Understanding Skin Diseases: Causes, Symptoms, and Treatments

1. Chapter 21 The Skin

2. Figure 21.1 Structure of the Skin.

3. The Skin • Epidermis—outermost layer of skin • Contains melanocytes, where pigment is stored • Thinnest skin layer

4. The Skin (cont.) • Dermis—middle layer of skin tissue • Contains fibroblasts responsible for secreting collagen and elastin • Contains immune cells, hair follicles, blood vessels, and sweat and oil glands • Location of the sensory receptors for touch, pain, heat, and cold • Helps maintain body temperature

5. The Skin (cont.) • Subcutaneous layer (hypodermis)—deepest layer of skin • Outermost part of the muscle is located here • Stores fat tissue • Contains connective tissue

6. Functions of the Skin • Acts as a mechanical barrier to infection • Provides for the sense of touch • Regulates body temperature • Excretes waste products and salt from the body • Synthesizes vitamin D (with sunlight) for the absorption of calcium

7. Diseases of the Skin—Rash • Area of red, inflamed skin, or a group of red spots • Caused by irritation, allergy, infection, or defects in the skin’s structure • Pharmaceutical treatment: antihistamines, topical corticosteroids

8. Diseases of the Skin—Eczema • Skin inflammation with red, pimple-like bumps • Characterized by itching, blistering, or oozing areas that progress to scaly, brownish, or thickened skin • Pharmaceutical treatment: topical immunomodulators

9. Diseases of the Skin—Psoriasis • Chronic immune disorder • Specific immune cells become overactive and release excessive amounts of proteins called cytokines • Causes inflammation and painful, often disfiguring plaques • Pharmaceutical treatment: topical steroids, oral antibiotics, immunosuppressants

10. Figure 21.2 Psoriasis of the abdomen.

11. Diseases of the Skin—Viral Infection • Occurs when a virus infects the inner layers of the skin • Examples: herpes simplex, warts, shingles • Pharmaceutical treatment: anti-inflammatory steroids or antihistamines

12. Diseases of the Skin—Bacterial Infection • Occurs when bacteria penetrate the skin and cause opportunistic infection • Most common bacterial infections: staphylococci, streptococci, and pseudomonas • If left untreated, may spread throughout the body, causing systemic infections • Examples: cellulitis, impetigo, folliculitis • Pharmaceutical treatment: oral antibiotics

13. Diseases of the Skin—Fungal Infection • Occurs when harmless fungi gain entry into the skin • Usually external, affecting the skin, hair, and nails • Examples: athlete’s foot, jock itch, ringworm • Pharmaceutical treatment: topical antifungals

14. Diseases of the Skin—Acne • Bacterial infection • Results in an overproduction of sebum, which clogs the hair follicles • Categorized as noninflammatory or inflammatory • Pharmaceutical treatment: topical antiseptics

15. Diseases of the Skin—Cellulitis • Acute, deep infection of the connective tissue • Accompanied by inflammation • Pharmaceutical treatment: oral or IV antibiotics

16. Diseases of the Skin—Parasitic Infestations • Caused by insects or worms that burrow into the skin to live and/or lay eggs • Examples: scabies, lice • Pharmaceutical treatment: antiparasitic topical agents

17. Figure 21.3 Parasitic infestation—head lice.

18. Diseases of the Skin—Tumors and Cancerous Growths • Occur when skin cells multiply or reproduce faster than normal • Cells without mutation are noncancerous or benign • Tumors or skin growths with mutation are cancerous or malignant • Pharmaceutical treatment: topical chemotherapeutic agents, immunomodulators, NSAIDs for precancerous actinic keratosis

19. Figure 21.4 Basal cell carcinoma.

20. Figure 21.5 Malignant melanoma.

21. Diseases of the Skin—Pigmentation Disorders • Skin color is determined by the amount of melanin produced by the body • Hypopigmentation—loss of skin pigmentation • Example: vitiligo • Hyperpigmentation—excess skin pigmentation • Examples: freckles, age or “liver” spots • Pharmaceutical treatment: none

22. Table 21.1 Drugs Used to Treat Various Skin Diseases

23. Table 21.1 (continued) Drugs Used to Treat Various Skin Diseases

24. Table 21.1 (continued) Drugs Used to Treat Various Skin Diseases

25. Table 21.1 (continued) Drugs Used to Treat Various Skin Diseases

26. Table 21.1 (continued) Drugs Used to Treat Various Skin Diseases

27. Table 21.1 (continued) Drugs Used to Treat Various Skin Diseases