1. Fundamentals of Pharmacology for Veterinary Technicians Chapter 17 Drugs for Skin Conditions © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

2. Basic Anatomy and Physiology • The skin is made up of three layers: • Epidermis (the most superficial layer that contains cells, but not blood vessels) • Dermis (the middle layer that is composed of blood and lymph vessels, nerve fibers, and the accessory organs of skin such as glands and hair follicles) • Subcutaneous (the deepest layer that is composed of connective tissue) © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

3. Basic Anatomy and Physiology © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

4. Drugs Used inTreating Skin Disorders • Topical treatments consist of agents applied to a surface; they affect the area to which they are applied • Topical antibiotics and antifungals are covered in Table 17-1 • Systemic treatments consist of drugs given systemically that affect many areas of the body • Covered in a variety of previous chapters © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

5. Drugs Used inTreating Pruritus • Topical antipruritics provide moderate relief of itching (may be used with systemic medication) • Topical nonsteroidal antipruritics • Local anesthetics such as lidocaine, tetracaine, benzocaine, and pramoxine • Soothing agents • Oatmeal has soothing and anti-inflammatory effects • Antihistamines • Products containing diphenhydramine calm pain and itching due to allergic reactions and sensitive skin • Topical corticosteroids • Variety of products such as hydrocortisone, fluocinolone, triamcinolone, and betamethazone © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

6. Drugs Used inTreating Seborrhea • Seborrhea is characterized by abnormal flaking or scaling of the epidermis and may be accompanied by increased oil production (seborrhea oleasa) or not (seborrhea sicca) • Keratolytics are an important group of antiseborrheics • Keratolytics remove excess keratin and promote loosening of the outer layers of the epidermis • Keratolytics break down the protein structure of the keratin layer, permitting easier removal of this material © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

7. Drugs Used inTreating Seborrhea • Examples of topical antiseborrheics: • Sulfur: keratolytic, antipruritic, antibacterial, antifungal, and antiparasitic • Salicylic acid: keratolytic, antipruritic, and antibacterial • Coal tar: keratolytic and degreasing • Benzoyl peroxide: keratolytic, antipruritic, antibacterial, and degreasing • Selenium sulfide: keratolytic, degreasing, and antifungal © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.

8. Other Agents Used toTreat Skin Disorders • Astringents are agents that constrict tissues • Antiseptics are substances that kill or inhibit the growth of microbes on living tissue • Soaks and dressings are substances applied to areas to draw out fluid or relieve itching • Caustics are substances that destroy tissue • Counterirritants are substances that produce irritation and inflammation in areas of chronic inflammation • See Table 17-2 for examples of these agents © 2004 by Thomson Delmar Learning, a part of the Thomson Corporation.