Week 2: Ch. 8- Skin Disorders Flashcards
Keratin - ______________ of the skin
Waterproofing
Describe melanin
Skin pigment—determines skin color
◦ Production depends on multiple genes and environment
Albinism: Lack of
melanin production
Vitiligo- Small areas of :
hypopigmentation
Melasma- patches of :
darker skin
Describe the dermis
◦ Connective tissue
◦ Contains elastic & collagen fibers
◦ Flexibility and strength of the skin
◦ Contains nerves and blood vessels
Includes sensory receptors for:
◦ Pressure
◦ Touch
◦ Pain
◦ Heat
◦ Cold
Arrector pili muscle associated with :
hair follicle
Sebaceous glands
◦ Produce sebum
◦ Secretion increases at puberty—influence of sex hormones
Sweat glands
◦ Eccrine—all over body
◦ Apocrine -Axillae, scalp, face, external genitalia
Describe the hypodermis
Beneath dermis
◦ Connective tissue
◦ Fat cells
◦ Macrophages
◦ Fibroblasts
◦ Larger blood vessels
◦ Nerves
5 Functions of the Skin
◦ Acts as first line of defense
◦ Prevents excessive fluid loss
◦ Controls body temperature
◦ Active in sensory perception
◦ Synthesizes vitamin D
Skin lesions may be caused by:
◦ Systemic disorders - Liver disease
◦ Systemic infections - Chickenpox
◦ Allergies to ingested food or drugs
◦ Localized factors - Include exposure to toxins
Pruritus (itching) is associated with:
◦ _________ responses
◦ Chemical irritation caused by _________________
◦ Infestations by ___________________
◦ Allergic responses
◦ Chemical irritation caused by insect bites
◦ Infestations by parasites (e.g., scabies)
Diagnostic Tests for Skin Lesions
◦Culture and staining of specimens
-Bacterial infections: microscopic/ direct observations
-Specific procedures for fungal or parasitic infections
◦ Biopsy
-Detection of malignant changes
-Safeguard prior to or following removal of skin lesions
◦ Blood tests - Helpful in diagnosis of conditions caused by allergy or abnormal immune reaction
◦ Skin testing using patch or scratch method
General treatment for pruritus
◦ Topical agents to reduce sensation
◦ May be treated by antihistamines or glucocorticoids
General treatment for precancerous lesions
◦ Surgery, laser therapy, electrodessication, cryosurgery
Urticaria (Hives)
◦ Result of type I hypersensitivity
◦ Ingestion of substances- examples: shellfish, drugs, certain fruits
◦ Lesions are highly pruritic.
◦ Hives are often part of anaphylaxis!
◦ Check for swelling around mouth & check airway.
◦ Administer EpiPen or other first aid as required.
Describe Contact Dermatitis
◦ Exposure to_____________________________________________________
◦ Pruritic rash develops at site a few ________ after exposure.
◦ Direct _________________________________________________ irritation
◦ Does not involve ________________ response
◦ Is inflammatory because of direct exposure
—Removal of irritant; Reduction of inflammation with topical glucocorticoids
◦ Exposure to an allergen
[Metals, cosmetics, soaps, chemicals, plants]
◦ Pruritic rash develops at site a few hours after exposure.
◦ Direct chemical or mechanical irritation
◦ Does not involve immune response
◦ Is inflammatory because of direct exposure
—Removal of irritant; Reduction of inflammation with topical glucocorticoids
Atopic Dermatitis (Eczema)
◦ Atopic—inherited tendency
◦ Common problem in infancy
◦ Rash is erythematous, with serous exudate.
◦ Commonly occurs on face, chest, and shoulders; rash is dry, scaly, and pruritic, often on flexor surfaces.
◦ Chronic inflammation results from response to allergens.
◦ Eosinophilia and increased serum IgE levels
◦ Potential complication—secondary infections
◦ Treatment: Topical glucocorticoids, antihistamines
Psoriasis
◦ Chronic inflammatory skin disorder
◦ Onset usually in the teenage years
◦ Psoriasis results from abnormal T cell activation.
-Excessive proliferation of keratinocytes
-Cellular proliferation is greatly increased.
◦ Lesions found on face, scalp, elbows, knees
◦ Itching or burning sensations
◦ Treatment: Glucocorticoids, tar preparations, antimetabolites
Pemphigus
◦ Autoimmune disorder
◦ Autoantibodies disrupt cohesion between _______________________
-Causes ___________________________ to form
-Skin sheds, leaving area painful and open to secondary infection.
◦ May be life-threatening if extensive (e.g., Stevens-Johnson syndrome)
Treatment: Systemic glucocorticoids and immunosuppressants
◦ Autoimmune disorder
◦ Autoantibodies disrupt cohesion between epidermal cells.
-Causes blisters (bullae) to form
-Skin sheds, leaving area painful and open to secondary infection.
◦ May be life-threatening if extensive (e.g., Stevens-Johnson syndrome)
Treatment: Systemic glucocorticoids and immunosuppressants
Scleroderma
◦ May be systemic and affect viscera
◦ Primary cause:______________
-Increased _____________ deposition in all cases
-Inflammation & fibrosis w/ decreased capillary networks
◦ Hard, shiny, tight, ____________________ areas of skin
◦ Impaired movement of mouth and eyes
◦ May cause _________ failure, intestinal obstruction, ____________ failure caused by distortion of tissues
◦ May be systemic and affect viscera
◦ Primary cause unknown
-Increased collagen deposition in all cases
-Inflammation & fibrosis w/ decreased capillary networks
◦ Hard, shiny, tight, immovable areas of skin
◦ Impaired movement of mouth and eyes
◦ May cause renal failure, intestinal obstruction, respiratory failure caused by distortion of tissues
Skin Infections may be caused by:
bacteria, viruses, fungi, other types of
microbes, parasites
◦ Caused by opportunistic microbes
◦ Minor abrasions or cuts
Cellulitis (erysipelas) is a
Bacterial Infection
