Chapter 42

1. Chapter 42 Agents Used in the Treatment of Skin Conditions

2. The Skin • The largest organ • Several functions • Protective barrier—microbials and trauma • Senses temperature changes • Secretes wastes through sweat glands • Stores fat • Synthesizes vitamin D • Provides a site for drug absorption

3. Epidermis • Outer layer • Thickness is variable • Basal layer is where new cells are formed • Old cells migrate to surface

4. Epidermis • Prickle layer • Protein projections connect adjacent cells • Cells become flat and press together • Compressed cells become the keratin layer • Keratin layer is the protective barrier

5. Dermis • Thicker than the epidermis • Provides support and nourishment for the epidermis • Rich supply of blood vessels, nerves, sweat glands, and hair follicles

6. Structures of The Skin • Hair and nail tissue • Eccrine and apocrine sweat glands • Sweat contains water and waste products • Eccrine glands are located throughout the body

7. Skin structures • Apocrine glands are associated with a hair follicle – mainly in axillary and pubic areas • Emotional stimuli causes excretion of electrolyte solution

8. Skin Structures • Sebaceous glands – connected to hair follicles • Large numbers on head and face • At puberty, secretes oily mixture

9. Emollients Keratolytics Local anesthetic agents Local antipruritic agents Antibacterial agents Drug Classification of Dermatological Agents

10. Emollients • Dry skin causes discomfort, itching, cracking, and predisposition to skin disorders • Treatment is use of emollients • Oily in nature: some skin lotions are emollients • Prevents loss of additional skin moisture

11. Emollients • Forms occlusive barrier • Most contain waxes, fats, and/or oils • Most effective when applied after shower or bath • Do not use on skin lesions that are moist or exudative

12. Keratolytics • Some disorders cause a thickening of the keratin layer • Skin becomes brittle and easily cracked • Causes itching and discomfort • Salicylic acid, lactic acid, and acetic acid

13. Keratolytics • Applied after area has been bathed or soaked • More effective if covered with occlusive dressing • Kept on skin overnight; removed in morning • Repeated applications are effective

14. Local Anesthetics and Antipruritic Agents • Inhibits conduction of nerve impulses from sensory nerves • Reduces pain and itching • Used topically for insect bites, burns, and plant allergies

15. Local Anesthetics and Antipruritic Agents • Poorly absorbed through intact skin • Enhanced through damaged skin • Local or systemic adverse effects • Allergic reaction (locally or systemically)

16. Local Anesthetics and Antipruritic Agents • Topical anesthetics should only be used when absolutely necessary • Avoid in patients with previous hypersensitivity reactions • Avoid in severely traumatized skin

17. Local Anesthetics and Antipruritic Agents • ‘caine’ types • Ointment, cream, spray, liquid or gel forms • Some antipruritic products contain antihistamines • Can be associated with development of local irritation and hypersensitivity reactions

18. Antibacterial Agents • Prevents infection • Treats superficial infections • Treat acne vulgaris • Associated with development of hypersensitivity

19. Antibacterial Agents • Topical antibiotic agents are not usually ones that are used systemically • Combination therapy is popular • Caution when applying to large areas • Systemic effects may be possible

20. Drug Classification of Dermatological Agents • Antiviral agents • Antifungal agents • Anti-inflammatory agents • Antiparasiticidal agents

21. Antifungal Agents • Treats two types of fungal infections • Dermatophyte organisms • Yeastlike organisms

22. Dermatophyte Infections • Caused by tinea or others • Most common is ringworm type • Circular pattern

23. Dermatophyte infections • Scalp, nails, and/or skin • Always superficial • May be known as ‘athlete’s foot’ or ‘jock itch’

24. Dermatophyte Infections • Can live only on dead keratin tissue • Affected area must be replaced with fungus-free tissue • Agents must be continued long-term

25. Dermatophyte Infections • Relapses common • Ointment, cream, aerosol, lotion, and powder forms • If burning or irritation develops, discontinue use

26. Dermatophyte Infections • Oral treatment may be effective • Deposits in newly formed skin cells • When new cells reach keratin layer, they are resistant to fungus • Best absorbed with or after a fatty meal • Monitor for hypersensitivity

27. Yeastlike Infections • Involves warm, moist areas and mucous membranes • Moisture promotes yeast growth • Ventilation of area is important • Treatment should be continued for 1 week following lesion disappearance

28. Antiviral Agents • Most difficult to treat • Herpes simplex 1 and 2 • Topical agents - cannot completely eradicate • Decreases healing time and pain

29. Antiviral agents • Topical, oral, or parenteral forms • Topical form can cause burning, stinging, itching, or rash • Caution in patients with renal impairment • Monitor for hypersensitivity

30. Anti-Inflammatory Agents • Topically applied corticosteroids • Alleviates inflammatory symptoms • Irritation or allergic disorders • Useful in controlling psoriasis • Interferes with normal immunological responses • Reduces redness, itching, and edema • Slows rate of skin cell production

31. Anti-Inflammatory Agents • Effectiveness depends on potency of drug, vehicle used, skin thickness and integrity, and presence of moisture • Damaged skin may increase amount of drug absorbed systemically

32. Anti-Inflammatory Agents • Increases systemic side effects • Occlusive dressings increase absorption • Potent agents must be used with caution on thin skin • Do not use in the presence of fungal infection

33. Antiparasitic Agents • Parasites live on outer surfaces • Lice and scabies • Lice is transmitted person to person • Lives on head, body, or pubic area • Scabies is a mite; burrows under the skin and lays eggs • Drug of choice is lindane • Do not use in children under 2 • Can cause seizures if applied to open skin • CNS toxicity

34. Additional Dermatologic Agents • Debriding agents • Antineoplastic agents • Burn treatment agents • Eczema agents • Psoriasis agents • Topical hair agents • Agents for diabetic foot ulcer

35. Diabetic Foot Ulcers • Leading cause of amputations • Microvascular and neurological changes due to long-term elevated blood sugar levels • Increases migration of cells responsible for wound healing to site of ulcer

36. Diabetic Foot Ulcers • Needs adequate blood supply • Gel form helpful for protecting healing wounds • Long-term therapy required – Regranex promotes healing

37. Antineoplastic Agents • Destroys cells that grow rapidly • Topical treatment of solar or actinic keratosis • Premalignant skin lesions • Develops in fair skinned people exposed to heavy sunlight • Also used to treat basal cell carcinomas

38. Antineoplastic Agents • Use nonmetallic applicators • Protect skin with rubber gloves • Wash hands immediately • Avoid contact with eyes, nose, or mouth • Avoid exposure to sunlight

39. Agents Used to Treat Burns • Treatment aimed at preventing infection • Important to prevent toxic absorption into systemic circulation • Blood supply is impaired • Topical products may be only way to prevent infection

40. Agents used to treat burns • Occludes site to prevent contamination • Applied to burn after cleaning and debriding • Therapy continued until healing well or ready for grafts • Monitor for hypersensitivity and adverse effects

41. Minoxidil • Systemically used as an antihypertensive • Topically promotes hair growth • Dilates local blood vessels • Long-term use • Caution with patients with heart disease • May cause tachycardia, fluid retention, and/or weight gain • Systemic effects more likely if applied to broken skin

42. Topical Debriding Agents • Purpose • Remove dead skin • Promote healing

43. Topical Debriding Agents • Made of enzymes • General action • Digest dead necrotic tissue • Specific action • Made of enzymes that digest: • Collagen: collagenase (Santyl) • Fibrin in a blood clot: fibrinolysin (Elase)

44. Debriding Agents • Promotes removal of dead tissue • Removal of dead tissue enhances formation of new tissue • Wound healing occurs more quickly • Second- and third-degree burns and decubitus ulcers • Enzymes selectively digest dead tissue • Specific in action

45. Eczema • S & S of acute or chronic conditions • Area appears inflamed • Skin may be dry and may include wet or weepy drainage • Definition • Inflammatory skin condition. Symptoms are pustules, redness, vesicles, crusts, skin thickening, and persistent itching and burning.

46. Eczema • Drug agent • Pimecrolimus (Elidel) • Topical immunomodulator • Adverse effects • Site irritation • Headache

47. Agents Used to Treat Eczema • Eczema is a chronic inflammatory disease of the skin • Itching and scaling of the skin • Piecrolimus - short-term and intermittent long-term use - adverse effects include site irritation and headache • Tacrolimus - not a steroid - adverse effect is an increased risk for skin infections

48. Psoriasis • A chronic skin condition • Consists of painful reddened papules that form plaques with distinct borders • Other patches appear as silvery yellow-white scales • Usually located • Elbows, scalp, knees, and genitalia • Amevive (alefacept) • Raptiva (efalizumab)

49. Psoriasis • Drug agent • Alefacept (Amevive) • Immunosuppressant • Stops the activity of T lymphocytes • Given intramuscularly • Adverse effects • Infection

50. Agents Used to Treat Psoriasis • Psoriasis is an autoimmune chronic skin disorder • Plaques on the skin – itching, bleeding, cracking • Alefacept – promotes longer remissions • Efalizumab – stimulates body’s immune response