Derm Flashcards

Question

Exanthematous Drug Eruption definition, sx, dx, tx

Answer 1

Morbilliform or maculopapular drug eruption characterized by macules or small papules after the initiation of drug treatment MC occurs 5-14d after the initiation of the offending med or within 1-2d in previously sensitized individuals sx Latency (not previously sensitized): cutaneous eruption typically occurs within 7-10d after starting tx; for short courses of tx (e.g., antibiotics), the eruption may appear 2-4d AFTER stopping tx Cutaneous features: erythematous macules &/or papules; morbilliform (measles like), rubelliform (rubella like); predominantly involves trunk/proximal extremities *mild – acral sites often spared *severe – can involve face, palms/soles Systemic sxs (mild): pruritis, low-grade fever dx: clinical Labs: slightly elevated acute phase reactants, mild eosinophilia tx Prompt withdrawal of the offending med Symptomatic: oral antihistamines (H1 blockers) - second gen: cetirizine, loratadine, fexofenadine - first gen: diphenhydramine, hydroxyzine, chlorpheniramine Severe: short course of PO steroids

Answer 2

Self-limited, localized subcutaneous (or submucosal) swelling resulting from extravasation of fluid into the interstitium Affects the mucosal tissues of the face, lips, tongue, larynx, hands, feet, & genitalia sx Mast-cell (histamine) mediated (e.g., allergic rxns) *angioedema that may be accompanied w/ other allergic rxn sxs (urticaria, flushing, pruritis, bronchospasm, stridor, throat tightness, hypotension) dx If there is no information to suggest an external cause & the patient has isolated angioedema then C4 levels & a C1 inhibitor antigenic level should be obtained tx Immediate: immediate assessment & ongoing airway protection; epi if severe Mast-cell mediated: epi (if severe), steroids, antihistamines Bradykinin-mediated: C1 inhibitor concentrate, ecallantide, icatibant

Answer 3

Edema of the superficial layers of the skin due histamine-related increased vascular permeability Type I (IgE) immediate hypersensitivity reaction sx Triggers: foods, meds, heat or cold, stress, insect bites, environmental, & infection - chronic (>6wks) Sudden onset of circumscribed hives or wheals (blanchable, raised, erythematous areas on the skin or mucous membranes) that may coalesce *intense pruritis *usually transient (often disappearing within 24hrs) dx: clinical tx Antihistamines (H1 blockers) initial - second gen: cetirizine, loratadine, fexofenadine - first gen: diphenhydramine, hydroxyzine, chlorpheniramine H2 blockers (ranitidine) may be added if no response to H1 blockers Severe, recurrent, persistent: steroids

Answer 4

Definition: distinct & potentially life-threatening severe ADR characterized by a morbilliform cutaneous eruption w/ fever, LAD, hematologic abnormalities, & multiorgan manifestations sx Prodrome: fever, pharyngitis, malaise 2-3d before rash onset Skin: morbilliform exanthem w/ accentuation on face, upper trunk, proximal extremities; may progress to erythroderma; pruritis common *desquamation develops days-weeks after initial eruption; can last several weeks Other manifestations: facial edema (esp. periorbital), LAD, mucosal involvement (cheilitis, pharyngeal erythema) Organ system involvement: hepatitis, tubulointerstitial nephritis, pulmonary sxs (SOB, tachypnea, cough) *rash/other abnormalities resolve 1-2mo after med DC Autoimmune complications: Graves, DM1, AIHA DX Criteria: acute onset exanthema w/ fever, suspicion of drug reaction, hospitalization, LAD, involvement of ≥1 internal organ, & hematologic abnormalities (lymphopenia, lymphocytosis, atypical lymphocytosis, eosinophilia >10%, thrombocytopenia) CBC: can show lymphocytosis, atypical lymphocytosis, eosinophilia, thrombocytopenia LFTs: ↑ ALT, alk phos; CMP: ↑ creatinine; ↑ LDH UA: proteinuria, eosinophilic sediment Blood PCR: HHV-6, HHV-7, EBV, CMV Hepatitis panel: HAV IgM Ab, HBsAg, HBcAb (IgM), HCV viral RNA TFTs: @baseline, again @6wks tx DERM CONSULT! *identify & DC causative medication *fluid replacement, electrolyte correction Mild, predominantly cutaneous: topical corticosteroids; antihistamines for pruritis Significant systemic involvement: *systemic steroids; prednisone, methylprednisolone *IVIG for no response to steroids; plasmapheresis, immunosuppressive drugs are other options

Answer 5

sx Prodrome: high fever + 3Cs (cough, coryza, conjunctivitis); usually lasts 3d Koplik spots: small red spots w/ white centers on oral mucosa *rash follows by 1-2d Rash: maculopapular rash; cephalocaudal progression (head downwards) *spares palms/soles; fades ~4d; left w/ persistent cough for 10-14d dx Clinical Measle-specific IgM antibodies, PCR Vaccine: MMR @12-15mo, 2nd dose @4-6y tx Supportive: acetaminophen, ibuprofen, oral hydration *vitamin A for young/severely malnourished children; boosts immune response; ↓ risk of complications & death

Answer 6

Etiology: group A strep sx Prodrome: fever, chills, pharyngitis Rash: diffuse erythema that blanches w/ pressure + multiple small papular elevations w/ sandpaper texture *axillae/groin 🡪 trunk/extremities (spares palms/soles) Flushed face w/ circumoral pallor & strawberry tongue Pastia’s Lines: linear petechial lesions seen at pressure points, axillary, antecubital, abdominal, or inguinal areas dx: clincial tx Penicillin G or VK first line - amoxicillin - macrolides if PCN allergy - clindamycin, cephalosporins

Answer 7

sx Prodrome: flu-like sxs (mild fever), arthralgias, postauricular LAD Rash: erythematous, maculopapular rash; cephalocaudal spread (face downwards) *spares palms/soles; disappears within 3d aka “3d measles” *spreads much more rapidly than measles, does not darken/coalesce Forchheimer spots: pinpoint red macules & petechiae on soft palate & uvula dx: Clinical Rubella-specific IgM Ab via EIA tx Supportive: acetaminophen, ibuprofen, oral hydration *immunoglobulin in exposed individuals Vaccine: MMR @12-15mo, 2nd dose @4-6y Complications: teratogenic in 1st TM *deafness, cataracts, congenital heart defects (PDA)

Answer 8

Etiology: parvovirus B19 – infects & destroys reticulocytes, leading to a ↓ or transient halt in erythropoiesis sx Prodrome: flu-like sxs (mild fever, HA, malaise); *rash follows by a few days Rash: “slapped cheek” rash; lacy reticular rash on extremities; spares palms/soles; resolves in 2-3wks *arthritis or arthralgias in older children/adults dx: Clinical Serologies: parvovirus B19-specific IgM antibodies tx Supportive: acetaminophen, NSAIDs Complications: hydrops fetalis in pregnancy, aplastic crisis in pts w/ sickle cell

Answer 9

Etiology: MC caused by HHV-6; less commonly HHV-7 sx Prodrome: 3d of high fever – child appears well during febrile phase; can reach >104F Rash: pink maculopapular blanchable rash *starts on trunk 🡪 face (only viral exanthem that starts on the trunk) dx: Clinical Viral culture/PCR for confirmation IgG antibodies against HHV-6/7 tx Supportive: rest, fluids, antipyretics (acetaminophen) Immunocompromised: antivirals (ganciclovir) Complications: febrile seizures

Answer 10

Etiology: coxsackie virus A Transmission: person-person, respiratory droplets, feces, direct contact w/ contaminated surface MC in children <5yrs; MC in summer/early fall sx Prodrome: flu-like sxs, oral pain *rash follows within few days Rash: painful vesicles & ulcers in mouth 🡪 vesicles on palms/soles *usually clears within 10d dx Clinical – viral culture/PCR of throat swab or stool sample Coxsackie-specific immunoglobulin A tx Supportive: acetaminophen, ibuprofen, hydration, topical lidocaine; usually resolves in 1wk Complications: aseptic meningitis, Guillain-Barre syndrome

Answer 11

Etiology: coxsackie virus (esp. type A) MC in children 3-10yrs; MC in summer/early fall sx Sudden onset high fever Stomatitis: small yellow white papulovesicular lesions on posterior pharynx (soft palate, uvula, tonsils) that ulcerate before healing *anorexia due to pain common *pharyngitis, odynophagia *NO SORES ON HANDS/FEET In older children: +/- malaise, HA, N/V, neck stiffness, back stiffness dx: Clinical Coxsackie-specific immunoglobulin A; viral culture tx Supportive: acetaminophen, ibuprofen, hydration

Answer 12

Etiology: paramyxovirus sx Prodrome: low-grade fever, fatigue, myalgia, malaise, HA, earache Parotitis: parotid gland pain & swelling; usually bilateral PE: parotid gland swelling & tenderness dx Clinical, serologies ↑ amylase, leukopenia w/ a relative lymphocytosis tx upportive: acetaminophen, ibuprofen, analgesics Complications: epididymo-orchitis MC

Answer 13

VZV causes 2 clinically distinct diseases: *Primary: varicella (chickenpox) *Reactivation: herpes zoster (shingles) Transmission: aerosolized droplets, direct contact w/ vesicular fluid Incubation: 14-21d; asymptomatic Travels retrograde to trigeminal ganglion & dorsal root ganglia where it can remain dormant in a latent state for many years; later, if immune system weakens (aging, stress, immunosuppressive therapy), virus can be reactivated & travel anterograde through sensory nerve to skin (herpes zoster/shingles)

Answer 14

Varicella (chickenpox): “dew drops on a rose petal” Prodrome: fever, malaise, anorexia, pharyngitis; rash appears 24h later Rash: *appears in successive crops over several days *starts as macules, rapidly become papules, then vesicles; can develop pustular component followed by formation of crusted papules; crusts fall off within 1-2wks; leave temporary area of hypopigmentation *lesions in different stages of development, PRURITIC!!! Herpes zoster (shingles): Prodrome: pain, itching, or tingling in area where rash will develop Rash: single stripe of vesicles (single dermatome); don’t cross midline *usually resolves within 1mo, but pain can last >90d 🡪 postherpetic neuralgia Zoster Ophthalmicus: involves ophthalmic division of trigeminal nerve; 5 *eye pain, redness, swelling + fever + painful vesicular rash Zoster Oticus (Ramsay-Hunt Syndrome): involves facial nerve (8) *otalgia; lesions on ear, auditory canal, & TM; facial palsy, hearing loss

Answer 15

Clinical PCR: viral DNA; confirmatory Blood tests: IgM antibodies Tzanck smear: *multinucleated giant cells Zoster Ophthalmicus: *dendritic lesions on slit lamp if keratoconjunctivitis is present

Answer 16

Varicella (chickenpox): resolves in 1wk; develop immunity *healthy children <12yo: supportive (ASPIRIN 🡪 REYE) *≥13y & unvaccinated, immunocompromised: antivirals PO acyclovir, valacyclovir, famciclovir *varicella-zoster immune globulin (VZIG) Herpes zoster (shingles): rash usually resolves in 1mo *acyclovir, valacyclovir, famciclovir within 72h to prevent postherpetic neuralgia Zoster Ophthalmicus: PO antivirals, can add acyclovir ophthalmic Ramsay-Hunt: PO acyclovir, corticosteroids Postherpetic Neuralgia: gabapentin, TCAs, topical lidocaine gel, capsaicin Vaccines: varicella @12-15mo, second dose 4-6y; recombinant zoster vaccine (RZV) in pts >50y, 2 doses 2-6mo apart

Answer 17

HSV 1 – cold sores Transmission: direct contact w/ contaminated saliva or other infected bodily secretions HSV 2 – genital herpes Transmission: sexually transmitted

Answer 18

HSV 1: Primary lesions: *most are asxs but may cause tonsillopharyngitis in adults & gingivostomatitis in children *Herpetic Whitlow: herpes of the finger Secondary lesions: *Herpes Labialis (cold sore): prodromal sxs (pruritis, burning, tingling, pain) followed by grouped vesicles on an erythematous base; crust over before healing HSV 2 (genital herpes): Prodrome: burning, paresthesias, numbness; dysuria, fever Rash: multiple, shallow, tender ulcers; grouped vesicles on an erythematous base; inguinal LAD

Answer 19

dx PCR Tzanck smear: multinucleated giant cells tx HSV 1: Orolabial: PO valacyclovir (2g BID x1d) HSV 2: Acyclovir, valacyclovir, famciclovir

Answer 20

MC in southwestern/midwestern US Spider: violin pattern sx Local effects: local burning/erythema for 3-4hrs 🡪 blanching of affected area (due to vasoconstriction) 🡪 erythematous margin around the ischemic center “red halo” for 24-72hrs 🡪 hemorrhagic bulla that undergoes eschar formation 10% may develop skin necrosis Systemic effects: fever, chills, N/V, morbilliform rash tx Local wound care + pain control - local wound care: clean w/ soap & water, cold packs, elevation (most heal spontaneously within days to weeks) - pain control: NSAIDs (opioids if severe); tetanus prophylaxis if needed

Answer 21

Spider: red hourglass shape PATHO: produces a neurotoxin sx Local sxs: pain at bite site Systemic & neurologic sxs: onset within 30min-2hrs – muscle pain (most prominent feature), spasms, rigidity Usually self-limited w/ resolution within 1-3d PE: blanched circular patch w/ a surrounding red perimeter & central punctum (target lesion) tx Mild: wound care + pain control – soap/water, NSAIDs, opioids Moderate to severe: muscle relaxants (BDZs, methocarbamol) Antivenom reserved for pts not responsive to above

Answer 22

Results from an abscess, or sinus tract, in the upper part of the natal (gluteal) cleft Pilonidal means “nest of hair” – a hair in the natal cleft allows hair to be drawn into the deeper tissues via negative pressure caused by movement of the buttocks, follicular occlusion from stretching, & blocking of pores w/ debris MC seen in pts in late teens/early 20s; male predominance Less frequently seen in children & >45yrs sx 3 distinct clinical presentations: *Asymptomatic: painless cyst or sinus at the top of the gluteal cleft *Acute Abscess: severe pain, swelling, discharge from the top of the gluteal cleft that may or may not have drained spontaneously *Chronic Abscess: persistent drainage from a sinus tract at the top of the gluteal cleft dx: clinical tx Acute: prompt I&D *abx only needed if cellulitis suspected (cefazolin + metronidazole or Augmentin) Chronic: surgical excision