exam 1 - derm Flashcards
miliaria/heat rash
-Obstruction of eccrine sweat ducts
Superficial: Tiny (1-2 mm), superficial grouped vesicles without erythema over intertriginous areas and adjacent skin (neck/upper chest)
-Deep: Erythematous grouped papules called miliaria rubra
-Cooling is tx of choice
atopic dermatitis
-Pathogenesis
-Interaction among susceptibility genes, host environment, skin barrier defects, pharmacologic abnormalities, and immunologic response
-3 clinical phases
-1. Infantile eczema: Onset 2-3 months, ends at 18 months – 2 years
-Dermatitis on cheeks and scalp, oval patches on trunk
-Later involves extensor surfaces of extremities
-2. Childhood/flexural eczema: Onset 2 years, lasts through adolescence
-3. Adolescent eczema: Continuation of flexural eczema with hand/foot dermatitis
discoid annular eczema
mimics ring worm
atopic dermatitis: tx
-Acute Stages
-Medium-potency topical glucocorticoids (under wet dressings) -> Low-potency only for face and intertriginous areas
-Wet dressings: Wet underwear, cotton socks (several days x 1 week)
-Relief of itching: Oral antihistamines (cetirizine in AM, hydroxyzine in PM)
-Chronic Stages
-Treatment aimed at avoiding irritants and restoring moisture
-No soaps or harsh shampoos
-Bathing minimized to every second or third day
-Lubrication of skin
-Medium-potency topical steroids
-Superinfection > systemic abx x 10-14 days
-Topical immunosuppressive agents (tacrolimus/pimecrolimus) -> > 2 years of age, unresponsive to medium-potency steroids
-Narrow-band UV-B, twice weekly
-Systemic immunosuppressive (dipilumab/Dupixent) is the first biological therapy approved in patients 12 years or greater
atopic dermatitis: complications
-Dry, itchy skin
-Cracks in epidermal barrier (inability to hold water within stratum corneum > shrinking of layer)
-Ineffective barrier to entry of irritants
-Secondary infections with S. aureus and S. pyogenes
primary irritant contact dermatitis: diaper dermatitis
-Develops within several hours, peaks at 24 hours, then disappears
-Prolonged contact of skin with urine and feces (irritating chemicals – urea and intestinal enzymes)
-Erythema and scaling of the skin in the perineal area with sparing of inguinal folds
-In 80% of cases lasting > 3 days, affected area is colonized with C. albicans
-Beefy red, sharply demarcated dermatitis with satellite lesions
-Treatment
-Frequent diaper changes, washing area with clean cloth and water
-Air drying with diaper changes and prior to application of topicals
-Barrier creams with zinc oxide and imidazole cream BID
allergic contact dermatitis
-Delayed onset of 18 hours, peaks at 48-72 hours, lasts up to 2-3 weeks
-Plants such as poison ivy, poison sumac, and poison oak cause most cases in children
-Also, from nickel (earrings/belts), neomycin
-Blisters (linear), oozing, crusting
-Treatment:
-Localized: Potent topical corticosteroid
-Severe, generalized: Prednisone, 1-2 mg/kg/day, PO, x 10-14 days
viral exanthems: measles (rubeola)
-Highly contagious (droplet and airborne transmission), caused by single-stranded RNA paramyxovirus, with humans as only host
-Infects URT/regional lymph nodes > spreads systemically; secondary viremia (5-7 days) spread to respiratory tract, skin, and other organs
-Contagious from 1-2 days prior to onset of symptoms (5 days before – 4 days following appearance of rash)
-dont need to know^^^
-4 phases: Incubation (8-12 days from exposure to onset), prodromal (catarrhal), exanthematous (rash), and recovery
-3 day prodromal period: Cough, coryza, conjunctivitis and pathognomonic Koplik spots! (gray-white, sand-grain-sized dots on buccal mucosa, opposite lower molars)
-Conjunctiva with possible Stimson line! (transverse line of inflammation along the eyelid margin)
-Exanthematous phase: Sx + FEVER
-Macular rash, spreading from HEAD TO TOE over 24 hours; rash fades in the same pattern
-Generalized lymphadenopathy (cervical nodes most prominent)
-AOM, PNA, and diarrhea common in infants
viral exanthems: measles (rubeola): dx and tx
-dx:
-Serologic testing for IgM antibodies (appear 1-2 days into rash, persist for 1-2 months)
-+/- genetic testing -> RT-PCR
-Suspect cases reported immediately to local/state health department
-Treatment:
-Supportive care – fluids, antipyretics
-WHO recommends routine administration of vitamin A x 2 days to children with acute measles
viral exanthems: rubella (german/3-day measles)
-Caused by single-stranded RNA togavirus, humans only host
-Invades respiratory tract > dissemination (primary viremia) > replication in reticuloendothelial system > secondary viremia, virus present in peripheral blood monocytes, CSF, and urine
-Spread through direct or droplet contact with NP secretions (2 days before or 5-7 days after rash onset)
-dont need to know^^^
-Incubation period 16-18 days, mild catarrhal symptoms
-Retroauricular, posterior cervical, and posterior occipital lymphadenopathy with erythematous, maculopapular, discrete rash
-Rash spreads from head to toe, lasts for 3 days
-Rose-colored spots (Forchheimer spots) on soft palate may appear before rash
-Other symptoms: Pharyngitis, conjunctivitis, anorexia, headache, malaise, low-grade fever, polyarthritis, parasthesias, tendonitis
-Dx:
-Serologic testing for IgM antibodies (positive 5 days after onset) or by 4-fold or greater increase in specific IgG antibodies in acute/convalescent sera
-Treatment: Supportive
viral exanthems: erythema infectiosum (5th ds)
-Caused by single-stranded DNA virus, parvovirus B19!!
-Viral affinity for RBC progenitor cells -> aplastic crisis in pts with hemolytic anemias (SCD, spherocytosis, and thalassemia)!!!
-Incubation period typically 4-14 days
-Begins with mild illness characterized by fever, malaise, myalgias, and headache > rash 7-10 days later
-3 stages of rash:
-1. Initially: “Slapped cheek” rash with circumoral pallor
-2. 1-4 days later: Erythematous, symmetric, maculopapular, truncal rash
-3. Central clearing of rash takes place, distinct lacy!, reticulated! rash
-Rash may be pruritic, does not desquamate
-Adolescents/adults may experience myalgia, significant athralgias/arthritis, headache, pharyngitis, coryza, and GI upset
-May cause hepatitis, myocarditis, and papular-purpuric gloves and socks syndrome
-Transient aplastic crisis (SCD): Fever, lethargy, malaise, pallor, headache, GI symptoms, respiratory symptoms
-Extremely low reticulocyte count, low hemoglobin, transient neutropenia/thrombocytopenia
viral exanthems: erythema infectiosum (5ths ds): dx and tx
-Diagnosis
-Hematologic abnormalities: Reticulocytopenia x 7-10 days, mild anemia, thrombocytopenia, lymphopenia, and neutropenia
-Detected by PCR and electron microscopy of erythroid precursors in bone marrow
-Serologic testing (IgM antibodies) is diagnostic (detects infection within prior 2-4 months)
-Treatment: Supportive care, transfusion (aplastic crisis), IVIG for immunocompromised
viral exanthems: roseola infantum (exanthem subitum, 6th ds)
-Caused by double-stranded DNA virus, human herpesvirus type 6 (HHV-6) in most cases (HHV-7 in 10-30% of cases)
-Major cause of acute febrile illnesses in infants and may be responsible for up to 20% of ER visits for children 6-18 months of age
-High fever!!! (> 40C) with abrupt onset, lasts 3-5 days > giving way to maculopapular, rose-colored rash (lasts 1-3 days)
-URI symptoms, erythematous TMs, and cough
-Dx: PCR for detection of HHV-6 in blood (does not differentiate latent, reactivation, or primary infections)
Treatment: Supportive
viral exanthems: varicella-zoster (chickenpox/zoster)
-Caused by double-stranded DNA virus, varicella-zoster virus (VZV)
-Chickenpox (varicella) is primary infection
-Transmission via direct contact, droplet, and air
-Infects via conjunctivae or respiratory tract and replicates in NP and URT
-Primary viremia -> infects regional lymph nodes, liver, spleen, and other organs
-Secondary viremia -> cutaneous infection with typical vesicular rash
-Communicability from 2 days prior to 7 days after onset of rash (when all lesions are crusted)
-Resolution of chickenpox -> virus persists in dorsal root ganglia
-Zoster (shingles) is reactivated latent infection
-Transmission via direct contact
varicella-zoster sx
-Incubation period is generally 14-16 days
-Prodromal symptoms of fever, malaise, and anorexia may precede rash by 1 day
-Rash progression:
-Small red papules -> nonumbilicated, oval, tear-drop-like vesicles on an erythematous base -> vesicles ulcerate, crust, and heal
-New crops appear for 3-4 days
-Usually begins on trunk followed by the head, face, and extremities (rare)
-All forms of lesions are present at same time
-Marked pruritis
-Pre-eruption phase: Intense, localized, burning pain and tenderness (acute neuritis) along a dermatome, accompanied by malaise and fever
-Rash progression:
-Several days later, eruption of papules -> vesiculation (in dermatomal distribution/unilateral) -> crusting/healing
-Thoracic and lumbar regions MC
-CN V involvement: Corneal/intraoral lesions
-CN VII involvement: Ramsay Hunt Syndrome –facial paralysis and ear canal vesicles
-Postherpetic neuralgia: Pain persisting > 1 month is uncommon
varicella-zoster: dx and tx
-dx- PCR of vesicular fluid is method of choice
-Treatment (Varicella)
-Symptomatic: Anti-pyretics, cool baths, and careful hygiene
-Acyclovir (all age groups), valacyclovir (2 years and older)
-Not recommended in otherwise healthy children
-Early (within 24 hours of rash onset) in immunocompromised patients is effective in preventing PNA, encephalitis, and death
-Treatment (Zoster)
-Acyclovir, valacyclovir, famciclovir (adults)
-Accelerates cutaneous healing, hastens resolution of acute neuritis, and reduces risk of postherpetic neuralgia
viral exanthems: coxsackie (hand-foot-mouth ds)
-Caused by coxsackieviruses, especially types A5, A10, and A16
-Mild fever, sore throat, and malaise
-Rash:
-Vesicles/red papules found on pharyngeal pillars, tongue, oral mucosa, hands (palms), and feet (soles)
-Lesions may last 1-2 weeks
-soft palate tiny red spots
-nails are peeling 1-2 months after
-swab for strep jic
-Treatment: Supportive
irritant dermatits vs candidal/fungal dermatitis -> diaper rash
-if aquaphor doesnt work after 2-3 days -> go back to office -> prob fungal
-irritant- spares creases/skinfolds
-candidal/fungal- satelittle lesions, beefy
-doesnt spares the creases and folds
reactive erythemas: drug eruptions
-May produce urticarial, morbilliform, scarlatiniform, pustular, bullous, or fixed skin eruptions
-Most reactions begin 7-14 days after drug first administered and may continue for days after discontinuation
-Urticaria may appear within minutes
-tends to involve the hands and feet
-Treatment: Discontinuation of offending drug, anti-histamines prn
reactive erythemas: erythema multiforme
-Papules -> dark center -> lesions with central, bluish discoloration/blisters and characteristic target lesions (3 concentric circles of color change)
-Most cases precipitated by HSV
-wide spread targetoid rash
-Treatment:
-PO anti-histamines, systemic corticosteroids
-Most lesions last no more than 2 weeks
reactive erythemas: steven johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)
-Severe, life-threatening disorders
-Usually preceded by a prodrome of fever, malaise, and URI 1-14 days prior to onset of lesions
-Red macules coalesce into large patches (face/trunk) -> evolve rapidly into bullae/areas of necrosis
-SJS is epidermal detachment < 10% of body surface area; TEN > 30%
-Any mucosal surface can be involved (oral, ocular, urogenital, GI, trachea)
-MCC: NSAIDs, sulfonamides, anticonvulsants, and antibiotics
-Dx is clinical
-Mortality as high as 37% for severe TEN cases (sepsis)
-Treatment:
-Removal of offending agent
-Controlled clinical trials: IVIG, cyclosporine, etanercept
-Early interventions: Meticulous wound care, IV/NG feeding, monitoring I&Os and electrolyte status, early ophthalmology consult
