Week 3: Derm Flashcards
The skin has 2 layers:
- Epidermis
2. Dermis
The epidermis is the:
Outer highly differentiated later.
The dermis is the:
Inner supportive layer
Melanin is found in what layer?
The epidermis
The epidermis has 2 layers:
- Stratum corneum- outer horny layer
2. Cellular stratum
The outer horny layer of the epidermis is:
A layer of dead keratinized cells and is the derivation of skin color.
The dermis is made up of:
Connective tissue or collagen,elastic tissue, sensory nerve fibers, blood vessels, sebaceous glands, and hair follicles.
Epidermal appendages include:
Hair
Sebaceous glands
Sweat glands
Nails
Types of sweat glands:
Eccrine
Apocrine
Type of sweat gland that opens directly onto the surface of the skin and regulates body temperature through water secretion.
Eccrine
This is formed by epidermal cells that invaginate into the dermal layers.
Hair
Type of hair that is short, fine, and nonpigmented:
Vellus
Type of hair that is coarser, longer, thicker, and usually pigmented:
Terminal
These secrete sebum and are under control of sex hormones (primarily testosterone).
Sebaceous
Sebum in the newborn:
Holds water in the skin, is present for the few weeks of life and produces milia and seborrheic dermatitis (cradle cap).
When do eccrine sweat glands secrete in response to heat in infants?
Do not start to secrete until the first few months of life and then only minimally throughout childhood.
Questions to ask for subjective data r/t derm:
Past hx of skin disease, allergies, hives, psoriasis, or eczema?
Change in color?
Change is mole size, shape, color, and tenderness?
Itching?
Bruising?
Rash or lesions?
Medications?
What is the most common of skin symptoms?
Pruritus
Angle of nail base should be:
About 160 degrees
Abcde rule to detect suspicious lesions:
A- asymmetry B- border C- color D- diameter E- elevation and enlargement
What type of microscopic examination of skin scrapings can be used to examine for fungal disorders (hyphae or spores)?
Potassium hydroxide (KOH)
Round lesions:
Annular or circular
Lesions that flow/come together:
Confluent
Lesions that do not become blended:
Discrete
Lesions that cluster together:
Grouped
Lesions that are whirling in a circle:
Gyrate
Lesions in concentric rings:
Target or iris
Lesions that are in a line:
Linear
Lesions that are merged circles:
Polycyclic
Lesions that are band-like, unilateral, and are located along the cutaneous distribution of dermatome:
Zosteriform
A macule is:
Solely color change, flat and circumscribed
Less than 1 cm*
Examples of a macule:
Freckles, flat nevi, hypopigmentation, petechiae, measles, scarlet fever
What is a Papule?
Something you can feel, less than 1 cm caused by superficial thickening in the epidermis
Examples of a papule:
Elevated nevus, lichen planus, molluscum, wart (verruca)
What is a patch?
Macules that are larger than 1 cm
Examples of a patch:
Mongolian spit, vitiligo, cafe au lait spot, chloasma, measles rash
What is a plaque?
Papules that coalesce to form surface elevation wider than 1 cm
Examples of a plaque?
Psoriasis, lichen planus
What is a nodule?
Solid, elevated, hard or soft, and larger than 1 cm. May extend deeper into dermis than a papule
Examples of a nodule:
Xanthoma, fibroma, intradermal nevi
What is a wheal?
Superficial, raised, transient, and erythematous. Slightly irregular in shape due to edema.
Examples of a wheal:
Mosquito bite, allergic reaction, dermographism
Secondary skin lesions:
Crusts Scales Fissures Erosions Ulcers Excoriation Scar Lichenification Keloids
Common contagious bacterial infection of the superficial layers of the skin.
Impetigo
2 forms of impetigo:
Nonbullous with honey-colored crusts on the lesions
Bullous
What causes impetigo?
Group A strep
Staph aureus
MRSA
Bullous impetigo lesions are most common:
On the face, neck, hands, extremities, and perineum
Treatment of impetigo that is mild, localized, and nonbullous:
Mupirocin*
Retapamulin
Treatment of impetigo that has multiple lesions, nonbullous with infection in multiple family members, childcare groups, and in athletes:
Oral antibiotics
Treat for both s aureus and strep pyrogenes bc coexistence is common
Oral antibiotics for impetigo:
1st line: cephalexin 40mg/kg/day x 10 days
2nd line: augmentin 90mg/kg/day x 10 days (GI upset)
Complications of impetigo:
Lymphangitis, guttate psoriasis, erythema multiforme, scarlet fever, glomerulonephritis following strep.
Acute rheumatic fever- rare- caused by strep.
What is the testing for fungal infections?
KOH
Fungal infection of the skin or mucous membrane:
Yeast infection or thrush
Causative agent for candidiasis:
Candida albicans
Candidiasis is most common in:
Infants, obese children, adolescents, and the chronically ill or immunocompromised children
History of person with candidiasis will often include:
Recent antibiotic or steroid use over the previous weeks and occurrence of a rash in a moist, warm area.
Symptoms include friable, adherent white plaques on an erythematous base on the mucus membranes:
Thrush
Symptoms include cracked lips:
Cheilitis
Symptoms include fissured and inflamed corners of the mouth:
Angular cheilitis
Symptoms include bright erythema in flexural folds:
Candidiasis in the intertriginous areas (neck, axillae, or groin)
Moist, beefy red macules and papules with sharply marked borders and satellite lesions. Erosions May also be present:
Candidiasis of the diaper area
Diagnostic study for candidiasis:
KOH-treated scrapings of satellite lesions or mucosa reveal yeast cells and pseudohyphae.
Ringworm of the scalp:
Tinea capitis
Causative agents for tinea capitis:
Trichophyton tonsurans
Microsporum canis
Clinical findings of tinea capitis:
Diffuse fine scaling without obvious hair breaks and with subtle to significant hair loss.
Discrete areas of hair loss with stubs of broken hairs (black dot ringworm)
Classic patchy hair loss and scaly lesions with raised borders.
Scaly pustular lesions or kerions
Diagnostic studies for tinea capitis:
Woods light fluoresces yellow-green (positive with M. Canis)
KOH exam of scraped hair.
Fungal culture of completely plucked hair with root.
Tinea capitis management:
Topical antifungals as ineffective**
Griseofulvin ultramicrosize at 5 to 15 mg/kg/day once or twice daily or griseofulvin microsize at 20-25 mg/kg/day for 6-8 weeks.
- take with fatty food to enhance absorption
- treatment should be continued until clinical and mycologic cure
Shampoo with selenium sulfide 2.5% or econazole or ketoconazole 2% (2-3 times per week for 4 weeks) to decrease spore viability and keep other family members from being infected.
Can give prednisone 1-2 mg/kg/day for 5-14 days if long-standing kerion are present with inflammation.
Superficial fungal skin infection found on the nonhairy skin of the body:
Tinea corporis
Causative agents of tinea corporis:
M. Canis
Trich rubrum
Trich tonsurans
Classical appearance of lesions of tinea corporis:
Annular, oval, or circinate with one or more flat, scaling, mildly erythematous circular patches or plaques with red, scaly borders.
Diagnostic study for tinea corporis:
KOH treated scrapings of the border of the lesion reveal hyphae and spores
Fungal culture
What combination should be avoided in a tinea corporis case:
Antifungal/steroid combo as it makes infection worse
Management of superficial or localized tinea corporis infection:
Topical antifungal like miconazole or clotrimazole
Education of tinea corporis management:
Apply antifungal cream to the lesion including a zone of normal skin twice a day until clinical resolution which can take 1-4 weeks
Superficial fungal infection that tends to be persistent and occurs predominantly on the trunk. Lesions do not tan in the summer and become relatively darker in the winter.
Tinea versicolor (pityriasis versicolor)
Causative agent in tinea versicolor:
Yeast like organism, malassezia furfur (referred to as pityrosporum orbiculare and P. Ovale)
Tinea versicolor clinical findings:
Multiple, annular, scaling, discrete macules or patches, ranging from hypopigmented in dark-skinned (salmon-colored to brown) in light skinned individuals that are seen on the neck, upper back and arms, chest midline, and face (especially in kids).
Tinea versicolor diagnostic study:
KOH scrapings, though not necessary, reveal short curved hyphae and circular spores (spaghetti and meatballs).
Tinea versicolor management:
Selenium sulfide 2.5% lotion or 1% shampoo applied in a thin layer from face to knees for 30 minutes daily for a week followed by monthly applications for 3 months to help prevent recurrences.
Resistant or severe cases of tinea versicolor in older adolescents sometimes require:
Oral antifungal treatment with ketoconazole, fluconazole, or itraconazole
Patient education with tinea versicolor:
Sun exposure makes lesions appear hypopigmented
Repigmentation takes several months
If on oral antifungal encourage exercise bc sweating may enhance concentration of med in the skin.
Skin irritation occurs with overnight application
Absence of flaking when scraped is a sign of effective treatment
A benign childhood viral skin infection with little health risk that often disappears on its own in a few weeks to months and is not easily treated:
Molluscum contagiosum
Causative agent of molluscum contagiosum:
Poxvirus
Clinical findings of molluscum contagiosum:
Pruritus
Very small, firm, pink to flesh-colored discrete papules 1-6 mm in size
Surrounding dermatitis
Common areas: face, axillae, antecubital area, trunk, popliteal fossae, crural area was
Management of molluscum contagiosum:
Mechanical removal of the central core is to prevent spread and autoinoculation but is painful.
Topical meds may be beneficial:
Liquid nitrogen (painful)
Trichloroacetic acid
Etc
Pediculosis management:
Permethrin or pyrethrum plus piperonyl butoxide is first step.
2nd: remove nits
3rd: environmental cleanse
Acute or chronic inflammation resulting from a hypersensitive reaction to a substance, either and irritant or allergen
Contact dermatitis
Symptoms of contact dermatitis:
Chafed appearance with shiny, mild to severely erythematous, peeling, or dry, fissured skin
Red patches and plaques with secondary scales-irritant
Goal of treatment for contact dermatitis:
Appropriate skin care
Recognize and eliminate offending agents
Treat inflammation
Management of vesicular rash in contact dermatitis:
Burrow solution soaks or oatmeal baths and cool compresses (1tsp salt/pint of water) applied for 20 minutes every 4-6 hours.
What should not be used with inflammation in contact dermatitis?
Lanolin and petrolatum based emollients
Management of contact dermatitis:
Topical corticosteroids used 2-3 times daily will give relief in 2-3 days with complete healing in 2-3 weeks
Oral AH for itching
Management of lip licker dermatitis:
Emollients lotions and petroleum based emollients.
Do not use flavored lip creams
Chronic inflammatory dermatitis commonly called cradle cap in infants and dandruff in older adolescents.
Seborrhea
Causative agent of seborrhea:
Overproduction of sebum.
Overgrowth of M. ovalis
Seborrhea is not:
Pruritic and has no pustules
Seborrhea management:
Antifungal: azoles, selenium sulfide
Anti inflammatory: topical steroids, topical calcineurin inhibitors
Keratolytic (remove scales) topical salicylic acid
Alternative: tar based or tea tree oil
A common, mild, self-limiting papulosquamous disease caused by herpes virus 6 or 7. It is mildly contagious and occurs most commonly in the fall, early winter, and spring in temperate climates.
Pityriasis rosea
Symptoms of pityriasis rosea:
Prodrome of mild symptoms including malaise, pharyngitis, lymphadenopathy, and ha before onset of rash.
Herald patch: solitary, ovoid, slightly erythematous lesion with a fairly scaled slightly elevated border that enlarges quickly with central clearing and is most commonly found on the trunk, upper arm neck, or thigh
Diagnostic study for pityriasis rosea:
KOH preparation of a skin scraping is done to r/o tinea. Pityriasis is viral.
