therapy but often used clinically as first-line therapy for the face or intertriginous areas * No additive benefit when used in conjunction with corticosteroids * Black box warning pertaining to lymphoma and skin cancer

Answer 7

**✅ Correct Answer: B) Application site pain** Explanation: Crisaborole is a PDE4 inhibitor approved for mild-moderate atopic dermatitis (AD). It has been associated with application site pain, upper respiratory infections (URI), and worsening dermatitis. Wrong choices: A) Incorrect—Skin atrophy is a concern with corticosteroids, not crisaborole. C) Incorrect—The black box warning for lymphoma applies to calcineurin inhibitors, not crisaborole. D) Incorrect—Crisaborole does not cause hyperpigmentation. **CRISABOROLE** * PDE4 inhibitor * The only one approved in Canada at the moment * Approved for use on all body areas in mild-moderate AD * No head-to-head studies exist to objectively determine comparative efficacy to corticosteroids and calcineurin inhibitors * Current studies suggest enhanced benefit over vehicle DLQI: - 5.2 vs – 3.5 * Common AE: application site pain, URI, worsening dermatitis

Answer 8

**✅ Correct Answer: D) Dupilumab Explanation: Dupilumab is a biologic (subcutaneous injection) that reduces IL-4 and IL-13 signaling, which are key in type 2 allergic responses in atopic dermatitis.** Wrong choices: A) Azathioprine is an immunosuppressant, not a biologic. B) Methotrexate is primarily used for RA and some cancers, not IL-4/IL-13 inhibition. C) Cyclosporine is used to prevent organ rejection, not target IL-4/IL-13. **SYSTEMIC THERAPIES** * Dupilumab * Biologic (subcutaneous injection) * Anti IL-4 receptor antibody * Reduces IL-4 and IL-13 signaling * Both are key interleukins involved in type 2 allergic responses, IgE class switching, changes to the epidermal barrier, dermal inflammation and remodeling * Has the potential for marked reductions in SCORAD, EASI, DLQI **Why is increased risk of HSV infection a notable adverse effect?** IL-4 and IL-13 play a role in immune responses against viral infections, including herpes simplex virus (HSV). By inhibiting these cytokines, dupilumab can weaken the body's ability to fight HSV, leading to an increased risk of cold sores (HSV-1) and herpes simplex keratitis. Clinical studies have reported higher rates of HSV infections (including eczema herpeticum) in patients using dupilumab.

Answer 9

**✅ Correct Answer: A) Increased risk of HSV infection** Explanation: Dupilumab has been associated with HSV (herpes simplex virus) infections, conjunctivitis, headache, injection site reactions, and nasopharyngitis. Wrong choices: B) Incorrect—Skin thinning is a steroid-related effect, not dupilumab. C) Incorrect—Organ toxicity is a concern with cyclosporine. D) Incorrect—The black box warning for skin cancer applies to calcineurin inhibitors, not dupilumab.

Answer 10

**✅ Correct Answer: C) Apply topical therapy at the first sign of a flare** Explanation: Flare prevention involves ongoing daily moisturizer use and intermittent topical therapy (1-2 times weekly) to prevent flare-ups. Wrong choices: A) Incorrect—Daily corticosteroid use is stopped after remission. B) Incorrect—Stopping all treatment and waiting for symptoms to return can lead to worse flare-ups. D) Incorrect—Daily calcineurin inhibitor use is not recommended after remission. **FLARE PREVENTION** * Once in remission, the standard is to stop daily topical corticosteroid or calcineurin inhibitors * Ongoing daily use of moisturizer is recommended to prevent flare ups. * Evidence varies for different topical drug therapy regimens - 1-2 times weekly seems sufficient for most patients * Topical therapy should be initiated at the first sign of flare

Answer 11

**✅ Correct Answer: B) Placental metabolism minimizes fetal exposure** Explanation: Low- to mid-potency topical corticosteroids are considered safe during pregnancy because placental metabolism reduces fetal exposure. Wrong choices: A) Incorrect—High-potency corticosteroids are not preferred due to higher systemic absorption. C) Incorrect—Topical corticosteroids are not completely contraindicated. D) Incorrect—Systemic corticosteroids are not the preferred treatment. **Corticoid steroid use in PREGNANCY** * Reliance on nonpharmacologic options preferred * Topical low and mid-potency corticosteroids are the main treatment option - Placental metabolism dramatically minimizes corticosteroid exposure in the developing fetus * Calcineurin inhibitors are safe to use due to low bioavailability when applied topically

Answer 12

**✅ Correct Answer: C) Infant ingestion risk is unknown** Explanation: Calcineurin inhibitors (tacrolimus, pimecrolimus) should not be used on the breast area because the risk of infant ingestion is unknown. Wrong choices: A) Incorrect—They have low systemic absorption, which is why they are safe for other areas. B) Incorrect—The black box warning is for long-term use, not breastfeeding. D) Incorrect—They do not cause significant skin thinning, unlike corticosteroids. * Similar recommendations as with pregnancy * Calcineurin inhibitors are ok when used outside of the breast area * Nipple dermatitis is common - Calcineurin inhibitors should not be used here - Topical corticosteroids cleaned from the area prior to breastfeeding are ok

Answer 13

**Correct Answer: C) Erythema, burning, or stinging ✔ Explanation: These symptoms occur in more than 90% of cases and are the hallmark of topical corticosteroid withdrawal.** ❌ A) Skin peeling → Incorrect, because peeling occurs at the end of a flare, not as the most common symptom. ❌ B) Hives → Incorrect, because hives are less common and more associated with the recovery phase. ❌ D) Papulopustules → Incorrect, though present in 80% of cases, they are slightly less common than erythema, burning, and stinging. **Topical corticosteroid withdrawal SYMPTOMS** * Erythema, burning or stinging are most common and are present in more than 90% of cases * Papulopustules are present in over 80% of cases * Pruritus is present in 45% of cases and can be severe * Skin peeling often occurs at the end of a flare * Hives and excessive sweating can occur and are often signs of recovery * Many other symptoms have been described, including edema, lymphadenopathy, “red sleeve sign,” “headlight sign,” dermal thickening of extensor surfaces

Answer 14

**Correct Answer: C) Application to the face or genitals ✔ Explanation: These areas have thinner skin, which increases absorption and risk of withdrawal symptoms.** ❌ A) Short-term use (less than 4 weeks) → Incorrect, because risk increases with prolonged use, not short-term use. ❌ B) Use of low-potency corticosteroids → Incorrect, because higher potency corticosteroids have a greater risk. ❌ D) Use of topical corticosteroids for insect bites → Incorrect, because occasional use for insect bites is unlikely to cause withdrawal. **Topical corticosteroid RISK FACTORS** * Those with atopic dermatitis are most at risk * Apparent equivalence between men and women when topical steroids are used for inflammatory skin conditions - Topical steroids used for cosmetic reasons inflate the proportion of females affected overall * Application to the face or genitals increases risk * Risk increases with potency of drug and duration of use * Signs of skin damage from topical steroid use often predict the development of steroid withdrawal

Answer 15

Correct Answer: B) Dermal atrophy ✔ Explanation: Long-term use of corticosteroids, especially high-potency ones, can thin the skin, leading to dermal atrophy. ❌ A) Increased risk of infection → Incorrect, because although long-term corticosteroid use can suppress immunity, the main concern in sensitive areas is thinning of the skin. ❌ C) Hyperpigmentation → Incorrect, because while possible, it is not the primary concern. ❌ D) Increased hair growth → Incorrect, because this is more associated with systemic steroids. **Why do corticosteroids cause dermal atrophy?** Corticosteroids cause dermal atrophy because they inhibit the synthesis of collagen and reduce the amount of glycosaminoglycans (such as hyaluronic acid) in the skin. Collagen is a major structural component of the dermis, and its reduction leads to thinning of the skin. Corticosteroids also suppress the fibroblasts, which are responsible for collagen production. Over time, this thinning and weakening of the skin can lead to visible signs like easy bruising, delayed wound healing, and a more fragile skin surface.

Answer 16

Correct Answer: B) Oral antihistamines ✔ Explanation: Antihistamines help relieve pruritus, which is present in 45% of cases and can be severe. ❌ A) Oral gabapentin → Incorrect, because this is more commonly used for burning pain, not pruritus. ❌ C) Topical corticosteroids → Incorrect, because this condition occurs due to corticosteroid use; stopping them is the goal. ❌ D) Topical retinoids → Incorrect, because these can irritate the skin further. **Topical Corticosteroid Withdrawal TREATMENT** * Some studies suggest continued abrupt discontinuation * Other studies suggest tapering the topical corticosteroid * Possible treatment with topical calcineurin inhibitors * Oral antihistamines may help with pruritus * Oral gabapentin may help with burning pain * Sleeping aids and anxiolytics may be appropriate in some cases

Answer 17

**Correct Answer: A) Calcineurin inhibitors ✔ Explanation: These do not cause dermal atrophy, making them useful for delicate areas like the face and skin folds.** ❌ B) Vitamin D derivatives → Incorrect, because they cause irritation and should not be used in skin folds. ❌ C) High-potency corticosteroids → Incorrect, because these should not be used in delicate areas due to atrophy risk. ❌ D) Tar-based products → Incorrect, because these are mainly used for the scalp and guttate psoriasis.

Answer 18

**Correct Answer: C) Biologics ✔ Explanation: All biologics indicated for psoriasis suppress the immune system, increasing infection risk and requiring avoidance of live vaccines.** ❌ A) Apremilast → Incorrect, because it does not significantly suppress the immune system. ❌ B) Methotrexate → Incorrect, because while it affects immunity, it is not as strongly contraindicated with live vaccines as biologics. ❌ D) Acitretin → Incorrect, because it is a retinoid and does not impact live vaccine administration. SYSTEMIC AGENTS - BIOLOGICS * Adverse effects are similar across all biologics indicated for psoriasis * Administration of live vaccines during therapy should be avoided for all biologics indicated for psoriasis

Answer 19

**Correct Answer: A) Methotrexate ✔ Explanation: Methotrexate is teratogenic and contraindicated in pregnancy due to its effects on folate metabolism.** ❌ B) Apremilast → Incorrect, because while it has side effects, it is not a strong teratogen. ❌ C) Cyclosporine → Incorrect, because while it has risks, it is not as strongly contraindicated in pregnancy as methotrexate. ❌ D) Roflumilast → Incorrect, because this is a PDE4 inhibitor with minimal systemic toxicity. **SYSTEMIC AGENTS - IMMUNOSUPPRESSIVES** * Methotrexate * Commonly used and cost-effective agent for psoriasis * Can be a safe and effective treatment with appropriate patient selection (avoid in pregnancy, presence or risk of liver disease, active or chronic infection including hepatitis B or C, tuberculosis) and monitoring (CBC, liver enzymes, renal function) **Psoriasis SYSTEMIC AGENTS** * When topical agents do not achieve the desired benefit or when psoriasis is quite severe, systemic agents are indicated * Oral retinoids * Biologics * Immunosuppressants

Answer 20

**Correct Answer: A) Increased risk of intracranial pressure with tetracyclines ✔ Explanation: Acitretin + tetracyclines can cause pseudotumor cerebri, a condition of increased intracranial pressure.** ❌ B) Increased risk of hypertension → Incorrect, because this is more associated with cyclosporine. ❌ C) Increased risk of hypoglycemia → Incorrect, because acitretin does not impact blood sugar regulation. ❌ D) Increased risk of osteoporosis → Incorrect, because this is more linked to systemic corticosteroids, not acitretin. **SYSTEMIC AGENTS - IMMUNOSUPPRESSIVES** * Acitretin * Adverse effects include joint and muscle pain, mucosal dryness, hepatoxicity requiring liver function monitoring, hyperlipidemia * Alcohol consumption increases conversion of acitretin to a long half-life metabolite etretinate. - Significant biologic persistence potentially requiring an extension of time after discontinuation before pregnancy is advised * Increased risk of liver damage when combined with methotrexate * Elevated risk of increased intracranial pressure when used with tetracyclines

Answer 21

**Correct Answer: A) GI side effects ✔ Explanation: Apremilast (PDE4 inhibitor) causes nausea, diarrhea, and weight loss, especially during dose titration.** ❌ B) Hepatotoxicity → Incorrect, because this is more associated with methotrexate. ❌ C) Hyperkalemia → Incorrect, because this is a side effect of cyclosporine. ❌ D) Bone marrow suppression → Incorrect, because this is a concern with methotrexate, not apremilast. **SYSTEMIC AGENTS - IMMUNOSUPPRESSIVES** * Apremilast * PDE4 Inhibitor * Significant GI adverse effects that can be minimized by titrating up to therapeutic dose over 5 days - Other AE: URI, headache, weight loss * Reduced levels with CYP3A4 inducers * May be a more appropriate choice in medically complex patients where other systemic nonbiologic agents carry a greater risk of toxicity

Answer 22

**Correct Answer: B) Because narrowband UVB (nbUVB) phototherapy combined with tar and salicylic acid is the most effective for guttate psoriasis. Tar helps reduce scaling, and salicylic acid acts as a descaling agent.** A is incorrect because anthralin is primarily used for chronic plaque psoriasis and often irritates the skin. C is incorrect because calcineurin inhibitors are not approved for psoriasis and are mainly used for delicate areas like the face and folds. D is incorrect because methotrexate is a systemic agent reserved for moderate-to-severe psoriasis, not guttate psoriasis. TOPICAL DRUG THERAPY * Topical medium-potency corticosteroids are usually the drug of choice for psoriasis on the body or extremities * If topical corticosteroids do not achieve the desired benefit, vitamin D derivatives, tazarotene, tar, and anthralin can be used in isolation or in combination. * nbUVB phototherapy with tars and salicylic acid (descaling agent) is most effective for guttate psoriasis

Answer 23

**Correct Answer: C) Lotions or gels because lotions and gels are best suited for the scalp, as they are easier to apply and absorb well.** A is incorrect because ointments are greasy and difficult to wash out of hair. B is incorrect because creams are not ideal for the scalp due to their thicker consistency. D is incorrect because while tar-based shampoos help with scale removal, they are not a standalone treatment.

Answer 24

**Correct Answer: C) because, like biologics, deucravacitinib requires caution with live vaccines.** A is incorrect because deucravacitinib is a tyrosine kinase 2 (TK2) inhibitor, not an IL-23 biologic. B is incorrect because while it may be more effective than apremilast, it has a risk of infections (URTI, herpes simplex) and other side effects. D is incorrect because PDE-4 inhibitors (e.g., apremilast) work differently from TK2 inhibitors.

Answer 25

Correct Answer: C) High-potency corticosteroids 👉 Why? The palms and soles have thicker skin, so higher potency corticosteroids are required to penetrate effectively and treat skin conditions. ❌ Wrong Answers: A) Low-potency corticosteroids would not be sufficient for thick skin areas like the palms and soles. B) Moderate-potency corticosteroids might not be strong enough for these areas. D) No corticosteroids should not be used; higher-potency corticosteroids are needed for treatment. **MODIFICATIONS FOR SKIN TYPES** * Face and skin folds - Dermal atrophy is the biggest concern - Lower potency corticosteroids (hydrocortisone 1%) or calcineurin inhibitors - The frequency of application should be reduced as improvement occurs * Palms and Soles - Higher potency corticosteroids are needed, given the thickness of the skin in these areas - Quite difficult to treat

Answer 26

**Correct Answer: A) Clindamycin 👉 Why? Clindamycin is the most commonly used topical antibiotic for acne treatment. It helps reduce bacterial growth, which is a key factor in acne development. It's often combined with other agents like benzoyl peroxide to reduce antibiotic resistance.** Explanation of the other options: B) Benzoyl peroxide: While it is not an antibiotic, it is often used as an antibacterial and comedolytic agent. It helps to clear existing acne and prevent new lesions by killing acne-causing bacteria and opening up clogged pores. However, it is not classified as an antibiotic like clindamycin. C) Tretinoin: A topical retinoid that is potent and effective for treating acne but is not an antibiotic. It's used to help prevent acne formation by promoting skin cell turnover. D) Adapalene: Another topical retinoid, least irritating compared to tretinoin, but not an antibiotic. It helps in reducing comedones (clogged pores) and treating acne.

Answer 27

**Correct Answer: B) Minocycline 👉 Why? Minocycline has a known risk of causing drug-induced lupus and hepatitis, making it a less preferred option among the tetracycline family. ❌ Wrong Answers:** A) Doxycycline is a preferred first-line agent and has fewer severe side effects compared to minocycline. C) Tetracycline is another tetracycline, but minocycline has a higher risk profile for lupus and hepatitis. D) Azithromycin is a macrolide and is generally reserved for second-line use, not known for causing lupus or hepatitis. **SYSTEMIC AGENTS for Acne** * Antibiotics - Tetracyclines first-line agents - Doxycycline, minocycline, tetracycline Minocycline is the worst option due to drug-induced lupus and hepatitis * Macrolides and SMX-TMP should only be used as second-line options if tetracyclines are contraindicated or do not work - Conservative use to minimize resistance * Should be used in conjunction with benzoyl peroxide

Answer 28

**Correct Answer: C) To eradicate the infection and prevent complications 👉 Why? The main goal of treating a bacterial skin infection is to eradicate the infection and prevent complications like abscess formation or systemic spread. ❌ Wrong Answers:** A) While preventing new infections is important, the primary goal is to address the current infection. B) Relieving symptoms is a secondary goal once the infection is under control. D) Increasing hydration may be beneficial, but it is not the primary goal of infection treatment. **GOALS OF THERAPY for Treating Acne** * Clear existing lesions * Prevent new lesions * Minimize scarring * Reduce dyspigmentation * Minimize psychological impact

Answer 29

Correct Answer: A) Mupirocin 👉 Why? Mupirocin is an effective topical antibiotic commonly used for treating mild staphylococcal folliculitis. ❌ Wrong Answers: B) Cephalexin is used for more extensive cases of folliculitis, not mild ones. C) Clindamycin is another good option but typically used in more extensive cases. D) Tetracycline is usually used for systemic infections rather than topical issues.

Answer 30

**Correct Answer: B) Eliminating tight-fitting clothing and reducing friction 👉 Why? Folliculitis can be exacerbated by friction, moisture, and heat, so removing contributing factors like tight clothing is an effective nonpharmacologic treatment.** ❌ Wrong Answers: A) Topical antibiotics can be used, but they are pharmacological treatments, not nonpharmacologic. C) Increasing friction would worsen folliculitis, not treat it. D) Steroids should not be used in treating folliculitis without proper medical evaluation.

Answer 31

**Correct Answer: B) Mupirocin 👉 Why? Mupirocin is a topical antibiotic commonly used to treat infections caused by Staphylococcus aureus, including folliculitis.** ❌ Wrong Answers: A) Clindamycin is also an option but may not be as specific as mupirocin for staph infections. C) Tetracycline is an oral antibiotic, not topical, and is used for more extensive cases. D) Benzoyl peroxide is used for acne, not bacterial folliculitis.

Answer 32

**Correct Answer: B) Doxycycline 👉 Why? Doxycycline is effective against MRSA and is a common second-line treatment for skin infections like carbuncles and furuncles.** ❌ Wrong Answers: A) Cephalexin is effective for staph infections but not MRSA. C) Amoxicillin is not effective against MRSA. D) Erythromycin is not the first choice for MRSA and is less commonly used for this purpose.

Answer 33

**Correct Answer: B) Ensuring adequate chlorination of the water to prevent recurrence 👉 Why? Hot tub folliculitis is often caused by Pseudomonas aeruginosa, and ensuring the water is adequately chlorinated can help prevent further outbreaks.** ❌ Wrong Answers: A) Antibiotics are typically not needed for hot tub folliculitis unless it's severe. C) Oral contraceptives have no role in preventing folliculitis. D) Topical steroids should be avoided in the case of folliculitis unless directed by a physician. **What is FOLLICULITIS** * Inflammation of superficial or deep hair follicles, producing papules and pustules * Infectious causes include - Staphylococcus aureus (most common) - Pseudomonas aeruginosa (hot tub–associated) - Other gram-negative rods (sometimes after prolonged antibiotic use)

Answer 34

Correct Answer: A) Topical retinoids 👉 Why? Topical retinoids, like tretinoin, are teratogenic and should be avoided during pregnancy due to potential harm to the fetus. ❌ Wrong Answers: B) Oral erythromycin is considered safe to use during pregnancy for bacterial infections. C) Mupirocin is safe for topical use during pregnancy. D) Benzoyl peroxide is considered safe for topical use during pregnancy

Answer 35

**Correct Answer: B) Isotretinoin 👉 Why? Isotretinoin is highly effective for severe acne but is a potent teratogen. Strict precautions, including pregnancy tests and contraception, are required.** ❌ Wrong Answers: A) Doxycycline is effective for acne but does not carry the same teratogenic risks. C) Spironolactone is used off-label for acne but is not teratogenic to the same degree as isotretinoin. D) Tetracycline, while effective for acne, is not as commonly prescribed as isotretinoin for severe cases and does not require the same strict pregnancy precautions.

Answer 36

**Correct Answer: C) Topical retinoids 👉 Why? Topical retinoids should not be used during pregnancy due to the risk of birth defects.** ❌ Wrong Answers: A) Benzoyl peroxide is safe during pregnancy for topical acne treatment. B) Oral erythromycin is considered safe during pregnancy for bacterial infections. D) Clindamycin is safe for topical use during pregnancy for acne. TOPICAL AGENTS * Topical retinoids should not be combined with benzoyl peroxide at the same time Benzoyl peroxide in AM and topical retinoid before bed is ok * Other comedolytics Azelaic acid – also reduced pigmentation Salicylic acid – usually found in OTC cosmetic products Glycolic acid – suitable alternative to topical retinoids **SYSTEMIC AGENTS for Acne** * Antibiotics - Tetracyclines first-line agents - Doxycycline, minocycline, tetracycline Minocycline is the worst option due to drug-induced lupus and hepatitis * Macrolides and SMX-TMP should only be used as second-line options if tetracyclines are contraindicated or do not work - Conservative use to minimize resistance * Should be used in conjunction with benzoyl peroxide * Oral contraceptives Specifically ones with minimal androgenic activity or those that contain cyproterone acetate or drospirenone * Spironolactone Potassium sparing diuretic Often prescribed off label due to its anti-androgenic effects

Answer 37

**Correct Answer: A) Malassezia 👉 Why? Malassezia is a type of yeast that can cause fungal folliculitis, which is not related to bacterial infection. ❌ Wrong Answers:** B) Staphylococcus aureus causes bacterial folliculitis, not fungal. C) Streptococcus pyogenes is a bacteria that causes impetigo, not folliculitis. D) Escherichia coli is not a common cause of folliculitis.

Answer 38

**Correct Answer: B) A collection of multiple interconnected boils 👉 Why? A carbuncle is formed when multiple furuncles (boils) merge into a large purulent mass.** ❌ Wrong Answers: A) A single boil refers to a furuncle, not a carbuncle. C) A fungal infection is not associated with carbuncles; they are bacterial. D) A superficial skin infection doesn't describe the deep, interconnected nature of a carbuncle.

Answer 39

**Correct Answer: C) Elimination of tight-fitting clothing 👉 Why? Reducing friction, moisture, and heat by wearing looser clothing can help prevent folliculitis, especially in intertriginous regions.** ❌ Wrong Answers: A) Warm compresses are used to treat furuncles and carbuncles, but not for all cases of folliculitis. B) Antibiotics are not used for all cases of folliculitis, as mild cases may resolve on their own. D) Surgical drainage is used in severe cases (like carbuncles), but not typically for folliculitis.

Answer 40

**Correct Answer: A) Mupirocin 👉 Why? Mupirocin is an effective topical antibiotic, especially for folliculitis caused by Staphylococcus aureus.** ❌ Wrong Answers: B) Amoxicillin is a broad-spectrum antibiotic but is not typically used topically for folliculitis. C) Ciprofloxacin is a fluoroquinolone used for systemic infections, not typically for topical folliculitis. D) Clindamycin can also be used but is more often prescribed for oral use in more severe cases.

Answer 41

**Correct Answer: A) Cephalexin for 7 days 👉 Why? In extensive or persistent folliculitis, oral antibiotics like cephalexin are recommended to target the bacterial infection effectively.** ❌ Wrong Answers: B) Mupirocin ointment is for localized cases and not for extensive infections. C) Oral antifungals are not indicated for bacterial folliculitis, which is treated with antibiotics. D) Warm compresses are used for furuncles or carbuncles, not for extensive bacterial folliculitis.

Answer 42

**Correct Answer: B) Perform a culture to identify the cause 👉 Why? If MRSA (methicillin-resistant Staphylococcus aureus) is suspected, it is essential to culture the infection first to confirm the bacteria and determine appropriate treatment.** ❌ Wrong Answers: A) Administer oral antibiotics without culture is not recommended as it may not target the right bacteria. C) Treat with antifungals is incorrect because MRSA is a bacterial infection, not fungal. D) Use over-the-counter antibiotics may not be effective against MRSA.

Answer 43

**Correct Answer: A) Group A beta-hemolytic streptococci (S. pyogenes) 👉 Why? Nonpurulent cellulitis is predominantly caused by Group A beta-hemolytic streptococci, such as S. pyogenes.** ❌ Wrong Answers: B) Staphylococcus aureus is the cause of purulent cellulitis, not nonpurulent. C) Haemophilus influenzae is linked to buccal cellulitis in children, not typically to cellulitis. D) Pasteurella and Capnocytophaga are associated with cellulitis caused by animal bites, not nonpurulent cellulitis.

Answer 44

**Correct Answer: B) Elevation of the affected area 👉 Why? Elevating the affected area helps to reduce edema and promote healing.** ❌ Wrong Answers: A) Oral antibiotics are a pharmacologic treatment, not a nonpharmacologic one. C) Incision and drainage is a procedure for abscesses, not cellulitis. D) Antifungal creams are not appropriate for cellulitis, as it is a bacterial infection, not fungal.

Answer 45

**Correct Answer: B) Cephalexin 👉 Why? Cephalexin, a first-generation cephalosporin, is effective against S. pyogenes and is the first-line treatment for nonpurulent cellulitis.** ❌ Wrong Answers: A) Mupirocin is a topical antibiotic and is not used for cellulitis, which often requires systemic therapy. C) Fluconazole is an antifungal, not appropriate for bacterial cellulitis. D) Amoxicillin/clavulanic acid is used for animal bites and polymicrobial infections, not for simple nonpurulent cellulitis.

Answer 46

**Correct Answer: A) Hyperhidrosis 👉 Why? Hyperhidrosis (excessive sweating) is a known risk factor for onychomycosis, as it creates a moist environment conducive to fungal growth.** ❌ Wrong Answers: B) Cold weather is not a risk factor for fungal nail infections. C) Dehydration may affect skin health, but it is not directly linked to fungal nail infections. D) Decreased foot temperature is not a significant factor in fungal nail infections.

Answer 47

**Correct Answer: C) Distal subungual onychomycosis (DLSO) 👉 Why? DLSO is the most common subtype of onychomycosis, accounting for about 90% of cases.** ❌ Wrong Answers: A) Superficial white onychomycosis is less common and typically affects children. B) Proximal subungual onychomycosis is rare and often seen in immunocompromised individuals. D) Candida onychomycosis is caused by yeast, not dermatophytes, and is less common than DLSO.

Answer 48

**Correct Answer: B) Ciclopirox olamine 8% lacquer 👉 Why? Ciclopirox is a topical treatment specifically used for onychomycosis, applied to the nails for an extended period to improve nail appearance.** ❌ Wrong Answers: A) Oral terbinafine is a systemic treatment, often reserved for more severe cases. C) Fluconazole is an oral antifungal, not a topical treatment. D) Itraconazole is also a systemic treatment, typically used when topical therapy is ineffective.

Answer 49

**Correct Answer: A) Eradicate the causative organism and achieve mycological cure 👉 Why? The primary goal is to eliminate the fungal infection and achieve mycological cure, which is confirmed through laboratory tests.** ❌ Wrong Answers: B) Prevent systemic side effects is important but not the primary goal. C) Reduce nail thickness is a secondary goal; the main aim is to cure the infection. D) Apply topical treatments to the skin does not address the fungal infection in the nail effectively.

Answer 50

**Correct Answer: C) Terbinafine 👉 Why? Terbinafine is the most effective and preferred systemic treatment for dermatophyte-related onychomycosis.** ❌ Wrong Answers: A) Fluconazole is less effective for dermatophytes and not the first choice for onychomycosis. B) Itraconazole is second-line for dermatophyte infections, preferred for yeast or nondermatophyte moulds. D) Griseofulvin is an older treatment and is less effective compared to terbinafine.

Pharmacology for Dermatology Flashcards

(74 cards)