Dermatology Treatments Quiz

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Questions and Answers

What side effect may occur when applying ovale to affected areas?

Improved skin moisture

Sensitivity reactions in some individuals (correct)

Increased hair growth

Decreased skin elasticity

What is the primary action of zinc pyrithione in treating dandruff?

Decreases scalp sensitivity

Increases epidermal turnover

Inhibits P. ovale (correct)

Promotes hair follicle growth

What is a significant concern associated with the prolonged use of corticosteroids on the scalp?

Decreased effectiveness of other treatments

Increased dandruff severity

High relapse rates upon discontinuation (correct)

Increased scalp moisture

What is the mechanism by which melanizing agents affect the skin?

They stimulate melanocyte proliferation upon photoactivation Signup and view all the answers

What effect does salicylic acid have in the treatment of seborrheic dermatitis?

Enhances penetration of other treatments Signup and view all the answers

Which of the following statements about clindamycin is true?

It is appropriate for use in cases with inflamed papules. Signup and view all the answers

Which of the following best describes the action of azelaic acid?

It reduces the content of free fatty acids in skin surface lipids. Signup and view all the answers

Which of the following is a potential complication of long-term tetracycline use?

Intracranial hypertension after two months of use. Signup and view all the answers

What is the primary function of isotretinoin in acne treatment?

To reduce abnormal keratinization of follicles. Signup and view all the answers

What is the main purpose of topical steroids in acne treatment?

To provide immunosuppressive action. Signup and view all the answers

What is the primary advantage of using Ivermectin for treating scabies?

It is orally administered and shows high effectiveness. Signup and view all the answers

What is a significant drawback of using sulfur 10% ointment for treatment?

Its use can lead to social stigma due to odor. Signup and view all the answers

Which of the following statements about Crotamiton is correct?

It has low systemic toxicity despite skin absorption. Signup and view all the answers

What is the recommended method of application for Dicophane (DDT) when treating scabies?

Applied and washed off after 12–24 hours. Signup and view all the answers

In the context of ectoparasiticides, what describes the application of pediculosis treatments?

To wash off after 24 hours of application. Signup and view all the answers

What is the main advantage of using permethrin as an ectoparasiticidal agent?

It produces high cure rates in scabies and pediculosis. Signup and view all the answers

How does lindane primarily function to kill lice and mites?

By penetrating through the chitinous layer. Signup and view all the answers

What is a significant side effect of using lindane, particularly in children?

Systemic toxicity leading to convulsions. Signup and view all the answers

What is the main reason for the addition of benzyl benzoate to lindane in treatment?

To improve the cure rate and prevent resistance. Signup and view all the answers

How should permethrin be applied for the treatment of scabies?

Applied all over the body except the face and head. Signup and view all the answers

What is a common treatment regimen for head lice using lindane?

Applied for 12–24 hours and rinsed off. Signup and view all the answers

What is a notable characteristic of benzyl benzoate as an ectoparasitic treatment?

It is an oily liquid with a faint aromatic smell. Signup and view all the answers

Which of the following describes a disadvantage of using lindane?

It can induce liver enzyme processes. Signup and view all the answers

Which site has the highest penetration for topical steroids?

Axilla Signup and view all the answers

What is the best vehicle for treating exudative lesions with topical steroids?

Lotions & creams Signup and view all the answers

Which of the following is a characteristic of occlusive dressings for topical steroids?

They enhance absorption by up to 10 times. Signup and view all the answers

For which condition should potent topical steroids be restricted?

Severe inflammatory conditions Signup and view all the answers

What local adverse effect can result from the prolonged use of topical steroids?

Thinning of epidermis Signup and view all the answers

Which ectoparasitic condition is caused by the Sarcoptes scabiei mite?

Scabies Signup and view all the answers

Which measure is essential in preventing reinfection of scabies among family members?

Washing garments and bedding in hot water Signup and view all the answers

Which of the following side effects might occur with the systemic application of topical steroids?

Adrenal pituitary suppression Signup and view all the answers

For which condition is a combination of steroid with antimicrobial most appropriate?

Impetigo Signup and view all the answers

In which of the following conditions is continuous occlusion of lesions not recommended?

Lesions in infants and young children Signup and view all the answers

Which drug is primarily used for mild-to-moderate psoriasis and provides a response within 3 weeks?

Topical corticosteroids Signup and view all the answers

What effect does Calcipotriol have when used in plaque-type psoriasis?

It enhances keratinocyte differentiation. Signup and view all the answers

Which of the following is a potential side effect of Tazarotene?

Skin irritation and peeling Signup and view all the answers

What is the purpose of PUVA therapy in treating psoriasis?

To interfere with DNA synthesis Signup and view all the answers

What action does hydroquinone perform on the skin?

It lightens hyperpigmented patches. Signup and view all the answers

Which ingredient in sunscreens absorbs UVB rays?

Para-aminobenzoic acid Signup and view all the answers

What is a major concern associated with long-term use of tanning products?

Photosensitivity reactions Signup and view all the answers

How does benzoyl peroxide help in treating acne vulgaris?

It liberates oxygen, killing bacteria. Signup and view all the answers

What is a noted effect of retinoic acid in acne treatment?

It prevents comedone formation. Signup and view all the answers

Which agent is known for its potential to cause permanent depigmentation?

Monobenzone Signup and view all the answers

Which of the following substances is classified as a physical sunscreen?

Titanium dioxide Signup and view all the answers

What type of skin reaction can result from the use of coaltar?

Carcinogenicity Signup and view all the answers

Which of the following treatments for acne vulgaris directly modulates keratinization?

Adapalene Signup and view all the answers

Which therapy is specifically reserved for severe and refractory cases of psoriasis?

Systemic corticosteroids Signup and view all the answers

Study Notes

Musculoskeletal and Integumentary System

Dermatologic Pharmacology by Abdurazak Jemal Tura (B.Pharm, MSc in Pharmacology, Assistant Professor)

Drugs Acting on Skin

Variety of drugs applied topically to the skin have localized effects at the site of application.
These drugs act through physical, chemical, and biological attributes.
They are categorized based on their prominent action.

Demulcents

These are inert substances that soothe inflamed/denuded skin by preventing contact with irritants.
They are high molecular weight substances.
Applied as thick colloidal/viscid solutions in water.
Serve as protective agents.
Examples include propylene glycol, glycerin, and methylcellulose.

Emollients

These are oily substances that soothe and soften skin.
Form an occlusive film to prevent evaporation.
Restore elasticity to cracked and dry skin.
Serve as protective agents.
Examples include olive oil, arachis oil, sesame oil, cocoa butter, hard/soft paraffin, liquid paraffin, wool fat, beeswax, and spermaceti.

Adsorbants/Protectives

These are inert insoluble solids that bind to noxious and irritant substances (adsorbing).
Afford physical protection to the skin.
Form a continuous, adherent, and flexible occlusive coating
Examples include magnesium/zinc stearate, calamine, starch, boric acid, polyvinyl polymer, and sucralfate gel.

Astringents

These substances precipitate proteins.
Do not penetrate cells, affecting only the superficial layer.
Toughen the surface, making it mechanically stronger and decreasing exudation.
Reduce secretion from sweat glands, preventing sweat decomposition by bacteria, and reducing body odor.
Examples include tannic acid/tannins, ethanol, and methanol (50-90%).
Also include aluminum, zinc, and zirconium salts.

Irritants

Irritants stimulate sensory nerve endings.
Induce inflammation at the site of application.
Produce cooling or warming sensations, pricking, tingling, hyperesthesia, and numbness.
Counter irritants produce superficial inflammation to reduce deeper inflammation.
Some irritants produce a remote effect, relieving pain and inflammation in deeper organs.

Counterirritants

Massaged to relieve headache, muscular pain, joint pain, pleural/peritoneal pain, and colic.
Volatile oils (essential oils) produce a cooling sensation on skin.
Examples include turpentine oil, clove oil, eucalyptus oil, camphor, menthol, thymol, mustard seeds, capsicum, methyl salicylate, and alcohol.

Caustics & Escharotics

These cause local tissue destruction and sloughing (shedding).
Cause protein precipitation that exudes to form a scar.
Used to remove moles, warts, condyloma, papillomas, and keratotic lesions.
Microbes may be killed during cauterization.
Examples include podophyllum resin, silver nitrate, phenol, trichloroacetic acid, and glacial acetic acid.

Keratolytics

Dissolve intercellular substance in the horny layer of skin.
Cause epidermal cells to swell, soften, and desquamate (peel off).
Used for hyperkeratotic lesions like corns, warts, psoriasis, chronic dermatitis, ringworm, and athlete's foot.
Salicylic acid (10-20% solution in propylene glycol) dissolves corns and is applied under a polyethylene occlusive dressing, causing maceration of skin.
Resorcinol (3-10%) is an antiseptic, antifungal, and local irritant that is used for eczema, seborrheic dermatitis, and ringworm.
Urea (5-20% in cream/ointment) is a humectant (hygroscopic) and water-retaining agent that softens and solubilizes keratin, facilitating removal from hyperkeratinized lesions like ichthyosis and lichen planus.

Antiseborrheics

Seborrheic dermatitis affects sebaceous glands in scalp, face and trunk, characterized by erythematous, scaling lesions, and dandruff.
Yeast, Pityrosporum ovale, is a causal role.
Selenium sulfide (2.5% lotion or shampoo) slows epidermal proliferation and scaling, and is antikeratolytic and fungicidal to P. ovale.
Zinc pyrithione (1% weekly shampoo) reduces epidermal turnover and inhibits P. ovale, reducing dandruff, and often combined with ketoconazole.
Corticosteroids (massaged in scalp as a lotion) are effective in relieving symptoms, including dandruff.
Sulfur, resorcinol, coal tar, and ammoniated mercury are mildly effective and may benefit seborrhea due to their keratolytic and antiseptic properties.
Salicylic acid has a mild effect in seborrhea.

Melanizing Agents

Increase sensitivity to solar radiation and promote repigmentation of vitiliginous skin.
Photoactivation stimulates melanocytes and induces their proliferation.
Psoralens (methoxsalen, trioxsalen) sensitize skin to sunlight, inducing erythema, inflammation, and pigmentation.
Applied topically and orally.

Drugs for Psoriasis

Psoriasis is an immunological disorder with localized or widespread erythematous scaling lesions or plaques.
Epidermal proliferation is attended by dermal inflammation, and periodic flare-ups are common.
Drugs diminish lesions but cannot cure them.
Therapy is prolonged and adjusted to disease severity.
Topical therapy for psoriasis includes emollients, keratolytics, and antifungals for symptomatic relief.
Topical corticosteroids are primary drugs, effective for mild-to-moderate disease.
Systemic corticosteroids or immunosuppressants are reserved for severe and refractory cases.

Calcipotriol

Effective topically in plaque-type psoriasis.
Binds to intracellular vitamin D receptors in epidermal keratinocytes and suppresses proliferation while enhancing differentiation.
Benefit is slow; responding in 4–8 weeks.
Comparable to moderate-potency topical steroids.
Safe and effective alternative to steroids, but expensive.

Tazarotene

Synthetic retinoid as a topical gel (0.05–0.1%).
Prodrug hydrolyzed into tezarotenic acid in skin
Binds to retinoic acid receptors and modifies gene function.
Has antiproliferative and anti-inflammatory action.
Beneficial with topical steroids/calcipotriol in refractory cases.
Skin irritation, burning, and peeling are common but minimized by careful application to plaques only.
Teratogenic.

Coal Tar

Crude preparation that contains phenolic compounds.
Exposure to light exerts phototoxic action on skin.
Induces resolution of psoriatic lesions.
Retards epidermal turnover and applied on psoriatic plaques, often with salicylic acid.
Causes skin irritation, allergies, photosensitivity, and potential carcinogenicity.

Photochemotherapy (PUVA)

Uses psoralen and ultraviolet A light.
Photoactivated psoralen binds to pyrimidine bases.
Interferes with DNA synthesis and epithelial cell turnover.
Used in severely debilitating cases of psoriasis.
Oral methoxsalen followed by UVA exposure on alternate days.
Possible risks include skin cancer, cataracts, and immunological damage.

Demelanizing Agents

Hydroquinone lightens hyperpigmented patches on skin.
Weak hypopigmenting agent.
Inhibits tyrosinase and melanin-forming enzymes.
Decreases melanin formation and increases degradation of melanosomes.
Regular application (2-6% lotion/cream) for months is required for melasma and chloasma of pregnancy.
Causes skin irritation, rashes, and allergies.

Monobenzone

Potent demelanizing agent that destroys melanocytes.
May cause permanent depigmentation.
Full effect takes 4-6 months; treated areas should be protected from sunlight by a sunscreen.
Restricted to patients with widespread vitiligo (5% lotion or 20% ointment, applied 2-3 times daily).

Azelaic Acid

Effective in hyperpigmentary disorders.
Inhibits the melanin-forming enzyme tyrosinase.
Has reversible hypopigmentary action
Used as a 10% or 20% cream.
Causes mild and transient local irritation.

Sunscreens

Substances that protect skin from harmful effects of sunlight exposure.
Chemical sunscreens absorb UV rays, converting them into heat released from the skin.
Efficacy is quantified by the sun protection factor (SPF), the ratio of UVB radiation dose to produce minimal erythema on protected skin compared to unprotected skin.
Para-aminobenzoic acid (PABA) is a glyceryl mono amino benzoate that absorbs UVB (290-320nm). Used in 5% solution in alcohol/propylene glycol or 10% cream.
Benzophenones (oxybenzone 2-6%) block UVA (320-400nm) and highly protective, though higher concentrations prevent tanning.
Cinnamates (octyl methoxy cinnamate) are included in sunscreens.
Physical sunscreens are opaque substances that scatter UV and visible light; include petroleum jelly, titanium dioxide, zinc oxide, and calamine.
Prevent penetration into the skin.

Drugs for Acne vulgaris

Common skin disease in adolescent boys and girls.
Androgenic stimulation of sebaceous follicles leads to excess sebum production.
This sebum gets colonized by bacteria and yeast.
Bacterial lipases produce free fatty acids (FFAs) that irritate follicular ducts, causing retention of secretions and hyperkeratosis which rupture into the dermis leading to inflammation and pustules.

Topical Therapy

Benzoyl peroxide liberates oxygen (in presence of water) killing bacteria, anaerobic/microaerophilic types, specifically against Propionibacterium acnes.
Is a keratolytic and comedolytic agent that induces mild desquamation, shedding comedone caps causing reduction in irritant fatty acids in sebum.
Retinoic acid is a potent comedolytic agent that promotes lysis of keratinocytes.
Prevents horny cells from clumping, thus preventing comedones (horny impactions in follicles) formation.
Response to retinoic acid treatment is delayed, in 6-10 weeks.
Potentially skin irritant.
Adapalene directly binds to the retinoic acid receptor, modulating keratinization and differentiation of follicular epithelial cells.
Has anti-inflammatory action and suppresses comedone formation.
Less irritating than tretinoin.
Topical antibiotics (clindamycin, erythromycin, tetracyclines) are less effective against P. acnes than benzoyl peroxide, appropriate for cases with inflamed papules but do not irritate skin, and can cause sensitization if applied inappropriately.
Azelaic acid inhibits aerobic and anaerobic microorganisms, including P. acnes.
Reduces cutaneous bacterial density, free fatty acid content of skin surface lipids, and keratinocyte proliferation.

Systemic Therapy

Antibiotics (tetracycline, minocycline, erythromycin) are indicated in severe cases of acne with cysts and pustules.
Maintenance doses may be continued for months but long-term use can have complications like a risk of intracranial hypertension if using tetracyclines for more than 2 months.

Isotretinoin

Orally administered retinoid reducing sebum and skin bacteria.
Corrects abnormal keratinization of follicles.
A 20-week course is typically prescribed to reduce cystic acne, bring about remission in most cases.
Relapses can occur after variable intervals, and is highly teratogenic.

Topical Steroids

Used for a variety of dermatological conditions (anti-inflammatory, immunosuppressive, and antiproliferative for scaling lesions).
Examples include beclomethasone dipropionate, betamethasone benzoate, betamethasone valerate, clobetasol propionate, and dexamethasone sod. phosphate.

General Guidelines for Topical Steroids

Penetration varies at different sites.
High in axilla, groin, face, scalp.
Medium is limbs and trunk.
Low in palm, sole, elbow, knee.
Absorption depends on the nature of the lesion (high in atopic and exfoliative dermatitis and low in hyperkeratinized/plaque forming lesions).
Vehicle choice is important (lotions/creams better for exudative lesions, allowing evaporation and cooling. Sprays/gels are used in hairy regions. Ointments for chronic and scaly conditions provide an occlusive film).
Occlusive dressings enhance absorption, particularly in chronic, hypertrophied lesions; this is done intermittently (no more than 12 hrs at a time).
Overall, absorption is higher in infants & children, thus requiring milder agents.
Routine use of potent steroids should be avoided except when restricted to severe inflammatory conditions, unresponsive eczema or psoriasis, or short-term or intermittent use to prevent adverse effects.
Sudden discontinuation is also to be avoided.
Combinations with antimicrobials are justified for infected dermatoses (impetigo, furunculosis, secondary infections, napkin rash, otitis externa, and intertriginous eruptions). Local adverse effects are related to potency & duration.

Ectoparasiticides

Drugs used to kill parasites that live on the body surface (lice = Pediculus sp. = wingless insects & mites = Sarcoptes/Acarus scabiei = arachnids). Used for minute arthropods infesting human skin and hair.

Scabies

Highly contagious mite species.
Mites burrow through epidermis; producing an intensive itch.
Lay eggs in the lesions forming papules that itch.
Finger webs and the areas around forearms, trunk, genitals and lower legs are the common entry points, thus spreading to other members that are in concurrent contact, including all forms of clothes and bed linens.
Wash clothes and bed linen in hot water and sun to prevent cross infection & reinfection.

Pediculosis

Lice (Head lice = P. Capitis, Body lice= P. Corporis or Pubic lice = P. Pubis) cause itching and transmit typhus and relapsing fever by sucking blood.
Eggs are attached to hair/clothing by a chitin-like cement that sticks to hair and clothing.

Permethrin

Broad-spectrum and potent pyrethroid insecticide.
Effective and convenient for scabies & lice.
Neurological paralysis by delaying depolarization.
Low toxicity in humans.
Persists on the skin for days.
Minimal systemic absorption; 100% cure for scabies and pediculosis.

Lindane (Gamma benzene hexachloride, BHC)

Broad-spectrum insecticide.
Kills lice & mites by penetrating chitinous structures.
Cure rate ranges from 67-92% for headlice and 84-92% for scabies; reduced efficacy compared to permethrin.
Lice and mites can develop resistance to lindane.
Benzyl benzoate addition reduces resistance improving the cure rate to nearly 100%.

Dicophane (DDT)

Popular insecticide used in dust or water suspension form.
Poorly absorbed through skin.
Neurotoxin to arthropods, though can cause allergic rashes and muscle weakness or tremor when applied with oily substances.
Inducing microsomal enzymes, combined with benzyl benzoate produces a more effective combination.

Ivermectin

Highly effective insecticidal oral drug for scabies and pediculosis.
Single dose of 0.2 mg/kg (12 mg for adults), often cures 91-100% of patients with scabies.
Can effectively treat patients with head/body lice.
Restricted to non-pregnant or lactating women, or children under 5 years.
Has reduced efficacy compared to topical agents.

Crotamiton

Effective scabicide, pediculocide & anti-pruritic agent.
Lower cure rates (60-88%).
Extended 5-day application for children.
Less prone to cause skin irritation.
Low systemic toxicity.

Sulfur (10% ointment)

Scabicide, pediculocide, fungicide, keratolytic agent.
Dissolves itch mite cuticle and kills it.
Applied after warm scrubbing bath to open burrows.
Massaged over the entire body (below the neck) for 3 days, followed by a soap bath on the fourth day.

Benzyl Benzoate

Oily liquid with mild aromatic smell.
Popular for scabies treatment.
Emulsion applied after a cleansing bath.
Second coat is applied the next day, and washed after 24 hrs.
Treatment does not interfere with routine activities
Achieved cure rates of 76-100% in scabies.
Neurological symptoms can occur in children. Skin irritation & contact dermatitis are possible side effects.

General Guidelines for Pediculosis Treatment

Applied on scalp & hair, not to eyes, leave for 12-24 hours and wash off.

General Considerations for Topical Steroid Treatment of lesions

Potent steroids should not be used on a daily basis and should be restricted for severe inflammatory conditions, unresponsive eczema, or psoriasis, and should be used short term or intermittently.
Sudden discontinuation should be avoided, and applications of more than twice a day is not advisable since it doesn't offer additional benefit in the outcome. The twice-daily application is satisfactory to achieve the desired outcome.

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Description

Test your knowledge on various dermatology treatments including the use of corticosteroids, zinc pyrithione, and isotretinoin. This quiz covers mechanisms, side effects, and advantages of different topical agents. Explore the complexities of treating conditions like dandruff, acne, and scabies.