196: Other Topical Medications Flashcards
1
Q
What are the primary uses of topical capsaicin?
A
Topical capsaicin is used to treat:
- Postherpetic neuralgia
- Diabetic neuropathy
- Reflex sympathetic dystrophy
- Raynaud phenomenon
- Osteoarthritis
- Plantar warts
- Diabetic neuralgia
- Localized pruritus of neuropathic origin
2
Q
What are the key considerations when using EMLA cream?
A
Key considerations for EMLA cream (lidocaine 2.5% and prilocaine 2.5%):
1. Apply under occlusion to intact skin or genital mucous membranes for at least 1 hour before a painful procedure.
2. Provides local anesthesia that may last up to 2 hours.
3. Should not be used in patients with hypersensitivity to amide anesthetics.
4. Side effects are generally mild skin reactions.
5. Rare severe complications include CNS toxicity and methemoglobinemia.
3
Q
What are the potential side effects of lidocaine as a topical anesthetic?
A
Potential side effects of lidocaine include:
- Local skin irritation (erythema, edema, bruising)
- Systemic toxicity, especially from high concentrations (30%) which can lead to CNS and cardiac effects such as seizures, coma, and arrhythmia.
- Pregnancy category B drug, indicating it is generally considered safe during pregnancy.
4
Q
How does coal tar function in the treatment of inflammatory dermatoses?
A
Coal tar functions by:
- Inhibiting DNA synthesis and mitosis in epidermal cells, enhanced by UV exposure.
- Providing antiinfective, antipruritic, photosensitizing, and vasoconstrictive effects.
- Activating the aryl hydrocarbon receptor, inducing epidermal differentiation.
- Counteracting T-helper type-2 cytokine-mediated downregulation of skin barrier proteins.
5
Q
What are the uses and effects of wood tar in dermatological conditions?
A
Wood tar is used for:
- Atopic dermatitis
- Psoriasis (especially of the scalp)
- Seborrheic dermatitis
Effects include:
- Antibacterial, antiinflammatory, antifungal, and antipruritic activity.
- May result in contact sensitivity.
6
Q
What is the mechanism of action of shale oil in treating skin conditions?
A
Shale oil works by:
- Decreasing inflammation through the inhibition of leukotriene B4 lipoxygenase.
- Used to treat conditions such as venous leg ulcers, acne, psoriasis, seborrhea, eczema, rosacea, and pruritus.
- Generally well tolerated, with skin irritation being the most common side effect.
7
Q
What are the benefits of crisaborole in treating atopic dermatitis?
A
Crisaborole is beneficial for atopic dermatitis because:
- It reduces skin inflammation by inhibiting phosphodiesterase 4.
- Clinical trials show it is more effective than vehicle in reducing disease severity and improving pruritus in patients with mild to moderate atopic dermatitis.
- Generally well tolerated with no severe adverse effects reported.
8
Q
A patient with postherpetic neuralgia is experiencing intense burning after applying a topical medication. Which medication is likely causing this, and what is its primary side effect?
A
The medication is capsaicin, and its primary side effect is irritation and an intense burning sensation.
9
Q
What precautions should be taken when using EMLA cream for local anesthesia?
A
EMLA cream should not be used in patients with hypersensitivity to amide anesthetics. Factors increasing systemic toxicity risk include excessive application, longer application time, and application to inflamed skin. It is ototoxic and should not be used near the tympanic membrane.
10
Q
A patient with psoriasis is prescribed coal tar. What are the potential local adverse effects of this treatment?
A
Local adverse effects of coal tar include tar folliculitis, acneiform eruptions, irritant dermatitis, burning, stinging, allergic contact dermatitis, atrophy, telangiectases, pigmentation, exfoliative dermatitis, and keratoacanthomas.
11
Q
What are the potential systemic effects of lidocaine when used topically, and what precautions should be taken?
A
Systemic effects include CNS and cardiac effects such as seizures, coma, arrhythmia, apnea, and death. Precautions include avoiding excessive application and monitoring for signs of systemic toxicity.
12
Q
What is the mechanism of action of crisaborole, and for which condition is it commonly used?
A
Crisaborole reduces skin inflammation by inhibiting phosphodiesterase 4. It is commonly used for mild to moderate atopic dermatitis.
13
Q
What are the side effects associated with EMLA cream?
A
The side effects of EMLA cream include:
- Mild skin reactions
- Rare severe complications such as CNS toxicity, cardiotoxicity, and methemoglobinemia (due to prilocaine)
14
Q
What precautions should be taken when using EMLA cream?
A
Precautions for using EMLA cream include:
1. Avoid in patients with hypersensitivity to amide anesthetics.
2. Use caution in patients susceptible to systemic effects (e.g., acutely ill, elderly).
3. Avoid excessive application, prolonged use, and application to inflamed skin.
4. Not to be used if there is a risk of penetrating the tympanic membrane.
15
Q
What is the primary mechanism of action of coal tar in treating skin conditions?
A
Coal tar works by:
- Inhibiting DNA synthesis and mitosis in epidermal cells.
- Activating the aryl hydrocarbon receptor, inducing epidermal differentiation.
- Counteracting T-helper type-2 cytokine-mediated downregulation of skin barrier proteins.
16
Q
What are the common local adverse effects of coal tar?
A
Common local adverse effects of coal tar include:
- Tar folliculitis
- Acneiform eruptions
- Irritant dermatitis
- Burning and stinging
- Allergic contact dermatitis
- Atrophy
- Telangiectases
- Pigmentation changes
- Exfoliative dermatitis
- Keratoacanthomas.
17
Q
What are the therapeutic uses of wood tar?
A
Wood tar is used for:
- Atopic dermatitis
- Psoriasis (especially of the scalp)
- Seborrheic dermatitis
- Other inflammatory skin conditions.
18
Q
What is the mechanism of action of shale oil in treating skin conditions?
A
Shale oil decreases inflammation by inhibiting leukotriene B4 lipoxygenase, which helps in treating conditions like venous leg ulcers, acne, psoriasis, seborrhea, eczema, rosacea, and pruritus.
19
Q
What is crisaborole and its primary use?
A
Crisaborole is a boron-containing, novel small molecule that reduces skin inflammation by inhibiting phosphodiesterase 4. It is primarily used to treat mild to moderate atopic dermatitis.
20
Q
What are the reported side effects of crisaborole?
A
Crisaborole is generally well tolerated, with no severe adverse effects reported as of the latest information.
21
Q
What are the systemic effects that may occur with topical lidocaine?
A
Systemic effects from topical lidocaine may include:
- CNS effects (e.g., seizures, coma)
- Cardiac effects (e.g., arrhythmia, apnea)
- Death in severe cases.
22
Q
What are the contraindications for using lidocaine topical products?
A
Lidocaine topical products should not be used in patients with:
- Hypersensitivity to lidocaine
- Certain systemic conditions that may increase the risk of toxicity.
23
Q
What is the recommended application method for EMLA cream before a painful procedure?
A
EMLA cream should be applied under occlusion to intact skin or genital mucous membranes for at least 1 hour before the performance of a painful procedure.
24
Q
What is the pregnancy category of lidocaine and EMLA cream?
A
Both lidocaine and EMLA cream are classified as Pregnancy Category B drugs, indicating that they are generally considered safe for use during pregnancy.
25
What are the potential systemic complications of using EMLA cream?
Potential systemic complications of using EMLA cream include:
- CNS toxicity
- Cardiotoxicity
- Methemoglobinemia (due to prilocaine).
26
What is the primary side effect of capsaicin?
The chief side effect of capsaicin is irritation and an intense burning sensation at the application site.
27
What are the common uses of lidocaine topical products?
Lidocaine topical products are commonly used to treat:
- Localized neuropathic pain
- Postherpetic neuralgia
- Diabetic polyneuropathy.
28
What is the effect of coal tar on skin barrier proteins?
Coal tar counteracts T-helper type-2 cytokine-mediated downregulation of skin barrier proteins, which helps in treating inflammatory skin conditions.
29
What are the adverse effects associated with wood tar?
Adverse effects of wood tar may include:
- Contact sensitivity
- Local irritation.
30
What is the significance of the aryl hydrocarbon receptor in the action of coal tar?
The aryl hydrocarbon receptor is significant in coal tar's action as it activates pathways that induce epidermal differentiation, aiding in the treatment of skin conditions.
31
What are the common side effects of using lidocaine topical products?
Common side effects of lidocaine topical products include:
- Local skin irritation (e.g., erythema, edema, bruising).
32
What is the role of crisaborole in the treatment of atopic dermatitis?
Crisaborole plays a role in reducing disease severity and improving pruritus in patients with mild to moderate atopic dermatitis, as shown in clinical trials.
33
What is the primary action of coal tar in treating psoriasis?
Coal tar primarily acts by inhibiting DNA synthesis and mitosis in epidermal cells, which helps reduce the symptoms of psoriasis.
34
What are the potential systemic effects of topical lidocaine at high concentrations?
At high concentrations, topical lidocaine can lead to severe systemic effects such as:
- CNS effects (e.g., seizures, coma)
- Cardiac effects (e.g., arrhythmia, apnea)
- Death.
35
What is the mechanism of action of wood tar in treating skin conditions?
Wood tar works by reducing DNA synthesis and mitotic activity, providing antibacterial, anti-inflammatory, antifungal, and antipruritic effects.
36
What are the indications for using shale oil in dermatological treatments?
Shale oil is indicated for treating:
- Venous leg ulcers
- Acne
- Psoriasis
- Seborrhea
- Eczema
- Rosacea
- Pruritus.
37
What is the primary benefit of using crisaborole over traditional treatments for atopic dermatitis?
Crisaborole has been found to be more effective than vehicle treatments in reducing disease severity and improving pruritus in patients with mild to moderate atopic dermatitis.
38
What are the common local adverse effects of using coal tar?
Common local adverse effects of coal tar include:
- Folliculitis
- Acneiform eruptions
- Irritant dermatitis
- Burning and stinging.
39
What is the significance of the systemic effects of coal tar in treatment?
The systemic effects of coal tar are generally uncommon, making it a relatively safe option for treating inflammatory dermatoses, although local adverse effects can occur.
40
What are the contraindications for using coal tar?
Coal tar should be used with caution in patients with:
- Known allergies to coal tar or its components
- Active skin infections in the area of application.
41
What is the role of phosphodiesterase 4 inhibition in the action of crisaborole?
Inhibiting phosphodiesterase 4 reduces inflammation in the skin, which is beneficial in treating atopic dermatitis.
42
What is the mechanism of action of mupirocin and its clinical significance?
Mupirocin prevents the incorporation of isoleucine into proteins by inhibiting bacterial isoleucyl tRNA synthetase. This unique mechanism results in no cross-resistance with other antimicrobials, making it effective against staphylococci, streptococci, and certain Gram-negative bacteria, particularly for treating nonbullous impetigo and eliminating S. aureus nasal colonization.
43
What are the primary uses and properties of chlorhexidine in topical applications?
Chlorhexidine gluconate is a bisbiguanide with rapid onset that binds to the stratum corneum. It has fungicidal and broad-spectrum bactericidal activity against Gram-negative and Gram-positive organisms. It is used as an antiseptic, disinfectant, and antibacterial dental rinse, but is not recommended for preoperative preparation of the face or head due to its ototoxicity and risk of conjunctivitis.
44
What are the clinical applications and side effects of azelaic acid?
Azelaic acid is used for its antimicrobial effects against Propionibacterium acnes and Staphylococcus epidermidis, making it effective for treating acne and rosacea. It normalizes keratinization and has a direct anti-inflammatory effect. It is classified as a pregnancy category B drug and is often preferred for treating acne or rosacea in pregnant patients.
45
What are the characteristics and uses of hydrogen peroxide in dermatology?
Hydrogen peroxide serves as a cleansing agent and is used for the removal of debris. It has antibacterial properties against both Gram-positive and Gram-negative bacteria, and its effervescent quality helps debride wounds, making it useful in wound care.
46
What is the significance of benzoyl peroxide in acne treatment?
Benzoyl peroxide is commonly used in the treatment of acne vulgaris. It reduces the size of comedones, increases sebum excretion, and has bactericidal effects against P. acnes. To limit antibiotic resistance, it is often combined with topical antibiotics, and it is classified as a pregnancy category C drug.
47
Which topical antimicrobial agent is effective against methicillin-resistant Staphylococcus aureus and Candida species but may cause skin necrosis at high concentrations?
Gentian violet is effective against methicillin-resistant Staphylococcus aureus and Candida species but may cause skin necrosis at concentrations greater than 2%.
48
A patient with rosacea is prescribed metronidazole. What is its mechanism of action in treating this condition?
Metronidazole impedes leukocyte chemotaxis and selectively suppresses cellular immunity, in addition to its antibiotic properties.
49
What is the unique mechanism of action of mupirocin, and for which conditions is it the treatment of choice?
Mupirocin prevents the incorporation of isoleucine into proteins by inhibiting bacterial isoleucyl tRNA synthetase. It is the treatment of choice for nonbullous impetigo and effective in eliminating S. aureus nasal colonization.
50
A pregnant patient with acne is seeking treatment. Which topical agent is preferred, and why?
Azelaic acid is preferred because it is a pregnancy category B drug and has antimicrobial effects against Propionibacterium acnes and Staphylococcus epidermidis.
51
What are the potential systemic side effects of chlorhexidine, and why is it not recommended for preoperative preparation of the face or head?
Systemic side effects include ototoxicity and the risk of conjunctivitis and corneal ulceration. It is not recommended for preoperative preparation of the face or head due to these risks.
52
What is the mechanism of action of benzoyl peroxide in treating acne, and how does it help limit antibiotic resistance?
Benzoyl peroxide reduces comedones, increases sebum excretion, and has bactericidal effects. It is often combined with topical antibiotics to reduce the development of antibiotic resistance by P. acnes.
53
What is the mechanism of action of retapamulin, and for which conditions is it effective?
Retapamulin inhibits the elongation phase of protein synthesis by selectively binding to the 50S subunit of prokaryotic ribosomes.
54
What is the mechanism of action of retapamulin, and for which conditions is it effective?
Retapamulin inhibits the elongation phase of protein synthesis by selectively binding to the 50S subunit of prokaryotic ribosomes. It is effective against methicillin-sensitive S. aureus and Streptococcus pyogenes.
55
What is the mechanism of action of mupirocin and its clinical significance in treating skin infections?
Mupirocin prevents the incorporation of isoleucine into proteins by inhibiting bacterial isoleucyl tRNA synthetase. This unique mechanism results in no cross-resistance with other antimicrobials, making it effective against staphylococci and streptococci, and it is the treatment of choice for nonbullous impetigo and effective in eliminating S. aureus nasal colonization.
56
What are the potential side effects of retapamulin and its clinical applications?
Retapamulin can cause irritant and contact dermatitis. It is effective against certain Gram-positive bacteria, particularly for treating methicillin-sensitive S. aureus and Streptococcus pyogenes, and is prescribed as a 1% topical ointment.
57
How does azelaic acid function in the treatment of acne and rosacea, and what is its pregnancy category?
Azelaic acid acts as a competitive inhibitor of tyrosinase and has antimicrobial effects against Propionibacterium acnes and Staphylococcus epidermidis. Its efficacy is attributed to normalizing keratinization and providing a direct anti-inflammatory effect. It is classified as a pregnancy category B drug, often preferred for treating acne or rosacea in pregnant patients.
58
What are the clinical implications of using chlorhexidine as an antiseptic, and what precautions should be taken?
Chlorhexidine is a broad-spectrum antiseptic with residual activity for over 6 hours, effective against Gram-positive and Gram-negative organisms. However, it is ototoxic and can cause conjunctivitis and corneal ulceration, thus it is not recommended for preoperative preparation of the face or head.
59
What are the advantages and disadvantages of using hydrogen peroxide in wound care?
Hydrogen peroxide serves as a cleansing agent and helps remove debris, with antibacterial properties against both Gram-positive and Gram-negative bacteria. However, its effervescent quality can help debride wounds, but it may also damage healthy tissue if used excessively.
60
What are the indications for using metronidazole in dermatology, particularly for rosacea?
Metronidazole is used for its activity against anaerobic bacteria and protozoa, particularly in treating rosacea. Its mode of action may involve the suppression of leukocyte chemotaxis and cellular immunity, making it effective in managing inflammatory lesions associated with rosacea.
61
What are the properties and clinical uses of povidone-iodine in dermatological practice?
Povidone-iodine has a wide spectrum of in vitro activity against Gram-negative and Gram-positive bacteria, fungi, and viruses. It is commonly used as a topical antiseptic, but systemic absorption can lead to renal and thyroid dysfunction if used in large or prolonged quantities.
62
What are the characteristics of dyes used in dermatology, and what precautions should be taken?
Dyes such as gentian violet and brilliant green are inexpensive and effective against Candida species and aerobic Gram-positive bacteria. However, gentian violet can cause skin necrosis in concentrations greater than 2% and is a known contact sensitizer, necessitating caution in its use.
63
What is the mechanism of action of Ivermectin as an antiparasitic agent?
Ivermectin works by binding to glutamate-gated and aminobutyric acid-gated chloride ion channels of parasite nerve and muscle cells, leading to increased permeability of chloride ions, resulting in paralysis and death of the parasites.
64
What are the pregnancy categories for Crotamiton and Permethrin?
Crotamiton is classified as a Pregnancy category C drug, while Permethrin is classified as a Pregnancy category B drug.
65
What are the side effects associated with Lindane use?
Lindane can cause multiple side effects including CNS toxicity, seizures, and aplastic anemia. It should be avoided in patients with seizure disorders, children weighing less than 50 kg, and those with acutely inflamed or raw skin.
66
How does Spinosad function as an insecticide?
Spinosad is a fermentation product that causes widespread excitation of the insect CNS, leading to paralysis. It disrupts acetylcholine transmission and acts as an aminobutyric acid agonist.
67
What is the recommended application method for Aluminum Compounds in treating hyperhidrosis?
Aluminum compounds are typically applied topically for 1 week at night when eccrine glands are less active. If tolerated, it can be applied up to twice daily. After achieving control, it can be applied every 1 to 3 weeks as maintenance therapy.
68
What is the clinical significance of using Glycopyrrolate for hyperhidrosis?
Glycopyrrolate is an anticholinergic agent that blocks muscarinic receptors, inhibiting cholinergic transmission. It is increasingly used as a topical therapy for hyperhidrosis, particularly for facial and axillary areas, showing similar efficacy to botulinum toxin type-A injections when evaluated at 6 weeks.
69
What is the mechanism of action of ivermectin in treating scabies, and how does it compare to permethrin?
Ivermectin binds to glutamate-gated and GABA-gated chloride ion channels, leading to increased permeability, paralysis, and death of parasites. Topical 1% ivermectin is as effective as 2.5% permethrin cream when applied twice with a 1-week interval.
70
A patient with head lice is prescribed spinosad. What is its mechanism of action, and how does it compare to permethrin?
Spinosad causes widespread excitation of the insect CNS, leading to paralysis by disrupting acetylcholine transmission and acting as a GABA agonist. Spinosad 0.9% cream is superior to 1% permethrin cream for head lice treatment.
71
What is the recommended application protocol for aluminum chloride in treating hyperhidrosis, and what is a common adverse effect?
Aluminum chloride is applied topically at night for 1 week and, if tolerated, up to twice daily. A common adverse effect is skin irritation.
72
A patient with scabies is prescribed permethrin. What is its mechanism of action, and how is it applied?
Permethrin disables sodium transport channels on parasitic nerve cell membranes, causing paralysis and death. The 5% cream is applied to dry skin from the neck down, with a repeat application 1 week later.
73
What are the contraindications for using lindane in treating scabies or lice?
Lindane should not be used in patients with seizure disorders, children weighing less than 50 kg, or those with acutely inflamed or raw skin due to risks of CNS toxicity, seizures, and aplastic anemia.
74
What is the role of glycopyrrolate in treating hyperhidrosis, and how does it compare to botulinum toxin type-A?
Glycopyrrolate is an anticholinergic agent that inhibits cholinergic transmission. A 2% glycopyrrolate spray applied twice daily to the axillae has similar efficacy to a single session of botulinum toxin type-A injection at 6 weeks.
75
What is the mechanism of action of Ivermectin and what conditions can it treat?
Ivermectin acts by binding to glutamate-gated and aminobutyric acid-gated chloride ion channels of parasite nerve and muscle cells, leading to increased permeability of chloride ions, paralysis, and death. It can treat scabies, head lice, and rosacea.
76
What are the safety considerations for using Lindane in pediatric patients?
Lindane should be avoided in patients with seizure disorders, children weighing less than 50 kg, and those with acutely inflamed or raw skin due to its potential side effects, including CNS toxicity, seizures, and aplastic anemia.
77
How does the efficacy of Spinosad compare to Permethrin in treating head lice?
Spinosad 0.9% cream has been found to be superior to 1% permethrin cream in the treatment of head lice, being both pediculicidal and ovicidal with a 10-minute application.
78
What are the recommended applications for Aluminum Compounds in treating hyperhidrosis?
Aluminum compounds are typically applied as a first-line therapy in 15% to 20% solutions in the axilla and up to 30% on the palms and soles, applied topically for 1 week at night, and can be used every 1 to 3 weeks as maintenance therapy after control is achieved.
79
What precautions should be taken when using Pyrethrins for lice treatment?
Pyrethrins should be avoided in individuals sensitive to chrysanthemums or ragweed, and the aerosol spray should not be prescribed to patients with a history of asthma due to its neurotoxic effects.
80
What is the pregnancy category of Crotamiton and what is its primary use?
Crotamiton is classified as a Pregnancy category C drug and is primarily used in the treatment of scabies, pediculosis capitis, and occasionally pruritus.
81
What is the role of Glycopyrrolate in the treatment of hyperhidrosis?
Glycopyrrolate is an anticholinergic agent that blocks muscarinic receptors and inhibits cholinergic transmission, used as a systemic therapy and increasingly as a topical treatment for hyperhidrosis, particularly in the face and axillae.
82
What are the side effects associated with the use of Malathion for lice treatment?
Malathion can cause skin irritation and is an organophosphate insecticide that acts by irreversibly binding to acetylcholinesterase, which may lead to systemic toxicity if not used properly.
83
How does the application of 5% Permethrin cream compare to oral Ivermectin in treating scabies?
The application of 5% Permethrin cream twice (1 week apart) was found to be superior to a single dose of oral Ivermectin in treating scabies patients.
84
What is the recommended application method for topical Ivermectin in treating rosacea?
For rosacea, Ivermectin 1% cream should be applied, showing superior efficacy compared to twice-daily metronidazole 0.75% cream in treating inflammatory lesions in patients with moderate to severe papulopustular rosacea.
85
What is the mechanism of action of iontophoresis in treating hyperhidrosis?
Iontophoresis uses electric current to transport ions through the skin, although the exact mechanism by which it decreases sweating is not fully understood. It is typically applied to a hyperhidrotic area covered with lukewarm tap water, with electrodes delivering a direct current.
86
What are the potential adverse effects of iontophoresis?
Adverse effects of iontophoresis may include irritation, hyperesthesia, and blisters.
87
What is doxepin and how does it function as an antipruritic agent?
Doxepin is a tricyclic antidepressant that acts as a potent antagonist of histamine H1 and H2 receptors. Its antipruritic effects may also be due to modulation of adrenergic, muscarinic, and serotonergic receptors.
88
What is the role of menthol in treating itch?
Menthol acts as a counterirritant by inducing a cool sensation through transient receptor potential melastatin 8 (TRPM8) receptors in the skin, which helps to overwhelm the sensation of itch.
89
What are the uses and concentrations of hydroquinone in dermatological treatments?
Hydroquinone is usually used in concentrations of 2% to 5% to decrease pigmentation by inhibiting tyrosinase, blocking the conversion of dopa to melanin. It may also inhibit DNA and RNA synthesis, degrading melanosomes and destroying melanocytes.
90
What is the significance of silver nitrate in dermatological treatments?
Silver nitrate in 0.5% aqueous solution is used as an astringent and antimicrobial agent for treating infected eczema, gravitational ulcers, and other weeping or infected skin lesions. It is bacteriostatic at low concentrations and bactericidal at higher concentrations.
91
What are the side effects associated with the use of hydroquinone?
Side effects of hydroquinone include irritant dermatitis, contact dermatitis, postinflammatory pigmentation, and cutaneous ochronosis.
92
What is the mechanism of action of tretinoin in treating melasma?
Tretinoin works by inhibiting the transcription of tyrosinase, stimulating keratinocyte turnover, and decreasing melanosome transfer, which leads to decreased pigmentation.
93
What is the clinical application of potassium permanganate?
Potassium permanganate is used as an oxidizing agent, astringent, antiseptic, and antifungal. It can be used to clean or deodorize wounds and as a wet compress to reduce weeping.
94
What is azelaic acid and its role in dermatology?
Azelaic acid is a dicarboxylic acid derived from Pityrosporum ovale, functioning as a weak, competitive, reversible inhibitor of tyrosinase, which is relevant in treating hyperpigmentation disorders.
95
How does iontophoresis work in treating hyperhidrosis, and what are its potential adverse effects?
Iontophoresis uses electric current to transport ions through the skin, reducing sweating. Adverse effects include irritation, hyperesthesia, and blisters.
96
A patient with uremic pruritus is prescribed pramoxine hydrochloride. What is its mechanism of action, and how quickly does it work?
Pramoxine hydrochloride inhibits nerve impulse conduction by altering cell membrane permeability to ions. Its onset of action is 2 to 5 minutes.
97
What are the clinical uses of potassium permanganate, and what precautions should be taken during its application?
Potassium permanganate is used to clean or deodorize wounds and reduce weeping. Precautions include avoiding permanent staining of clothing and ceramics and removing temporary skin staining with oxalic acid or sodium thiosulfate.
98
A patient with melasma is prescribed a combination therapy including hydroquinone. What is the mechanism of action of hydroquinone?
Hydroquinone decreases pigmentation by inhibiting tyrosinase, blocking the conversion of dopa to melanin, and possibly degrading melanosomes and destroying melanocytes.
99
What are the potential side effects of tretinoin when used to treat melasma?
Side effects of tretinoin include erythema, desquamation, and postinflammatory hyperpigmentation.
100
What are the potential adverse effects of using phenol as an antipruritic agent?
Phenol can cause systemic absorption and should be avoided in pregnant women and infants. In higher concentrations, it is caustic and used for deep chemical peels.
101
What is the mechanism of action of iontophoresis in treating hyperhidrosis?
Iontophoresis uses electric current to transport ions through the skin, although the exact mechanism by which it decreases sweating is not fully understood. It is most effective on palmar and plantar surfaces.
102
How does doxepin function as an antipruritic agent?
Doxepin is a tricyclic antidepressant that acts as a potent antagonist of histamine H1 and H2 receptors, and its antipruritic effects may also involve modulation of adrenergic, muscarinic, and serotonergic receptors.
103
What is the mechanism by which iontophoresis decreases sweating?
The mechanism by which it decreases sweating is not fully understood. It is most effective on palmar and plantar surfaces.
104
What is the recommended concentration range for phenol when used as an antipruritic agent?
Phenol is used in low concentrations of 0.5% to 2% as an antipruritic agent due to its anesthetic effect.
105
What is the primary use of aluminum acetate in dermatological treatments?
Aluminum acetate is used as an effective astringent and germicidal agent, often in the form of wet dressings, compresses, or soaks for various skin conditions.
106
What are the clinical applications of potassium permanganate?
Potassium permanganate is used as an oxidizing agent, astringent, antiseptic, and antifungal, and can be used to clean or deodorize wounds, as well as in medicated baths.
107
What is the significance of silver nitrate in treating skin lesions?
Silver nitrate is used as an astringent and antimicrobial agent in the treatment of infected eczema, gravitational ulcers, and other weeping skin lesions caused by bacteria.
108
What are the side effects associated with hydroquinone use?
Side effects of hydroquinone may include irritant dermatitis, contact dermatitis, postinflammatory pigmentation, and cutaneous ochronosis.
109
What is the mechanism of action of tretinoin in treating melasma?
Tretinoin inhibits transcription of tyrosinase, stimulates keratinocyte turnover, and decreases melanosome transfer, leading to decreased pigmentation.
110
How does azelaic acid function in skin treatment?
Azelaic acid is a weak, competitive, reversible inhibitor of tyrosinase, which helps in reducing pigmentation.
111
What is the onset of action for pramoxine hydrochloride when used as an antipruritic agent?
The onset of action for pramoxine hydrochloride is typically between 2 to 5 minutes.
112
What is the role of menthol in treating pruritus?
Menthol acts as a counterirritant by inducing a cool sensation that overwhelms the sensation of itch through transient receptor potential melastatin 8 (TRPM8) receptors in the skin.
113
What is the recommended dilution for aluminum acetate when used as a wet dressing?
Aluminum acetate is typically diluted 1:10 to 1:40 (Burow solution) for use as a wet dressing.
114
What are the potential risks of using silver nitrate topically?
Prolonged use of silver nitrate can lead to methemoglobinemia, so methemoglobin levels should be monitored during treatment.
115
What is the combination therapy that has shown efficacy in treating melasma?
Combination therapy consisting of hydroquinone, a retinoid, and a topical steroid has shown efficacy in the treatment of melasma.
116
What is the effect of hydroquinone on melanin production?
Hydroquinone decreases pigmentation by inhibiting tyrosinase, blocking the conversion of dopa to melanin.
117
What is the clinical significance of using potassium permanganate in skin care?
Potassium permanganate can be used to reduce weeping in skin conditions and may cause temporary staining of the skin, which can be removed with specific solutions.
118
What is the primary use of doxepin cream in dermatology?
Doxepin cream is primarily used to treat neuropathic itch, lichen simplex chronicus, and nummular eczema.
119
What are the contraindications for using phenol?
Phenol should be avoided in pregnant women and infants due to its percutaneous absorption and potential toxicity at higher concentrations.
120
What is the effect of tretinoin on keratinocytes?
Tretinoin stimulates keratinocyte turnover, which helps in reducing pigmentation and treating conditions like melasma.
121
What is the recommended concentration of hydroquinone for treating melasma?
Hydroquinone is usually used in concentrations of 2% to 5% for treating melasma.
122
What is the role of pramoxine hydrochloride in managing pruritus?
Pramoxine hydrochloride is effective in cases of mild to moderate pruritus by inhibiting conduction of nerve impulses.
123
What is the significance of using a combination of hydroquinone and retinoids?
The combination enhances the efficacy of treatment for melasma by addressing multiple pathways involved in pigmentation.
124
What is the effect of menthol on TRPM8 receptors?
Menthol activates TRPM8 receptors, inducing a cool sensation that helps alleviate the sensation of itch.
125
What is the clinical application of azelaic acid in dermatology?
Azelaic acid is used to treat conditions related to hyperpigmentation and is effective in reducing melanin production.
126
What is the primary action of aluminum salts in dermatological treatments?
Aluminum salts act as astringents and germicidal agents, helping to manage various skin conditions.
127
What is the effect of potassium permanganate on skin lesions?
Potassium permanganate can clean and deodorize wounds, and is effective in reducing weeping from skin lesions.
128
What is the mechanism of action of doxepin in treating pruritus?
Doxepin's mechanism involves antagonism of histamine receptors and modulation of other neurotransmitter receptors, providing antipruritic effects.
129
What are the potential side effects of using tretinoin?
Side effects of tretinoin may include erythema, desquamation, and postinflammatory hyperpigmentation.
130
What is the significance of monitoring methemoglobin levels when using silver nitrate?
Monitoring methemoglobin levels is important due to the risk of methemoglobinemia associated with prolonged topical use of silver nitrate.
131
What is the effect of hydroquinone on DNA and RNA synthesis?
Hydroquinone may inhibit DNA and RNA synthesis, contributing to its efficacy in treating hyperpigmentation.
132
What is the primary use of monobenzyl ether of hydroquinone and what are its side effects?
Monobenzyl ether of hydroquinone is primarily used to depigment skin in individuals with widespread vitiligo. Its side effects include burning, itching, and erythema.
133
How do alpha-hydroxy acids function in the treatment of hyperkeratosis?
Alpha-hydroxy acids (such as lactic acid, glycolic acid, citric acid, glucuronic acid, and pyruvic acid) reduce the thickness of the hyperkeratotic stratum corneum by solubilizing protein components of desmosomes and activating hydrolytic enzymes, which leads to keratolysis and increased moisture content in the stratum corneum.
134
What is the role of propylene glycol in topical treatments?
Propylene glycol acts as a humectant, occlusive, and keratolytic agent. It enhances the penetration of other medications and is used in combination with lactic acid to treat conditions like lamellar ichthyosis and other hyperkeratotic diseases.
135
What are the uses and effects of salicylic acid in dermatological treatments?
Salicylic acid is used to treat warts, psoriasis, and acne. At concentrations of 3% to 6%, it causes shedding of scales by softening the stratum corneum. Concentrations higher than 6% can be destructive to tissue, but sensitization is rare.
136
What is calcipotriene and how is it applied in treatment?
Calcipotriene is a vitamin D analog that inhibits epidermal proliferation and induces differentiation. It is applied initially twice daily, with maximal improvement expected within 6 to 8 weeks. It may cause cutaneous irritation in some patients.
137
What is cantharidin and what is its clinical application?
Cantharidin is a naturally occurring terpenoid secreted by blister beetles, used clinically to treat warts and molluscum contagiosum by causing acantholysis and blistering of the skin.
138
What is the mechanism of action of diphenylcyclopropenone (DPCP) in treating viral warts?
DPCP is a potent contact allergen that induces an immune response by altering cytokine levels and causing nonspecific inflammation, leading to wart regression. It is recommended to avoid DPCP in children under 12 years of age, although it can be used in younger children with alopecia areata.
139
What are the side effects associated with squaric acid dibutyl ester in treatment?
Squaric acid dibutyl ester can cause eczematous reactions, blistering, and swelling of regional lymph nodes as side effects when used in the treatment of warts and alopecia areata.
140
Why is formaldehyde not commonly used in dermatological treatments?
Formaldehyde is not commonly used due to its potential to cause anhidrosis, desiccation, and hypersensitivity. It can also lead to hardening and fissuring of the skin, and sensitization is problematic for individuals with eczema or allergies.
141
What is the mechanism of action of glutaraldehyde in treating warts?
Glutaraldehyde is viricidal and combines chemically with keratin-producing polymers that harden the wart surface, facilitating paring.
142
What are the common uses of imiquimod and its side effects?
Imiquimod is used to treat genital warts, actinic keratoses, and superficial basal cell carcinoma. Common side effects include local skin irritation and systemic reactions such as fever and fatigue. It is classified as a pregnancy category C drug.
143
How are monochloroacetic, dichloroacetic, and trichloroacetic acids used in wart treatment?
These acids are effective in managing warts at concentrations of 50% to 90%. Trichloroacetic acid is used at lower concentrations (10% to 35%) for facial peels, while monochloroacetic acid is commonly used on plantar warts under salicylic acid plaster occlusion. Applications need to be repeated at 1- to 2-week intervals until complete resolution.
144
What is the role of podofilox in treating warts?
Podofilox, the active ingredient of podophyllin, is used to treat warts and molluscum contagiosum. It should not be used during pregnancy unless the potential benefit justifies the risk to the fetus.
145
What is the effectiveness of salicylic acid in wart treatment?
Salicylic acid is effective in treating warts due to its role in keratolysis and local irritation of the skin where the virus is present. It is the most established agent regarding efficacy and safety in the treatment of viral warts.
146
What is the application regimen for sinecatechins ointment in treating external genital warts?
A 15% sinecatechins ointment is applied 3 times daily until all warts are cleared, for up to a maximum of 16 weeks. Its mechanism of action may involve immunostimulatory, antiproliferative, antiangiogenic, and antitumor properties of catechins.
147
What is the mechanism of action of cantharidin in treating warts, and what is its pregnancy category?
Cantharidin causes acantholysis and blistering of the skin. It is a pregnancy category C drug.
148
A patient with alopecia areata is prescribed diphenylcyclopropenone (DPCP). What are its proposed mechanisms of action?
DPCP may alter cytokine levels, induce nonspecific inflammation causing wart regression, or bind to wart protein to induce a specific immune response.
149
What are the proposed mechanisms of action of diphenylcyclopropenone (DPCP) in treating alopecia areata?
DPCP may alter cytokine levels, induce nonspecific inflammation causing wart regression, or bind to wart protein to induce a specific immune response.
150
What are the common side effects of squaric acid dibutyl ester, and how does it function in treating warts?
Squaric acid dibutyl ester functions by eliciting an inflammatory response. Common side effects include eczematous reactions, blistering, and swelling of regional lymph nodes.
151
Why is dinitrochlorobenzene not commonly used despite its effectiveness in treating warts?
Dinitrochlorobenzene is not commonly used because it was found to be mutagenic by the Ames test and genotoxic through the exchange of sister chromatids in human fibroblasts.
152
What precautions should be taken when using formaldehyde as a wart treatment?
Precautions include protecting normal surrounding skin with petrolatum or zinc paste and avoiding use in individuals with eczema or allergies due to sensitization risks.
153
What is the mechanism of action of imiquimod, and for which conditions is it commonly used?
Imiquimod stimulates the innate immune system through toll-like receptor 7. It is used to treat genital warts, actinic keratoses, and superficial basal cell carcinoma.
154
What is the application protocol for monochloroacetic acid in treating plantar warts?
Monochloroacetic acid is applied under salicylic acid plaster occlusion and repeated at 1- to 2-week intervals until complete resolution.
155
What is the active ingredient in podophyllin, and what are the pregnancy-related precautions for its use?
The active ingredient is podophyllotoxin. It should not be used during pregnancy unless the potential benefit justifies the potential risk to the fetus.
156
How does sinecatechins ointment work in treating external genital warts, and what is its application protocol?
Sinecatechins ointment has immunostimulatory, antiproliferative, antiangiogenic, and antitumor properties. It is applied three times daily until all warts are cleared, for up to a maximum of 16 weeks.
157
What is the mechanism of action of glutaraldehyde in treating warts?
Glutaraldehyde is viricidal and combines chemically with keratin-producing polymers, which harden the wart surface, facilitating paring.
158
What are the common side effects associated with imiquimod treatment?
Common side effects include local skin irritation, and systemic reactions are uncommon but can include symptoms such as fever and fatigue.
159
How is monochloroacetic acid typically used in the treatment of warts?
Monochloroacetic acid is most commonly used on plantar warts under salicylic acid plaster occlusion, with applications repeated at 1- to 2-week intervals until complete resolution.
160
What is the primary use of podofilox in dermatological treatments?
Podofilox is used to treat warts and molluscum contagiosum, but should not be used during pregnancy unless the potential benefit justifies the risk to the fetus.
161
What is the effectiveness of salicylic acid in treating warts attributed to?
The effectiveness of salicylic acid in treating warts is thought to be related to keratolysis and local irritation of the skin where the virus is present.
162
What is the recommended application frequency for sinecatechins ointment in the treatment of external genital warts?
Sinecatechins ointment is applied 3 times daily until all warts are cleared, for up to a maximum of 16 weeks.
163
What pregnancy category is imiquimod classified under?
Imiquimod is classified as a pregnancy category C drug.
164
What are the concentrations of trichloroacetic acid used for facial peels?
Trichloroacetic acid is commonly used at lower concentrations of 10% to 35% for facial peels.
165
What is the clinical significance of using salicylic acid in wart treatment?
Salicylic acid is the most established agent in terms of consistency of data regarding efficacy and safety in the treatment of viral warts.
166
What properties of catechins are believed to contribute to the efficacy of sinecatechins ointment?
The efficacy of sinecatechins ointment may be related to the immunostimulatory, antiproliferative, antiangiogenic, and antitumor properties of catechins.
167
What is the mechanism of action for Ivermectin as a topical antiparasitic agent?
Ivermectin binds to glutamate-gated chloride channels, leading to paralysis of the parasites.
168
What are the major side effects or contraindications associated with the use of Lindane?
Lindane may cause seizures, muscle spasms, and skin irritation; it is contraindicated in patients with a history of seizures and in young children.
169
What is the mechanism of action for Diphenhydramine as a topical antipruritic?
Diphenhydramine acts as an antihistamine, providing local anesthesia and histamine antagonism.
170
What precautions should be taken when using Doxepin as a topical antipruritic?
Doxepin can cause potential contact sensitization and significant systemic absorption, which may result in drowsiness; it is contraindicated in patients taking monoamine oxidase inhibitors.
171
What are the indications for using Salicylic acid as a topical keratolytic agent?
Salicylic acid is indicated for the treatment of hyperkeratosis, scaling, ichthyosis, and psoriasis.
172
What is the recommended dosage for Urea when used as a topical keratolytic agent?
Urea should be applied twice daily to 10% to 40% creams and lotions.
173
What is the mechanism of action for Menthol in topical applications?
Menthol acts as a counter irritant, providing a cooling sensation on the skin.
174
What is the recommended dosage for α-Hydroxy acids when used as a peeling agent?
α-Hydroxy acids are used at a concentration of 2% to 20% as nonpeeling agents and >20% as peeling agents.
175
What are the potential side effects of using Phenol as a topical anesthetic?
Phenol can cause local anesthesia and may lead to skin irritation or allergic reactions in some patients.
