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
◦ Cellulitis (erysipelas)
◦ Infection of the dermis and subcutaneous tissue
◦ Usually secondary to an injury
◦ May be iatrogenic
◦ Causative organism - Usually Staphylococcus aureus; Sometimes Streptococcus
◦ Frequently in lower trunks and legs
◦ Especially in individuals with restricted circulation in the extremities; also in immunocompromised individuals
◦ Area becomes red, swollen, and painful
◦ Red streaks may develop, running along lymph vessels proximal to infected area
Furuncles (boils) are usually caused by:
S. aureus
Carbuncles
◦ Collection of furuncles that coalesce to form a large infected mass
Impetigo
◦ Common infection in infants & children
◦ May also occur in adults
◦ S. aureus—highly contagious in neonates
◦ Lesions commonly on face
◦ Transmission may occur through close physical contact or through fomites
◦ Pruritus common - Leads to scratching and further spread of infection
Impetigo treatment
◦ Topical antibiotics in early stages
◦ Systemic administration if lesions are extensive
-Antibiotic-resistant strains of S. aureus are increasing in numbers.
-Local outbreaks of infection may result.
Acute Necrotizing Fasciitis
Cause/Sx
◦ Mixture of aerobic & anaerobic bacteria usually at site of infection
◦ Severe inflammation and tissue necrosis
◦ Usually caused by virulent strain of gram-positive, group A betahemolytic Streptococcus
-Bacteria secrete toxins that break down fascia and connective tissue, causing massive tissue destruction.
◦ Delay in treatment—greater tissue loss, potential amputation, chance of mortality
◦ Systemic toxicity develops with fever, tachycardia, hypotension, mental confusion, disorientation, possible organ failure
Acute Necrotizing Fasciitis
treatment:
◦ Aggressive antimicrobial therapy, fluid replacement
◦ Excision of all infected tissue; amputation
Leprosy (Hansen’s Disease) is caused by:
affects:
treatment:
Mycobacterium leprae
◦ Generally affects skin, mucous membranes, and peripheral nerves
◦ Damage can lead to loss of limbs.
◦ Treatment primarily with antibiotics
Herpes Simplex
◦ Herpes simplex type 1 (HSV-1) - cause of ________________________
◦ Herpes simplex type 2 (HSV-2)—____________
◦ Both types of HSV cause similar ___________
◦ Primary infection may be asymptomatic
◦ Virus remains latent in sensory nerve ganglia.
◦ Recurrence may be triggered by: ______________________________________________
◦ Spread by direct contact with fluid from lesion
◦ Spread of infection to others possible prior to appearance of lesions
-Complications:
◦ Spread of virus to eye, Keratitis, Herpetic whitlow, Painful infection of the fingers
◦ Herpes simplex type 1 (HSV-1) - cause of cold sores/fever blisters
◦ Herpes simplex type 2 (HSV-2)—genital herpes
◦ Both types of HSV cause similar effects.
◦ Primary infection may be asymptomatic
◦ Virus remains latent in sensory nerve ganglia.
◦ Recurrence may be triggered by: common cold, sun exposure, stress
◦ Spread by direct contact with fluid from lesion
◦ Spread of infection to others possible prior to appearance of lesions
-Complications:
◦ Spread of virus to eye, Keratitis, Herpetic whitlow, Painful infection of the fingers
Verrucae (Warts)
◦ Human papillomavirus (HPV) types 1 - 4
◦ Frequently develop in children and young adults
◦ Plantar warts are common.
◦ Spreads by viral shedding of the skin surface
◦ May resolve spontaneously with time
◦ Genital warts (HPV types 6 & 11)
◦ Candida infection is associated with:
diabetes.
Most fungal infections are:
superficial
Tinea capitis
◦ Infection of the scalp
◦ Common in school-age children
◦ Erythema may be apparent.
◦ Oral antifungal medication
Tinea corporis
◦ Infection of the body, particularly of nonhairy parts
◦ Round lesion with clear center (ringworm)
◦ Pruritus may be present.
◦ Topical antifungal medication
Tinea pedis
◦ Athlete’s foot—involves feet, particularly toes
◦ Associated with swimming pools & gyms
◦ May be part of normal flora that becomes opportunistic
◦ Secondary bacterial infection may occur
◦ Topical antifungal medication
Tinea unguium
◦ Infection of the nails, particularly toenails
◦ Nails turn white, then brown.
◦ Nail thickens and cracks.
◦ Infection tends to spread to other nails.
Scabies
◦ Invasion by mite Sarcoptes scabiei
-Female burrows into epidermis; lays eggs over several weeks
-Male dies after fertilizing; Female dies after laying the eggs.
◦ Larvae migrate to skin surface > Burrow into skin in search of nutrients
- Intensively pruritic!
◦ Larvae mature and cycle is repeated
◦ Burrows appear on skin as tiny, light brown lines.
Pediculosis (lice)
◦ Pediculus humanus corporis—body louse
◦ Pediculus humanus capitis—head louse
◦ Pediculus humanus pubis—pubic louse
◦ Female lice lay eggs on hair shafts.
◦ After hatching, louse bites human host, sucking blood for production of ova
◦ Excoriations result from scratching
Keratoses
◦ Benign lesions usually associated with aging or skin damage.
◦ Seborrheic keratoses- Proliferation of basal cells; Lead to oval elevation; May be smooth or rough
◦ Actinic keratoses- On skin exposed to ultraviolet radiation; Commonly in fair-skinned persons; Lesion appears as pigmented, scaly patch
Guidelines to Reduce Risk
of Skin Cancers
◦ Reducing sun exposure
◦ Covering up with clothing
◦ Remaining in shade
◦ Wearing brimmed hats to protect face & neck
◦ Applying sunscreen/sunblock
Squamous Cell Carcinoma
◦ Painless, malignant tumor of the epidermis
◦ Lesions most commonly found on exposed areas of the skin but also in oral cavity- Face, neck, Base of tongue
◦ Excellent prognosis when lesion is removed within reasonable time
◦ Invasive type arises from premalignant condition.
Malignant Melanoma
◦ Highly metastatic form of skin cancer
◦ Develops in melanocytes from a nevus (mole)
◦ Often appear as multicolored lesion with irregular border
-Grow quickly, Change in shape, color, size, texture; May bleed
◦ Treatment: surgical removal and radiation plus chemotherapy
The ABCD of Melanoma
◦ Melanoma is suspected in any nevus that shows:
◦ Change in appearance
◦ Change in border
◦ Change in color
◦ Increase in diameter
Kaposi’s Sarcoma
◦ Occurs in those with AIDS and other immunodeficiencies
◦ May affect viscera & skin
◦ Malignant cells arise from endothelium in small blood vessels
-Purplish macules; Nonpruritic, nonpainful
◦ In immunocompromised, lesions develop rapidly over upper body.
Treatment: Combo of radiation, chemotherapy, surgery, biological therapy
Plantar warts are caused by:
human papillomavirus.
Which of the following statements regarding acute necrotizing fasciitis is TRUE?
It is usually caused by S. aureus.
Infection is localized in a small area of the epidermis.
Spontaneous recovery usually occurs in 48 hours.
Infection rapidly causes extensive tissue necrosis and toxic shock.
Infection rapidly causes extensive tissue necrosis and toxic shock.
Which type of microbe causes Tinea infections?
Fungus
What causes the pruritus associated with scabies?
Mites burrowing into the epidermis and reaction to their feces
How can pediculosis be diagnosed?
The presence of nits at the base of hair shafts
[lice]
What is the major predisposing factor to squamous cell carcinoma?
Exposure to ultraviolet light
All of the following statements apply to malignant melanoma EXCEPT:
The malignant cell is a melanocyte.
The neoplasm grows rapidly and metastasizes early.
The lesion is usually dark or multicolored with an irregular border.
They present as non-pruritic purplish macules.
They present as non-pruritic purplish macules.
What factor has contributed to the increased incidence of Kaposi’s sarcoma?
immunosuppressed individuals
The cause of contact dermatitis can often be identified by:
noting the location and size of the lesion.
Scabies—usually on the:
fingers, wrists, waist
Leprosy (Hansen’s disease) is caused by:
a bacterium.
Impetigo is highly:
contagious
