Dermatology Part 1 Flashcards
Define acanthosis nigricans.
Thickened, velvety, darkly pigmented plaques on the neck or axillae
What patients typically get acanthosis nigricans and what condition must be screened for when it is seen?
Common in obesity and diabetes –> must screen patents for DM when seen
What underlying condition may be present in a patient with acanthsis nigricancs?
Benign: obesity, drug-induced, DM, other endocrine disorders
Malignant: GI/GU malignancy, lymphoma
Define and describe acne vulgaris.
Open comedones (blackheads), closed comedones (whiteheads), papules and pustules on the face, neck, chest, and upper back.
In what patients is acne vulgaris most commonly seen and what is the most common causative organism?
Seen in adolescents.
Caused by propionibacterium acnes
What are the treatment options for acne vulgaris and what are any contraindications?
Mild: topical retinoids, topical abx, benzoyl peroxide
Moderate: add PO abx
Severe: isotretinoin - CI in pregnancy –> must use two forms of birth control
Define and describe actinic keratosis.
Patient will c/o rough bumps on the head with a PE that shows rough, scaly, erythematous papules on sun-exposed areas.
What patients get actnic keratosis and what condition must be investigated when seen?
Seen in men only, usually with an outdoor occupation or other Hx of sun exposure. May progress to squamous cell carcinoma.
What are the risk factors for developing actinic keratosis?
Sun exposure, fair skin
Define and describe alopecia areata.
Patches of smooth, non-scarring hair loss with patches of smaller hairs termed exclamation hairs
What is the most common cause of alopecia areata and what is the treatment?
Cause: autoimmune
Treatment: intralesional corticosteroids
Define and describe basal cell carcinoma.
Pearly papule with rolled borders and telangiectasia seen on the face, ears, or neck.
How is the diagnosis of basal cell carcinoma made and what is the treatment?
Dx: shave biopsy
Tx: surgical excision
T/F: Basal cell carcinoma is rare, but has a high mortality rate because it commonly metastasizes before being diagnosed.
False: It is the most common form of skin cancer, but rarely metastasizes.
Define and describe bullous pemphigoid.
Patient will c/o intensely pruritic papules that became large, tense blisters with a PE that shows tense firm blisters that do not extend with lateral pressure.
Define Nikolsky sign and state its significance relative to bullous pemphigoid.
NS: lateral pressure applied to the lesion causes it to sheer away from the underlying healthy epidermal layers. This is NOT present in bullous pemphigoid.
List the most common patient population, cause, and treatment for bullous pemphigoid.
Pop: patients > age 60
Cause: autoimmune
Treatment: corticosteroids and immunosuppressants
Define and describe cellulitis.
Patient c/o pain, redness, and swelling with a PE that shows tenderness, erythema with poorly demarcated borders, and lymphedema.
State the treatment and most common causative organisms of cellulitis.
Cause: staph and strep
Tx: Bactrim, doxycycline, linezolid –> admit to hospital if no improvement in 48 hours.
Describe condyloma acuminata
painless, cauliflower-like lesion on genitals.
What is the most common causative agent of condyloma acuminata and what condition must be considered when seen?
Cause: HPV 6 and 11 –> strong association with DU and rectal cancer
What comorbid conditions are commonly present in patients with atopic dermatitis?
Asthma and/or hay fever
Describe the common S/S of patents with atopic dermatitis.
Itchy, scaly rash that is worse in winter. PE will show thick, leathery, hyperpigmented areas - especially on flexor surfaces.
Differentiate the location of PE findings in atopic dermatitis in infants versus those in children and adults.
Infants: face and extensor surfaces of extremities
Kids/adults: flexor surface of the extremities –> face is less commonly involved.
What sequelae are patients with atopic dermatitis particularly susceptible to?
Compromised skin integrity leading to infections
Describe the skin findings associated with seborrheic dermatitis.
Superficial scales that are typically greasy and yellow.
In what patients is seborrheic dermatitis most common and where are the skin findings typically found?
Pediatrics –> scalp, central face, preauricular skin, and intertrigenous areas (skin folds
Describe the physical exam findings associated with perioral dermatitis.
irregularly grouped, discrete red papulopustules on a red base on the face, but spare the vermilion
border (the line just above upper lip)
In what patients will perioral dermatitis be seen?
Women age 16 - 45
What is the treatment for perioral dermatitis?
metronidazole and erythromycin
Describe the skin findings of dermatitis herpeteformis.
Multiple intensely pruritic papules and vesicles that occur in grouped arrangements
In what comorbid conditions is dermatitis herpeteformis commonly seen?
Most common = celiac.
Other = thyroid disease
What is the treatment for dermatitis herpeteformis?
Dapsone and a gluten free diet
What are the most common causes of allergic dermatitis?
Nickel, poison ivy, soaps, clothing
What type of hypersensitivity reaction is allergic dermatitis?
Type IV
How is allergic dermatitis diagnosed and how is it treated?
Dx: patch test
Tx: topical steroids, PO steroids if severe –> typically will resolve spontaneously in 1 - 3 weeks
What is the hallmark sign of a drug eruption?
Rash recurs in the same location each time the drug is used.
What medications are most commonly responsible for drug eruptions?
Bactrim, tetracyclines, penicillins, quinolones, dapsone, NSAIDs, Tylenol, bartiturates, antimalarials
What are the common S/S associated with dyshidrotic eczema?
Vesicles that appear to contain grains of tapioca and intense itching on the palms and sides of the fingers.
Describe the S/S associated with eryspilas.
Deeply erythematous, sharply demarcated elevated shiny patch with fever, malaise, chills, nausea.
What is typically the causative organism of eryspilas and what is the treatment?
Cause: Strep pyogenes
Tx: PCN, amoxicillin, azithromycin, or clarithromycin
Describe the S/S associated with erythema mutiforme.
Target-like lesions with a central dark papule surrounded by a pale area and a halo of erythema found mostly on the palms and soles.
What conditions typically manifest erythema multiforme?
HSV
What drugs commonly elicit the development of erythema multiforme?
SOAPS –> Sulfa drugs, Oral hyperglycemics, Anticonvulsants Penicillin, nSaids
Differentiate erythema multiforme minor and major.
Major involves the mucus membranes
What infections most commonly cause viral exanthems (rash)?
Varicella, erythema infectiosum, roseola, measles (rubeola), rubella
Define folliculitis and state the most common infectious cause.
Inflammation of the hair follicles –> Staph aureus
Describe S/S associated with folliculitis.
Erythematous papules/pustules, usually not painful. Abscess may form in more severe cases.
What is the treatment of folliculitis?
1: gentle cleansing and mild compresses –> keep dry
2: Topical clindamycin or erythromycin if infectious
3: PO abx in severe cases
What areas of the body are likely to have a non-infectious folliculitis?
Warm, oily areas
What is usually the causative agent in hot tub folliculitis?
Pseudomonas
How is hot tub follicuitis treated?
Usually self-limiting. May use topical cream or PO cipro in severe/persistent cases.
What are the common S/S associated with HSV?
Painful vesicles with erythematous base and erosions on the tongue, buccal mucosa, and lips.
What lab test is used to diagnose HSV and what is the finding?
Multinucleated giant cells on Tzanck smear, but Dx is usually clinical.
What is the most common causative agent of oral herpes and what is the treatment?
HSV-1 –> topical antivirals or PO acyclovir
In what type of patient will hidradenitis suppurativa be seen?
Women with Hx of lesions that have waxed and waned over past few years.
Describe the common S/S associated with hidradenitis suppurativa.
Tender nodules in her axillae and anogenital area where apocrine sweat glands are present. Lesions will often be malodorous with exudative drainage.
What is the treatment for hidradenitis suppurativa?
intralesional triamcinolone, topical clindamycin
What system is used to grade severity of hidradenitis suppurativa?
Hurley staging system
What is the typical modality leading to histamine poisoning and what is the treatment?
Ingestion of dark fleshed, peppery tasting fish –> tuna, mahi-mahi, mackerel. Tx with antihistamines.
Describe the 4 types of hypersensitivity reactions.
1: IgE degranulation of mast cells –> anaphylaxis, urticaria, angioedema –> requires prior exposure
2: IgG/M reaction with complement activation –> requires prior exposure.
3: IgG mediated with complement activation –> SLE, RA, serum sickness
4: T-cell activation against surface antigens –> contact dermatitis, transplant rejection, PPD skin test
In what population is impetigo typoclaly seen and what is the causative organism?
Children ages 2-5 –> staph aureus and group A strep
What are the risk factors for impetigo?
warm, humid conditions, poverty, crowding, and poor hygiene –> secondary impetigo can occur at sites of minor abrasions.
Describe the S/S associated with impetigo.
Begins as papules that progress to vesicles and surrounding erythema. The vesicles eventually rupture and form a thick, adherent, golden crust. Regional lymphadenopathy is also a common finding.
How is impetigo typically diagnosed?
Clinical but gram stain and culture to ID pathogen
What is the treatment for impetigo?
Topical mupirocin or PO cephalexin if widespread
If MRSA –> doxycycline, clindamycin, or Bactrim
How soon can children with impetigo return to school?
24 hours after starting abx
In what patients is Kaposi’s sarcoma seen and what is the most common causative agent?
AIDS patients (CD4 < 200) Caused by HHV-8
What are the classic findings in Lichen Planus?
Four P’s –> Papules that are Pruritic, Purple, and Polygonal. Will also have Wickham’s striae - fine, white lines.
What is the treatment of Lichen Planus?
Corticosteroids
Describe the S/S associated with Lichen Simplex Chronicus.
Multiple linear excoriations and thickened skin with generalized pruritis.
Describe the treatment for a lipoma.
Minimize rubbing and scratching –> excision is definitive.
