Therapeutic Agents for the Dermatological System

Transcription

1 Therapeutic Agents for the Dermatological System Chapter 25 1 Anatomy of the Skin Skin is made of various layers that contain nerves, glands, hair, and blood vessels Function is to protect the body against heat, cold, light, dehydration, and infection Nerves allow the skin to detect pain, heat, and cold Three main layers: Epidermis Dermis Subcutaneous layer The skin has a covering of hair as added protection. The skin is the largest organ of the body. It is made of various layers that contain nerves, glands, hair, and blood vessels. The functions of the skin include protecting the body against heat, cold, light, dehydration, and infection. Nerve endings within the skin allow for the perception of pain, heat, and cold. 2 Hair and Nails Made of proteins called keratin Melanocytes determine color of hair Lunula: The small white portion located at the base of the nail Two glands within the layers of the skin: Sebaceous: Secrete sebum to provide moisture Sweat: Perspiration to provide cooling Keratin is a hard substance. Alopecia is the loss of hair or the partial or complete absence of hair from areas of the body where it normally grows (baldness). It can be caused by a variety of medical conditions and medications. Sebaceous glands in the skin are responsible for the secretion of oil called sebum. 3

2 Acne Vulgaris Cause is inflammation of sebaceous glands Rise in sebum production due to hormones Symptoms: Greasy residue on the surface of the skin; lesions on the face, back of the neck, chest, shoulders, back, and upper arms The old belief that eating too much candy or greasy food (such as fries) causes acne is incorrect. Mild acne is often treated with topical agents such as benzoyl peroxide, which helps dry the skin, and salicylic acid, which increases skin turnover. The auxiliary labels needed on a prescription for tetracycline include: Do not take with dairy products. Separate from antacids or iron supplements by 4 hours. Take on an empty stomach. Take with a full glass of water. Avoid exposure to sunlight or tanning beds. 4 Acne Vulgaris (Cont.) Most non-drug treatment involves keeping the skin clean. Many over-thecounter products are available. Five categories of lesions: Whiteheads Blackheads Papules Pustules Scars Cleansing agents to decrease sebum production 5 Drug Treatment for Acne Vulgaris Topical agents for mild acne: Benzoyl peroxide, salicylic acid Severe acne: Topical or systemic antibiotics or topical retinoids in addition to keratolytics Oral retinoid therapies (such as isotretinoin) require that the prescriber, pharmacy, and patient be enrolled in a special program called ipledge. Sotret is oral isotretinoin, whereas Retin-A and Renova are topical tretinoin creams. Topical retinoid agents such as tretinoin (Retin-A Micro) increase the growth of skin around the acne areas, which causes exfoliation of the skin and removes dead skin cells, decreasing the formation of comedones. OTC keratolytic agents such as Compound W, which contain salicylic acid, can be used for the treatment of common warts and plantar warts. A keratolytic drug causes shedding of the outer layer of the skin. An emollient softens the skin, and a xerotic drug dries the skin. An antiseptic stops the growth of microorganisms. 6

3 Also known as hives Urticaria Caused by hypersensitivity to food, environment, and drugs Treatment: Apply cold compress Drug treatment: Antihistamines Topical agents can be used for hives and other noninfectious inflammatory skin rashes. If an antihistamine is needed, an oral one (such as oral diphenhydramine) can dramatically reduce the appearance of hives and itching; however, drowsiness is a common side effect of diphenhydramine, so patients should be cautious when using such products. Pruritis means itching. 7 Eczema Also known as atopic dermatitis Inflammatory skin condition Treat immune system Affects 5% to 20% of children worldwide Antihistamines, antiinfectives, and corticosteroids for inflammation Maintaining hydration is a major factor in treatment. There is no cure for eczema, and constant treatment is required. Topical calcineurin inhibitors (e.g., tacrolimus, pimecrolimus) can be used for eczema. Tacrolimus is also available orally for organ transplant rejection prophylaxis under the trade names Prograf and Hecoria. Treatment of eczema may include topical corticosteroids, oral and topical calcineurin inhibitors, and immunosuppressants. 8 Psoriasis Psoriasis is an inflammatory skin disorder Most affected areas are around the joints, limbs, neck, and scalp Often appears as plaques of silvery scales, which vary in size Need high-quality moisturizer to keep the skin moist and to help control flare-ups Ultraviolet light exposure causes sunburn and peeling Emollients that trap moisture work best. However, it may take time to determine which products are most effective. No cure is currently available for psoriasis. Three types of agents are used to treat psoriasis: topical agents, phototherapy, and systemic agents. Application of topical agents over the affected area(s) is usually the first line of treatment. Adalimumab (Humira), golimumab (Simponi), and ustekinumab (Stelara) are all subcutaneously administered to treat psoriasis. 9

4 Refer to Table 25-3 (p. 639). Drug Treatment for Psoriasis Topical agents: Colloidal oatmeal and tarbased shampoos Phototherapy: Ultraviolet B light and sunlight Systemic agents 10 Chickenpox and Shingles Non-serious symptoms of chickenpox: Skin blisters, fever, and itchy rash Can require hospitalization in pregnant women Shingles: Can appear in a child who had chickenpox Symptom: Painful lesions along nerves Treatment: Medications valacyclovir (Valtrex) and acyclovir (Zovirax) Some people can experience more severe effects, such as brain damage, pneumonia, infection, or (rarely) even death. After lying dormant for several years, the virus may become activated and cause acute inflammation of the dorsal root ganglia. The vaccine prevented shingles in about half the subjects tested and can reduce the pain associated with this condition. Shingles is a disorder caused by the same virus that causes chickenpox (herpes zoster), which may appear in adulthood in a person who had childhood chickenpox. After lying dormant for several years, the virus may become activated and cause acute inflammation of the dorsal root ganglia. Symptoms include painful lesions along the nerves. Treatment for shingles includes medications such as valacyclovir (Valtrex), which can be given orally or intravenously. Acyclovir (Zovirax) may also be taken over a 7-day period to reduce pain and to promote healing. In 2006, a single-dose vaccine was introduced for adults older than age 60 years of age. 11 Burns Burns range in severity from first to fourth degree Burn hospitals require specialized solutions and medications Patients with severe burns over a large surface area can be at high risk for infection, sepsis, and death For substantial burns, surgery may be needed Treatment depends on severity and type of burn Topical medications: Silver cream (sulfadiazine [Silvadene]) and bacitracin ointment Refer to Box 25-1 (p. 641) to learn more about the different degrees of burns. Fourth-degree burns may require treatment with skin grafting. Topical burn medications include silver sulfadiazine (Silvadene) cream and bacitracin ointment. Neosporin is a triple antibiotic cream or ointment containing bacitracin, neomycin, and polymyxin B sulfate. 12

5 Human papillomavirus is HPV. Warts Caused by a virus that causes growths on the skin Verruca plana commonly seen in children Plantar warts found on bottom of feet Genital warts are a different strain of HPV 13 Common warts normally disappear over time without treatment. Drug Treatment for Warts Common warts: OTC agents that contain salicylic acid or those that freeze the wart Plantar warts: Topical fluorouracil (Carac, Efudex, Fluoroplex) Genital warts: Imiquimod topical (Aldara) or podofilox (topical gel or solution) 14 Athlete's Foot Antifungal drugs are used to kill fungi and treat athlete s foot, with OTC products usually available in powder, cream, or spray formulations. Clotrimazole, an azole antifungal medication, is available OTC under the brand name of Lotrimin AF. Ketoconazole is an antifungal treatment. Tinea pedis is a fungus that causes scaling and blisters between the toes Severe infections may cause inflammation along with severe itching and pain It is spread by contact from shower floor surfaces, clothing, and sharing socks Topical antifungals Powder or spray Oral antifungals for infection Systemic therapy if infection affects nails 15

6 Impetigo Caused by streptococcal organisms or Staphylococcus aureus Areas affected: Face, limbs, and abdomen Symptoms: Thick yellow crust that is itchy, oozing, and blistering Topical antibiotics: Mupirocin 2% ointment (Bactroban, Centany) or retapamulin 1% ointment (Altabax) Antibiotics: Penicillins (dicloxacillin or Augmentin) or cephalosporins (Keflex or Ceftin) Impetigo reaches the body through broken skin. Sores heal slowly, and children may have reoccurrences. Impetigo is a highly contagious condition caused by streptococcal organisms or S. aureus. Children may have recurrences of the condition. Treatment includes topical or oral antibiotics. Treatment for impetigo includes topical antibiotics such as mupirocin 2% ointment (Bactroban, Centany) or retapamulin 1% ointment (Altabax); these antibiotics are effective for limited areas and have the advantage of no systemic side effects. Bactroban is a topical prescription antibiotic with the generic name of mupirocin. 16 Skin Cancer Melanomas: Cancerous skin growths from moles or sunburned skin Three types: Melanoma, squamous cell, and basal cell Characteristics of melanoma: Irregular shape, elevated off skin, and discoloration Treatment depends on severity of cancer Prognosis depends on several factors Protect self from harmful sun rays Treatment: Radiation, photodynamic therapy, and chemotherapy Any abnormal growth of new skin tissue that results in a malignancy is known as skin cancer. Melanomas start in the lower part of the epidermis, in the melanocytes (cells that color the skin). The top portion of the skin-the epidermis-can be further divided into three primary layers: the horny outer layer, a layer of squamous cells, and the basal layer. The epidermis is the outermost layer and serves to protect the layers below it. It contains melanocytes, which produce the skin pigment melanin. The epidermis does not have a blood supply of its own; rather, it receives nutrition from the tissues surrounding it. The subcutaneous layer or hypodermis is the deepest layer and contains fat cells that help insulate the body. Individuals with light-colored or freckled skin, red- and blond-haired people, and Caucasians age 20 or older are at higher risk. 5-FU topical for basal cell carcinoma should be applied using gloves or a nonmetal applicator. Hands should be thoroughly washed after applying since it is an antimetabolite that inhibits cancer cells from synthesizing deoxyribonucleic acid (DNA). 5-FU can cause the skin to be very sensitive to sunlight. 17 Head Lice Head lice are caused by the parasite Pediculus humanus capitis Another type of lice affects the pubic area; spread through sexual contact Physical removal of all nits is essential to adequately treat lice of any type If treated correctly, lice can be eliminated. OTC agents are available to treat head lice, such as permethrin (Nix) topical cream rinse, Medi-Lice, Pronto, and pyrethrins and piperonyl butoxide pesticides (Tegrin LF) as shampoos. Prescription treatments include malathion (Ovide) topical and lindane (Kwell) shampoos and lotions, which are reserved for resistant cases. 18

7 Drug Treatment for Lice All brushes, combs, and hats must be cleaned in hot, soapy water or alcohol and should not be shared. OTC agents Permethrin (Nix) topical cream rinse Medi-Lice, Pronto, and pyrethrins and piperonyl butoxide (Tegrin LF) as shampoos Prescription Malathion (Ovide) topical Lindane (Kwell) shampoos and lotions 19 Onychomycosis Onychomycosis is caused by a fungus and is the most common disease of the nails. Antifungal drugs are the treatment. Lamisil is the most common drug used in treatment. Onychomycosis: Infection of the nails Infection normally starts at the tip of one or more toenails; produces thickening of, discoloration, and crumbling of the nail Topical antifungals: Ciclopirox olamine 8% lacquer solution Oral antifungals: Terbinafine (Lamisil) 20