skin & skin infections
Post on 08-May-2015
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- 1.STRUCTURE & FUNCTIONS OF SKIN
- The skin covers the whole of the external surface of the body.It forms the largest and heaviest organ in the body. The skin consists of three main layers.
- Epidermis (an upper protective layer)
- Dermis (a lower supporting layer)
- The epidermis is thick, hard and horny in regions, such as on the palms of the hand and soles of the feet.
- Primary barrier to microbial invasion
- Impermeability to water and chemicals
- High capacity of regeneration after damage
- The dermis is soft and elastic in all parts but may be very thick.
- The dermis gives strength to the skin
- Act as reservoir of elements capable of fighting infections and repairing deep wounds
- The skin is supported by a layer of fatty subcutaneous tissue sometimes known as the hypodermis.
6. FUNCTION OF SKIN
- The most obvious function of the skin is to provide the body with physical protection.
- It forms an outer covering, which defends the body against injury from mechanical, thermal, chemical sources and microorganisms
- The skin also acts as an organ of sensation to make the body aware of its environment.
7. FUNCTION OF SKIN (Contd)
- Another important function of the skin is regulation of body temperature (37-38C).
- It plays a minor role in excretion of the bodys waste products
8. Bacterial Structure
- CELL ENVELOPE:
- Protects cells internal structures from its external environment.
- It comprises cell wall, cell membrane
- Watery gelatinous substance
- Contains ribosomes, nucleoids & plasmids
- Keeps the cell alive
9. Bacterial Structure (Contd)
- Produces enzymes and proteins
- Helps the cell to live and grow
- Contains cells genetic material.
- Also called bacterial chromosome
- Single circular molecule of double stranded DNA
- DNA fragments carrying genetic information
- The study of fungi is called Mycology.
- There are several widespread human and animal diseases that are due to fungi.
- There are many beneficial fungi, some used to make antibiotics, bread and foods or used as insecticides.
11. CHARACTERISTICS OF FUNGI
- The fungi (sing., fungus) are a diverse group of eukaryotic microorganisms, with over 80,000 identifiable species.
- Fungi were classified as plants, but laboratory studies have revealed a set of four properties that distinguish fungi from plants.
12. Differentiation from Plants
- Fungi lack chlorophyll, while plants have this pigment.
- The cell walls of fungal cells contain a carbohydrate called chitin not found in plant cell walls.
- Fungi are not truly multi-cellular like plants.
- Fungi are heterotrophic eukaryotes, while plants are autotrophic eukaryotes.
13. GROWTH OF THE FUNGI
- Fungi are aerobic organism, with the notable exception of the yeasts that multiply in the presence or absence of oxygen.
- High concentration of sugar is favorable for thegrowth
- Most fungi grow best at approximately 25 C
- fungi grow under acidic conditions at a pH from 5 to 6
14. FUNGAL INFECTIONS OF THE SKIN
- Superficial Skin Infection
- Deep Fungal Infection
15. Superficial Skin Infection
- The superficial fungi live on the dead horny layer of the skin
- Secrete an enzyme that enables them to digest keratin causing the superficial skin to scale and disintegrate the nails, and the hairs to break off.
- Fungi are also capable of causing an allergic reaction.
16. CLINICAL CLASSIFICATIONS
- Tinea of the feet (tinea pedis) - T.mentagrophytes
- Tinea of the hands (tinea manus) -T. mentagrophytes
- Tinea of the nails (onychomycosis)T.rubrum, T. mentagrophytes
- Tinea of the groin (tinea cruris) - E.Floccosum
- Tinea of the smooth skin (tinea corporis) -T. mentagrophytes
- Tinea of the scalp (tinea capitis) -T.tonurans, T.verucosum
- Tinea of the beard (tinea barbae)
- Dermatophytid (Acute Eruption of Fungal Infection) Pityrosporum
- Tinea of Chest and Back (Tinea versicolor) Pityrosporum
17. DEEP FUNGAL INFECTION
- Fungi that invade the skin deeply and go into living tissue
- Also capable of involving other organs.
18. Types of Deep Fungal Infection
19. Deep Fungal Infection
- Candidiasis :
- Candidiasis is a fungal infection caused by Candida albicans that produces lesions in the mouth, the vagina, the nails, the lungs, or the gastrointestinal tract or occasionally a septicemia.
20. Deep Fungal Infection
- Sporotrichosis :
- Sporotrichosis is a fungal infection of the skin and the subcutaneous tissues that forms a chain of tumors that develop into ulcers
- Fungal infection of the skin ,especially of moist parts covered by clothing.
- Eczema is pruritic condition associated with erythema and edema in acute phase
- It is dominated by thickening and scaling when it becomes chronic
- The termeczemais broadly applied to a range of skin conditions.
- Eczema is defined as allergic, pruritic dermatitis
- Aprotective reaction of tissue to irritation, injury, or infection.
- Two types of Inflammation:
- Localized Inflammation
- Systemic Inflammation
- Symptoms includes pain, redness, swelling and heat.
24. Localized Inflammation
- Inflammation is a process in which the body's white blood cells and chemicals can protect us from infection and foreign substances (bacteria and viruses)
- Symptoms includes pain, redness, swelling and heat.
25. Systemic Inflammation
- Inflammation may also be associated with general "flu"-like symptoms including:
- Fatigue/loss of energy
- Muscle stiffness &myalgia
- A norexia(Loss of appetite)
26. ANTIFUNGAL AGENTS
- Clotrimazole is an imidazole antifungal agent.
- Clotrimazole is applied topically two or three times daily for 2 to 4 weeks as a 1% cream.
- Local reactions including irritation and burning may occur in patients treated topically; contact allergic dermatitis has been reported.
- Ketoconazole is an imidazole antifungal agent, which interferes with ergosterol synthesis and therefore alters the permeability of the cell membrane of sensitive fungi. It is reported to be fungistatic.
- After topical administration of Ketoconazole, irritation, dermatitis or a burning sensation has occurred
- Miconazole is an imidazole antifungal agent with similar antimicrobial activity to Ketoconazole.
- Local irritation and sensitivity reaction may occur with Miconazole nitrate
- Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex.
- Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation
30. Effects of Corticosteroids
- Corticosteroids exerts their effects by suppressing:
- The inflammatory response
- The immune response
31. Mechanism of Corticosteroids
- Corticosteroids suppress inflammation by a number of mechanisms:
- Inhibition of production of prostaglandins, leukotrienes and other inflammatory mediators
- Inhibition of migration of neutrophils to areas of inflammation
- Inhibition of accumulation of macrophages in areas of inflammation
- Hydrocortisoneis a corticosteroid hormone produced by the adrenal gland.
- It is usually referred to as the "stress hormone" as it is involved in response to stress.