Dermatology Flashcards
Primary functions of the skin
protect body from microorganisms, control body heat, eliminate waste through perspiration, prevent injury to the core. Peripheral receptors alert the body to pain, temperature changes and touch
Three layers of the skin
Epidermis, Dermis, and Hypodermis
Macule
Skin color change without elevation. Ex - freckle, petechia Patch if greater than 1cm.
Papule
Elevated solid lesion less than 1cm, varying in color. Ex - warts
Plaque
Raised, flat lesion formed from merging papules or nodules
Nodule
Larger than a papule, extends into the dermis deeper. Raised and solid. Large nodule is a tumor
Wheal
fleeting skin elevation, irregular shape d/t edema ex - mosquito bite
Vesicle
Elevated, sharply defined margins,
Bulla
Larger than 1cm fluid filled elevated. Ex - partial thickness burn
Cyst
Elevated thick walled lesion containing fluid or a semi solid matter
Pustule
Elevated lesion less than 1cm with purulent material. Larger than 1cm is a boil, abscess or furuncles
Scale
Dried fragment of sloughed epidermal cells, irregular in shape and size. White, yellow or silver. ex - dandruff, dry skin, psoriasis
Erosion
Moist, demarcated, depressed area with partial or full thickness loss of epidermis. Dermis intact. Ex - ruptured chicken pox
Deep Ulcer
All of epidermis and all or part of the dermis is lost. Irregular, exudative, depressed. From trauma like pressure ulcer
Lichenification
Epidermal thickening causing elevated plaque with accentuated skin markings from repeated scratching or injury like in chronic atopic dermatitis
Excoriation
superficial linear abrasion of epidermis, visible sign of itching
Fissure
deep split from epidermis to dermis ex - tinea pedis
Keloid
irregularly shaped elevated progressively enlarged scar, extending beyond boundaries of the wound, caused by excessive collagen formation
Derm evaluation
by morphology, region or diff dx
most frequent cause of malpractice in derm
failure to dx
inspection of the skin
note color, moisture, temp, texture, mobility, turgor, lesions
color changes in skin
increase pigmentation, decreased pigmentation, redness, pallor, cyanosis, yellow
red color of oxyhemoglobin best assessed
fingertips, lips, mucus membranes. dark skinned: palms and soles
central cyanosis
lips, oral mucosa and tongue
jaundice
sclera
ease in which skin moves up/skin returns to normal
mobility/turgor
technique of exam for lesions
characteristics of anatomic location, patterns and shapes, type of lesion, color. To have a dx: Determine the type of lesion, location and distribution along with the patient’s h&p.
inspect hair
inspect and palpate, note quality and distribution, texture, any infestations
inspect nails
color and shape, lesions, longitudinal bands of pigment may be common in people with darker skin
three layers of skin starting from the inside going out
subcutaneous tissue, dermis and epidermis
epidermal appendages
hair, sebaceous glands, sweat glands (eccine and apocrine), nails
epidermis
thin but tough - DEVOID of blood vessels. tightly bound cells that are replaced every 4 weeks. STRATIFIED zones starting wit hthe stratum germinativum “basal cells”, blend of keratin and melanin
dermis
inner supportive layer, connective tissue collagen, tough - helps to resist tearing, elastic with resilient capacity, placement of the nerves, sensory receptors, BLOOD VESSELS and lymphatics
subcutaneous layer
adipose tissue - fat, stores the fat for energy, provides insulation, soft cushioning effect
four appendages: 1) hair
VESTIGIAL: no longer needed for protection from cold or trauma, threads of keratin, held in place from arrector pili which contract and elevate the hair - goosebumps, two types: fine/faint = vellus, course/thick = terminal
2) sebaceous glands
produces a protective lipid substance which is secreted through hair follicles, lubricates the skin and hair, abundant in the scalp, face, forehead and chin
3) sweat glands - two types
eccrine and apocrine
eccrine glands
coiled and open directly onto the skins surface. produces diluate saline sweat. as sweat evaporates, body temperature is controlled. floods the skin with sweat for cooling. abundant on the body and mature by 2months. greatest number on the palms, soles and forehead. controlled by the hypothalamic thermostat
apocrine glands
thick milky secretion that opens into the hair follicle, mainly in the axillae, anogenital nipple and navel area. VESTIGIAL in humans. becomes active during puberty increased by emotional stress and sexual stimulation. normal flora reacte with apocrine sweat to create body odor. represents scent glands. does not develop until puberty. little purpose except production of odor. adrenergic sympathetic discharge from the apocrine glands. function decreases with the aging adult.
4) nails
hard palate of keratin, longitudinal ridges become prominent in aging, appears pink from the underlying vascular epithelial cells, new keratinized cells start in the lunula
subcutaneous tissue
serves as a receptor for the formation and storage of fat, dynamic lipid metabolism, insulates the body from extremes in temperature, supports blood vessels and nerves, site of origin for sweat glands and follicles, cushions the body, sythesizes vitamin D, heaviest single organ in the body 16 percent of body weight
the dermis
the mechanical properties of the skin depend mainly on the dermis, achieved by collagen and elastic fibers, contains blood, lymph and peripheral nerves
stratum corneum
outer horny layer of the dermis, effective barrier against water and electrolyte loss, effective barrier against penetration of toxic agents and UV radiation, intact it will prevent the invasion of normal bacteria into the blood stream, low water content with a high electrical resistance protects against low voltage electric current
stratum mucosum
contains langerhan cells, functions as antigen-presenting cells that migrate to the lymph, play an important role in allergic response.
five layers to the epidermis
basal, prickle, granular, living epidermis. lucid, horny - the dea end product
hair
grows at different rates at different regions, in women, scalp and body hair grows faster than in men.
anagen
active period, may last for 3 or more years
telogen
resting phase, usually lasting 3 months
catagen
transition phase or regression phase, usually 3 weeks
wound repair occurs in three stages
inflammation, proliferation and tissue formation, and tissue remodeling. wound healing begins immediately. platelets dominate the early stages of wound healing – activate coagulation cascade, chemotaxis of other inflammatory cells, and clot formation
differentiate between primary and secondary lesions
commonly, primary lesions have been obliterated by secondary via scratching, infection or over treatment. can find primary at the edge of an eruption or on less irrated parts of the body. look for the morphologic appearance of the lesions and distribution, arrangement and the number of lesions present
What is this?
A circumscribed, flat lesion with color change, up to 1 cm in size, although the term is often used for lesions >1 cm. By definition, they are not palpable. picture: cafe-au-lait macule.
What is this?
A circumscribed, flat lesion with color change, >1 cm in size. hemangioma precursor.
What is this?
A circumscribed, elevated, solid lesion, up to 1 cm in size. Elevation may be accentuated with oblique lighting. Umbilical granuloma. Papule.
What is this?
A circumscribed, elevated, plateau-like, solid lesion, >1 cm in size. Plaque. Nevus sebaceus.
What is this?
A circumscribed, elevated, solid lesion with depth, up to 2 cm in size. Nodule. Juvenile xanthogranuloma
What is this?
A circumscribed, elevated, fluid-filled lesion >1 cm in size, bulla. Insect bite reaction.
What is this?
A circumscribed, elevated lesion filled with purulent fluid, <1 cm in size. Pustules can be primary skin lesions or can initially be a vesicle that then becomes filled with cells or debris. Pustule, common acne.
What is this?
A circumscribed, elevated, edematous, often evanescent lesion, caused by accumulation of fluid within the dermis. Wheel. Urticaria, bite reactions, drug eruptions.
What is this?
A circumscribed, elevated lesion filled with purulent fluid, >1 cm in size. Common adult abscess.
What is this?
Results from dried exudate overlying an impaired epidermis. Can be composed of serum, blood, or pus - Crust.
What is this?
Results from increased shedding or accumulation of stratum corneum as a result of abnormal keratinization and exfoliation. Can be subdivided further into pityriasiform (branny, delicate), psoriasiform (thick, white, and adherent), and ichthyosiform (fish scale-like)
What is this?
Intraepithelial loss of epidermis. Heals without scarring. Herpes simplex, certain types of epidermolysis bullosa — erosion.
What is this?
Full-thickness loss of the epidermis, with damage into the dermis. Will heal with scarring. Ulcerated hemangiomas, aplasia cutis congenita — ulcer
What is this?
Linear, often painful break within the skin surface, as a result of excessive xerosis – fissure
What is this?
Thickening of the epidermis with exaggeration of normal skin markings caused by chronic scratching or rubbing – atopic dermatitis – lichenification
What is this?
Localized diminution of skin. Epidermal atrophy results in a translucent epidermis with increased wrinkling, whereas dermal atrophy results in depression of the skin with retained skin markings.
Use of topical steroids can result in epidermal atrophy, whereas intralesional steroids may result in dermal atrophy
What is this?
- Description: Multiple, large, well-demarcated, hypopigmented patches
- Vitiligo results from progressive destruction of melanocytes
- Associated with autoimmune diseases such as Hashimoto’s Thyroiditis, Addison’s Disease, and Pernicious Anemia.
•SO…this means what????
What is this?
Urticarial wheals with white-to-pink centers appearing on the trunk of an individual several hours after?
What is this?
•Seborrheic Dermatitis with Neonatal Acne •a common greasy yellow-red scaling rash that occurs on the scalp and forehead of infants.
What is this?
pseudofolliculitis barbae.
- Papular pustular eruption occuring on the nape of the neck of this patient.
- Pseudofolliculitis barbae can be caused by hair growing back into the skin and triggering an inflammatory reaction.
What is this?
Autosomal dominant disease characterized by changes in the skin, nervous system, endocrine glands, and bones •Multiple skin-colored, soft papules and pedunculated nodules on her abdomen – neurofibroma
What is this?
Autosomal dominant disorder and may develop into malignant melanoma many years later in life
•Dysplastic nevi exhibit some or all of the following features:
- 1) > 5 mm diameter,
- 2) irregular, indistinct borders,
- 3) macular with or without raised areas,
- 4) mottled colors including tan, brown, black, pink, or red.
What is this?
•The papular urticarial lesions often result in post inflammatory pigmentation, leaving dark spots. Flea bites
What is this?
Dermographism•A sharply demarcated pruritic erythematous urticaria in the shape of the word “HI”
What is this?
Paronychia of Great Toe
•Paronychia is a bacterial infection of the nail fold. Chronic paronychia is usually due to chronic irritant exposure, and may be confused with the nail changes of psoriasis. can also occur secondary to allergic contact dermatitis, indinavir, lichen planus, candida, or a foreign body (i.e. a splinter). Chronic paronychia causes the cuticle to disappear, leaving the nail fold even more open to further infection. Many or all fingers are involved in chronic paronychia. Acute paronychia is normally caused by trauma or manipulation, although it can occur idiopathically. Both acute and chronic paronychia are painful and cause pus to build up underneath the cuticle.
dx/tx paronychia of the great toe
•Insertion of an instrument between the nail and the nail fold will cause the pus to drain, dramatically and immediately relieving the pain. Based on clinical findings. TREATMENT: topical steroids, avoidance of irritants, and antistaphylococcal antibiotics for secondary infection. Treat acute paronychia with surgical drainage. Treat large erythematous abscesses with antistaphylococcal antibiotics.
What is this?
Onychomycosis
•White, yellow, or brown discoloration and subsequent breakdown of the distal toenail down to the nailbed characterizes distal subungual onychomycosis, most common form of fungal nail infection. Beginning distally with proximal progression towards the cuticle, the nail may become irregular, thickened, or eroded. great toe is usually the first affected, although several (but rarely all) nails on the foot may eventually be involved. Tinea pedis may coexist or precede nail involvement.
dx Onychomycosis
- In order to rule out nail dystrophies that can mimic onchomycosis, confirmation of the presence of fungus should be performed prior to antifungal treatment.
- For distal subungual onychomycosis, KOH examination of nail scrapings is the first step.
- Visualization of dermatophytic hyphae and arthrospores confirms the diagnosis.
- Scrapings should be taken from the most proximal affected area.
- If negative, nail culture can be performed and may need to be repeated due to a high probability of false negatives.
tx Onychomycosis
•Topical treatment is ineffective. Oral antifungal therapy (terbinafine) is preferred although high failure and recurrence rates still exist such that treatment is usually reserved for patients complaining of nail pain, patients desiring treatment for cosmetic reasons, and diabetics or others at high risk for cellulitis.
What is this?
diabetic foot ulcer.
- Peripheral neuropathy in this diabetic patient puts him at risk for the development of the necrotic ulcer on the lateral aspect of the great tow.
- Peripheral neuropathy decreases the patients’ ability to sense ulcers, calluses or abrasions that occur on their feet and put them at risk for wounds and infection.
dx diabetic foot ulcer
•Clinical recognition is diagnostic. Diabetic ulcers may be surrounded by a ring of callus, known as a “button abscess,” that is fluctuant to the touch but may extend deep to the joint and bone causing osteomyelitis.
tx diabetic foot ulcer
•Prevention is the best treatment for diabetic neuropathy and this can be accomplished with strict glycemic control and annual diabetic foot exams.
what is this?
- erythema, scaling, and bulla formation between the patient’s toes indicates interdigital type
- Tinea Pedis. Tinea pedis is a dermatophytic infection that often provides breaks in the integrity of the epidermis
- breaks provide an avenue in which bacteria can invade causing localized or spreading infections such as cellulitis or lymphangitis.
dx tx tinea pedis
•Diagnositc work-up: Clinical diagnosis is usually adequate. Fungal hyphae may be present on KOH preparation, but are often difficult to isolate. Treatment: Burrow’s wet dressings and Castellani’s paint are indicated for acute type infection, while aluminum chloride hexahydrate 20% may be used for chronic type interdigital tinea pedis. The use of shower shoes while bathing and washing feet with benzoyl peroxide bar directly after showering can help prevent future outbreaks of infection.
What is this?
HIV warts of the feet.
•HIV positive male patient presents with severe large verrucae vulgaris on the dorsum of the great toe. warts are extremely common, affecting 20% of school-aged childen, and also tend to occur in immunocompromised patients where they can be quite disfiguring. characterized by “black-dots” or thrombosed capillaries which are pathognomonic and uncovered by scraping the lesion with a scalpel. • In this case these warts were recalcitrant to salicylic acid preparations and required liquid nitrogen (LN2) over several visits.
What is this?
Ichtyosis •Only males are involved •Sex-linked recessive •Begin at birth and persist though life •AKA- fish skin
What is this?
•Clinical description: A bulla which arose as a localized reaction to a bite by a bedbug, Cemix lenticularis
