Dermatology Flashcards
What are the definitions of these terms? What are some examples of each?
Define vitiligo.
With what diseases is it associated?
skin depigmentation of unknown etiology, but patients often have antibodies to melanin, gastric parietal cells, and thyroid peroxidase
associated with autoimmune conditions such as
pernicious anemia
hypothyroidism
Addison disease
Type 1 diabetes
Name several conditions to consider in patients with pruritus
obstructive biliary disease
uremia
polycythemia rubra vera (classically after a warm shower or bath)
contact or atopic dermatitis
scabies
lichen planus
Define contact dermatitis - what type of hypersensitivity is it?
How do you recognize it?
What are the classic causes?
Type IV Hypersensitivity Reaction
look for new exposure to a classic offending agent (poison ivy, nickel, deodorant)
well-circumscribed rash in area of exposure
skin is red, itchy, and often with vesicles or bullae
Define atopic dermatitis.
What history points to this diagnosis?
What is the biggest problem that these people face?
Treatment?
what it is: chronic condition that begins in the first year of life with red, itchy, weeping skin on the head, upper extremities
clues: family and/or personal history of allergies (e.g., hay fever) and asthma
problem: scratching of affected skin, which leads to skin breaks and possible bacterial infection.
treatment: moisturizing creams, topical steroids, and immune modulating agents (topical pimecrolimus or tacrolimus).
Define seborrheic dermatitis.
What part of the body does it involve and how is it treated?
causes cradle cap and dandruff, as well as blepharitis (eyelid inflammation)
look for: scaling skin +/- erythema on the hairy areas of the head (scalp, eyebrows, eyelashes, mustache, beard), as well as on the forehead, nasolabial folds, external ear canals, and postauricular creases
treatment: dandruff shampoo (selenium or tar), topical corticosteroids, and/or ketoconazole cream.
Name the 5 dermatologic fungal infections.
- Tinea corporis (body/trunk): red ring-shaped lesions with raised borders that tend to clear centrally while expanding peripherally
- Tinea pedis (athlete’s foot): macerated, scaling web spaces between the toes that often itch; may be associated with thickened, distorted toenails (onychomycosis)
- Tinea unguium (onychomycosis): thickened, distorted nails with debris under the nail edges.
- Tinea capitis (scalp): common in children, scaly patches of hair loss; may have an inflamed, boggy granuloma of the scalp (known as a kerion) that usually resolves on its own
- Tinea cruris (jock itch): common in obese males; usually is found in the crural folds of the upper, inner thighs.
What 2 organisms cause fungal infections?
Trichophyton species
Microsporum species (common in tinea capitis; fluoresces under wood lamp)
How are fungal infections diagnosed and treated?
perform KOH prep and visualize under a microscope
- or -
culture the species
These infections are clinically common; thus empirical treatment is often done without a formal diagnosis; for USMLE testing, however, a formal diagnosis should be sought before treating.
Treatment: depends on the location/severity
- tinea capitis and onychomycosis: PO antifungals
- Rest: topical antifungals (imidazoles such as miconazole, clotrimazole, or ketoconazole)
- Severe or persistent infections: griseofulvin
True or false: Candidiasis is often a normal finding in women and children
True
Oral thrush is common in children
Candida vulvovaginitis is common in normal women, esp during pregnancy or after antibiotics
However, during other periods and in different patients, candidal infections may be a sign of diabetes or immunodeficiency: oral thrush in a man should make you think about AIDs, recurrent vulvovaginal candidiasis should prompt screening for diabetes.
How is candidiasis normally treated?
What if it’s extensive or resistant to standard treatments?
standard -> local/topical nystatin or imidazoles (miconazole, clotrimazole)
extensive or resistant disease –> Oral therapy (nystatin or ketoconazole)
What causes scabies?
How do you recognize it?
How do you diagnose and treat it?
Sarcoptes scabei
recognition: visible burrows, classically in the finger web spaces and flexor surface of the wrists; may also have severe pruritus, and scratching can lead to secondary bacterial infection.
dagnose: scrape a mite out of a burrow and view it under a microscope
treatment: permethrin cream (1st line) to the entire body of all contacts; lindane only if first line is not an option because it can cause neurotoxicity
How do you recognize and treat tinea versicolor?
aka pityriasis versicolor
is a Pityrosporum fungal infection that presents with patches of various size and color (brown, tan, and white) on the torso of young adults; often becomes noticeable in the summer because the affected areas fail to tan and appears white.
Diagnose from lesion scrapings (KOH prep).
Treat with selenium sulfide shampoo or topical imidazoles.
What causes lice? How are lice diagnosed and treated?
Lice (pediculosis) can involve the
- head (Pediculus capitis; common in school-aged children)
- body (Pediculus corporis; poor hygiene)
- pubic area (Phthirus pubis; transmitted sexually)
diagnose: seeing lice on hair shafts
treatment: permethrin cream (preferred over lindane because of lindane’s neurotoxicity), decontaminate sources (wash or sterilize combs, hats, bed sheets, clothing).
What causes warts?
How are they treated?
HPV 6/11
treatment: salicylic acid, liquid nitrogen, and curettage
Define molluscum contagiosum. How do you recognize it? How is it treated?
poxvirus infection - common in children but may also be transmitted sexually
skin colored, smooth, waxy papules with umbilicated center
treatment: freezing and curettage
True or false: A child with genital molluscum is probably a victim of sexual abuse.
False
most common mechanism: autoinoculation, in which the child has a lesion on the hand that spreads to the genital area from scratching
However, do not automatically assume child abuse, although it must be ruled out!
How is acne described in medical terms?
Why do they form?
What bacteria may be partially involved in its pathogenesis?
Blockage of pilosebaceous glands and Propionibacterium acnes
proper description: comedones, papules, pustules, inflamed nodules, superficial pus-filled cysts, inflammatory skin changes, scar formation
Define rosacea.
In what age group is it seen?
How do you treat it?
common skin condition that causes redness in your face and often produces small, red, pus-filled bump; often looks like acne; look for rhinophyma (bulbous red nose) and coexisting blepharitis (inflammation of the eyelids)
begins in middle age
numerous triggers: sun exposure, emotional stress, alcohol consumption, spicy foods, and hot weather.. Treat with topical metronidazole or oral tetracycline.
Give the classic description and natural course of pityriasis rosea.
Treatment?
typically seen in young adults
starts off as a herald patch (slightly erythematous, scaly, ring-shaped or oval patch classically seen on the trunk), followed 1 week later by itchy lesions on the back with a long axis that parallels the Langerhans skin cleavage lines, typically in a “Christmas tree” pattern.
Treatment: reassurance, since the condition usually remits spontaneously in 1 month.
What are the four Ps that confirm a diagnosis of lichen planus?
when do they tend to occur?
where are they usually found?
what are these folks at risk for?
Pruritic, purple, polygonal papules
adults
classically found on wrists, lower legs, or oral mucosa
at risk for oral cancer - therefore must monitor the oral lesions!
Describe the classic lesion of erythema multiforme.
What drugs classically cause it?
what is a sequelae of this?
target lesions
causes: sulfa, penicillin, herpes infections, idiopathic
Stevens-Johnson syndrome, a severe form of erythema multiforme, is often fatal because of severe, widespread skin involvement.
Describe the classic lesion of erythema nodosum.
With what diseases is it commonly associated?
tender, red nodules (due to inflammation of the subcutaneous tissue and skin), classically over the shins (pretibial)
etiologies: sarcoidosis, coccidioidomycosis, ulcerative colitis, infections (e.g., streptococcal, tuberculosis) and drugs (e.g., sulfonamides)
How is pemphigus vulgaris different from bullous pemphigoid in terms of:
presentation
IHC staining
treatment
pemphigus vulgaris
- due to IgG antibody to desmoglein 3 (associated with desmosomes), which causes a lace-like/fishnet immunoflorescence pattern
- presents with multiple flaccid bullae, starting in the oral mucosa and spreading to the skin of the rest of the body; (+) Nikolsky sign
- potentially life-threatening
- treatment: PO steroids
bullous pemphigoid
- due to IgG antibodies against BPAg1/2, results in a linear immunoflorescence pattern and (+) eosinophils
- presents with large, tense, and itchy bullae, (-) Nikolsky sign
- treatment: same/PO steroids
What skin disease is associated with celiac disease (gluten intolerance or sensitivity)?
What other symptoms are usually present?
How is it diagnosed and treated?
Dermatitis herpetiformis
- intensely pruritic vesicles, pap- ules, and wheals on the extensor aspects of the elbows and knees and possibly on the face or neck
- diarrhea and weight loss (caused by gluten sensitivity)
- diagnosis: skin biopsy - shows IgA deposits, test for celiac disease
- treatment: gluten free diet
How are decubitus ulcers staged?
Stage 1 - intact skin with nonblanchable redness of a localized area.
Stage 2 - partial thickness loss of the dermis presenting as a shallow open ulcer; may present as an intact or ruptured blister.
Stage 3 - full thickness tissue loss; subcutaneous fat may be visible, but bone, tendon, and muscle are not exposed.
Stage 4 - full thickness skin loss with exposed bone, tendon, or muscle.
An unstageable ulcer has full thickness loss in which the base of the ulcer is covered with slough or eschar. The true depth of the ulcer cannot be determined until the slough or eschar is removed
Why is keratoacanthoma of note?
How does it normally present?
Treatment?
can mimic skin cancer (especially squamous cell cancer)
usually presents as a a flesh-colored lesion with a central crater that contains keratinous material, classically on the face. Very rapid onset and grows to its full size in 1 to 2 months
lesion involutes spontaneously in a few months and requires no treatment.
When and where are keloids seen?
What populations does it usually affect?
How are keloids usually managed?
overgrowths of scar tissue after an injury, usually slightly pink and classically appear on the upper back, chest, and deltoid area
seen most frequently in black patients
management: steroids - do not excise these lesions because it may worsen scarring!
Describe the classic lesion of basal cell cancer. What should you do if you suspect it?
shiny papule with an umbilicated center that later may ulcerate and peripheral telangiectasias; usually on skin-exposed area (the head is classic)
treatment: biopsy and excision
From what 2 lesions does squamous cell cancer classically develop?
Management?
What is Bowen disease?
Actinic keratosis or burn scars
biopsy if there is evidence of nodularity, wart-like, or ulceration
Bowen’s disease: squamous cell carcinoma in situ
What type of melanoma do black patients tend to develop?
How do you recognize it?
acrolentiginous - look for black dots on the palms, soles or under the fingernails that start to change in appearance or cause symptoms
Describe Paget disease of the nipple. What is its significance?
a unilateral, red, oozing or crusting nipple in an adult woman that fails to respond to typical dermatology treatments
signifies an underlying breast cancer (usually invasive ductal carcinoma or DCIS) with extension to the skin.
Define stomatitis. What does it suggest?
what it is: inflammation of the mucous membranes of the mouth; fissuring of the corners of the mouth (angular stomatitis).
causes: deficiencies in B-complex vitamins (riboflavin/B2, niacin/B3, pyridoxine/B6) or vitamin C
