Dermatology_UW Flashcards
What kind of reaction is allergic contact dermatitis
Type 4 hypersensitivity reactions
Comedones are present in rosacea or acne vulgaris?
Acne vulgaris
Presentation of rosacea. Demographics of patients?
Rosy flushing with telangectasia over cheese, nose and chin. May also have papules and pustules (that are not present in SLE, seborrheic dermatitis). Usually 30-60 year olds in fair skin, light hair and eye color.
Rosacea is preciptated by?
Hot drinks, heat, emotion and other causes of rapid body temperature changes.
What is the most frequently prescribed initiial therapy for rosacea?
Topical antibiotic such as metronidazole
Dry rough skin with horny plates over extensor surfaces is hallmark of?
Icthyosis. Worsens during winter. Sometimes called “lizard skin.”
What is the basic pathophysiological mechanism for GVHD?
Recognition of host major and minor HLA-antigens by donor T lymphocytes and consequent cell-mediated immune response.
What are the target organs in GVHD and the ppt?
Skin (maculopapular rash involving palms, soles and face that may generalize), intestine (blood-positive diarrhea), and liver (abnormal liver function tests and jaundice).
Ppt of tinea corporis
Ring-shaped scaly patches with central clearing and distinct borders.
Tx of tinea corporis.
Topical treatment with 2% antifungal lotions and creams (eg. Terbinafine) or systemic tx with griseofulvin for extensive disease.
Ppt of pityriasis rosea
Numerous oval, scaly plaques which follow trunk cleavage lines. Centers of lesions of crinkled, cigarette paper like appearance. Often presents with initital lesion called the herald patch which is much larger than the later lesions. Christmas tree distribution.
Erythema multiforme usually a/w what infection?
HSV infection
What is the clinical ppt of herpetic whitlow
Throbbing pain in distal pulp space, swollen, soft and maybe tender. Lateral nailfold may also be affected. Systemic sx like fever and lymphadenopthy may occur. Non-purulent vesicles on the volar aspect are clinically diagnostic. Usually self liming infection.
Herpetic whitlow caused by? Mode of transmission
HSV 1 or 2. Direct inoculation through broken skin.
How to dx herpetic whitlow
Positive hx of exposure and giant multinucleated cells in Tzanck smear.
Herpetic whitlow most commonly found in what population?
Women with genital herpes, children with herpetic gingivostomatits, health care workers are at increased risk due to exposure to infected saliva.
What is felon? Who develops it?
Bacterial infection o the distal volar space, characterized by throbbing pain and tense abscess. Tailors get it from needle injuries.
Acanthosis
Thickening of epidermis
Hyperkeratosis
Thickening of stratum corneum
Parakeratosis
Retention of nuclei in stratum corneum
Dyskeratosis
Abnormal keratinization
What is the ppt of warfarin induced skin necrosis? What areas are most commonly involved?
Pain, followed by bullae formation and skin necrosis. Breasts, buttocks, thighs and abdomen. Usually starts within weeks after starting therapy.
What is the management of warfarin-induced skin necrosis
Vitamin K should be administered promptly in early stages and if lesion progressions, d/c warfarin. Heparin should be used to maintain anticoagulation.
What is hidradenitis supparativa? How is it dxed?
Chronic inflammatory occlusion of skin follicles that occurs mostly in intertriginous areas but can also occur in hair bearing areas. Likely due to inability of keratinoctyes being able to shed from eptihelium properly. Clinically without biopsy.
Pathophysiology of hidradenitis suppurativa?
Initial solitary and painful inflamed nodule => lasts several days months => form abscess that can drain to skin surface with prurulent or serosanguineous material => typically improves after drainage. Multiple nodules can develop can lead to sinus tracts, comedones, significant scarring. Severe scarring in axilla can lead to linear rope like bands with decreased mobility and significant lymphadema
Intertrigo typically caused by?
Candida. Well defined erythematous plaques with satellite vesicles or pustules in intertriginous areas and occluded skin. Does not usually follow chronic course.
Seborrheic dermatitis can be found in people of all ages but is found with increased frequency in?
Parkinsons and HIV patients.
Which acne prescriptions cause phototoxic drug eruptions?
Of the tetracyclines - doxycycline is the most photosensitizing drug. Eruptions appear as exaggerated sun burns.
How does dermatitis herpetiformis present? What disease is it a/w?
Erythematous papules, vesicles, bullae occur bilaterally, symmetrically, and in grouped “herpetiform” arrangement on buttocks, extensor surfaces, elbows, knees, upper back. Celiac disease.
What is the tx for dermatitis herpetiformis.
Gluten free diet and dapsone. Clearance after dapsone is considered diagnostic.
Molluscum contagiosum occurs anywhere except?
Palms and soles.
Condyloma acuminata are caused by? Which serotypes are a/w WCC?
they are verrucous, papilloform lesions on anogenital area. HPV. 16 and 18 serotypes.
Presentation of scabies.
Intensely pruritic rash in the flexor surfaces of wrist, lateral surfaces of fingers, finger webs. Patients present with excoriations and small crusted red papules scattered around the affected areas. Classically make burrows.
What is the pathophysiology of scabies and how is it spread?
Due to Sarcoptes scabeiei mite. Rash due to delayed type 4 hypersensitivity reaction to the mite (feces and eggs). Spread through direct human to human transmission.
How is scabies diagnosed?
Skin scrapings from lesions revealing mites, ova and feces under light microscopy
How is scabies treated?
Topical permethrin cream 5% or oral ivermectin is preferred tx in adults.
Molluscum contagiosum is caused by what virus and what mode of transmission?
Poxvirus. Skin to skin transmission or contact with contaminated fomites. Often spread through sexual contact.
Molluscum is usually self-limited/contained in healthy adults but can cause more widepsread and prolonged illness in?
HIV patients and those with CD4 cell count of less than 100
For frostbite injuries, what is the best tx plan?
Rapid re-warming with warm WATER NOT WARM AIR (can cause more tissue damage). DO NOT evaluate for debridement until complete warming has been complete.
Cellulitis and purulent cellulitis caused by?
Streptococci and staph aureas repectively
What is the tx for cellulitis with systemic signs like rigors, malaise, fever, confusion?
IV nafcillin or cefazolin. In areas with high rates of MRSA, IV vancomycin.
For mild cellulitis (no systemic signs), what is the tx?
Oral dicloxacillin
What meds are given to patients with herpes zoster?
Antivirals like valacyclovir, acyclovir reduces the duration of symptoms and incidence of post-herpetic neuralgia.
What is senile purpura and what is it due to?
Ecchymosis that occurs in elderly patients in areas exposed to minor trauma (extensor surfaces for eg). Due to elastic fiber loss in perivascular connective tissue.
Vitiligo is due to what process and what is it a/w?
Due to autoimmune disease where melanocytes are attacked. A/w other autoimmune diseases like pernicious anemia, autoimmune thyroid disease, type 1 dm, primary adrenal insufficiency, hypopitutiarism, and alopecia areata.
Tinea veriscolor microscopic examination shows?
KOH prep. Spaghetti and meatballs appearance. Large blunt hyphae and thick budding spores.
Tinea veriscolor most commonly caused by?
Malassezia Globosa
Tinea versicolor treatment?
Topical tx with selenium sulfide or ketoconazole.
Steven Johnson syndrome is what kind of disease? What are the clinical features?
Hypersensitivity reaction to drugs, especially sulfonamides, NSAIDS, anticonvulsants and allopurinol. Coalescing erythematous macules, bullae, desquamation and mucositis. Systemic signs are common.
Epidermal inclusion cyst presents as?
Dome shaped, firm, freely movable cyst or nodule with small central punctum. It can remain stable or gradually increase in size but usually resolves spontaneously
Lipoma presentation
benign, painless subcutaneous mass with normal overlying epidermis. Unlike epidermal cysts, they are soft to rubbery and typically don’t regress and recur.
Tx for Comedomal acne, inflammatory acne and pustular acne
Comedomal: topical retinoids + salicyclic acid, glycolic acid. Inflammatory: mild+ topical retinoids + benzoyl peroxide, moderate: topical retinaoids + benzoyl peroxide + topical antibiotics like erythyromycn. Severe: above + oral antibiotics. Nodular (cystic): moderate topical retinoids + beonzyoyl peroxide + topical erythromycone, SEvere: add oral antiobiotics and refractory: oral isotretinoin
What is a chalazion? How should you approach a recurring chalazion?
Rubbery nodular lesion - chronic granulomatous condition that occurs when meimobian gland becomes obstructed. If recurs, do histopath exam to check if it’s sebacious carcinoma
Presentation of allergic contact dermiatitis
Type 4 hypersensitivity reaction. Presents day to weeks fter contact. Intensely pruritic erythematous rash with vesicles at site of exposure. Secondary infection as a result of excessive scratching can occur. Suggested by pus filled vesicles.
Erysipelas presentation and caused by?
Painful tender plaque, sharply demarcated. Caused by streptococcus pyogenes.
Acute urticaria etiologies
Infections (viral, bacterial, parasitic), IgE mediated (antibiotics, insect bites, food), direct mast cell activation (narcotics, muscle relaxers, radiocontrast medium), NSAIDs, idiopathic
Warts are typically caused by?
HPV
Warts look like?
Hyperkeratotic papules occur on soles of foot especially in young and immunocompromised people
