Dermatology Flashcards
1
Q
atopic dermatitis (eczema)
A
- more . susceptible to skin infxns, S. aurus (most common), associated allergic triad: asthma, allergic rhinitis, atopic derm
- onset before age 2, 10% diagnosed after age 5
- acute phase: vesicular, weeping, crusting eruption
- subacute: dry, scaly, red papules and plaques
- chronic: excoriations and lichenifiecation of skin, xerosis, hyperpigmentation, flexural lichenification in adults: anterior and lateral neck, eyelids, forehead, face, wrists, dorsa of feet, hands, facial and extensor involvement in children and infants
- dx: complications: secondary bacterial infxns - pustules and crusts
- tx: moisturizers or emollients: cetaphil or eucerin (ointments = aquaphor, patroleum jelly)
- bathing removes scale, crust irritants, allergens, limit use of nonsoap cleansers
- topical steroids = first line for flareups
- topical calcineurin for mod-severe (pimecrolimus/elidel or tacrolimus)
- abx to reduce flare ups
- UV phototx for severe or refractory
2
Q
nummular eczema
A
- one or several . coin-shaped plaques on extreities, typically on backs of hands
3
Q
erythema multiforme
A
- delayed-type hypersensitivity rxn to infxn or drugs, adults 20-40, infectious causes = HSV 1 or 2, M pneumo, fungal
- meds: barbiturates, hydantoins, NSAIDs, PCN, phenothiazines, sulfonamides
- sxs: acute, polymorphous eruption of macules, papules, and “target or iris lesions” without scaele = round shape, 3 concentric zones, itching or burning at site
- signs: sharply demarcated red or pink macules → papular → plaques , central portion becomes darker red, brown, dusky, or purpuric, crusting or blistering of center, symmetrically distrib, spreads distal to prox, minimal mucous memb involvement
- dx: <10% of body surface area
- tx: tx existing infxn or dc drug (mild = no tx; recurrent = acyclovir continuously)
- prognosis: resolves spontaneously in 3-5wks without sequelae, may recur
4
Q
Stevens-Johnson syndrome
A
- most often caused by meds, MC = sulfonamides (TMP-SMX), allopurinol, antipsychotics, antisiezure meds
- sxs: no typical target lesions, flat atypical targets, confluent purpuric macules on face and trunk, severe mucosal erosions at one or more sites
- dx: <10% of body surface area
- tx: stop meds immediately and transfer pt to burn center
5
Q
toxic epidermal necrolysis
A
- fever, mucocutaneous lesions, necrosis . and sloughing of epidermis (diffuse, macular rash with indistinct margins and central purpuric region followed by eventual formation of vesicles and bullae as epidermal necrosis develops over days; start on face . and spread inf to trunk and lower extrems), no typical target lesions, flat atypical target lesions, begins with severe mucosal erosions and progresses to diffuse, generalized detachement of epidermis
- dx: >30% of body surface area, nikolsky sign + (sloughing of superficial skin layers with gentle pressure), must have erythema and sloughing of mucosal surfaces including conjunctiva, oral, and vagina (2 or more)
- bx: full-thickness involvement of dermis
- tx: prednisolone
6
Q
bullous pemphigoid
A
- IgG Ab complexes deposit between the epidermis and dermis causing formation of fluid-filled bullae
-
autoimmune skin disorder with subepidermal blistering, mostly elderly onset 60-80, M=W, S. aureus
- Scenario: elderly who takes multiple meds
- sxs: large, tense bullae, but may begin as an urticarial eruption, fluid with clear fluid or hemorrhagic, discrete lesions arise on axilla, medial thigh, groin, abdomen, flexor arms, and lower legs, itchy, NOT PAINFUL, tense, not easy to rupture, lesions start as urticarial eruption, developing into bullae over wks to mos, no scar formation after but milia appear at sites of perv involved skin
- dx: nikolsky sign -: no sloughing of skin w/ light pressure
- skin bx: REQUIRED FOR DX - subep separation and intact ep
- tx: oral prednisone, alone or in combo with steroid-sparing Asathioprine, mycophenolate mofetil or tetracycline
7
Q
urticaria
A
- vascular rxn of skin marked by transient appearance of smooth, slightly elevated papules or plaques (wheals) that are erythematous and often itchy, IgE triggers release of histamine from mast cells
- etiology: drugs (NSAID, ASA, opiates, succinylcholine, abx), radiocontrast media\
- sxs: rapid onset pruritic erythematous wheals (lack of ep change, intense itching, presence of advancing edge and receding edge), life-threatening angioedema, features of anaphylaxis (HoTN, resp distress, stridor, GI distress, swallowing difficulty, jnt swelling, pain)
- dx: RAST
- tx: 2nd gen H1 antag: cetirizine, loratadine, fexofenadine (1st line), H2 antag (in combo with 2nd gen H1s - famotidine, ranitidine), 1st gen H1 antac (diphenhydramine, hydroxyzine, chlorpheniramine), epi for laryngeal angioedema
8
Q
Lice
A
- Head: pediculus humanis capitis or pediculus capitis
- Genital: phthirus pubis
- Transmission: sexual contact, clothing, towels
- sxs: severe itching of scalp, body, groin
- signs: live lice and nits attached to hair on exam
- dx: requires observation of live lice, most commonly found behind ears and on back of neck
- tx: permethrin cream shampoo (elimite)
9
Q
scabies
A
- mites tunnel into skin, lay eggs, depositing feces (scybala), causing delayed type IV hypersens. rxn
- highly contagious via skin-skin contact, towels, bed linens, or clothes, caused by skin mite Sarcoptes scabiei var hominis
- sxs: burrows and typical distrib on . hands, feet, waist, axilla, or groin - linear marks, severe itching, especially at night
- signs: erythematous papules on wrists, between fingers, and in genital area, excoriation, characteristic burrows on hands, wrists, and ankles and in genital region
- dx: hx of itching, rash in typical distrib, hx of itching in close contacts, definitive dx = mites, eggs, fecal pellets, skin scraping from nonexcoriated burrows, papules, or vesicles
- tx: overnight tx with permethrin (no longer contagious after one tx although itching may continue), topical steroids and oral antihist for itching
10
Q
Spider bites
A
- Black widow: presynaptic release of most neurotrans (AcH, NE, Dop, glutamate)
- sxs: mod to severely painful bite, no surrounding inflamma, muscle spasms and rigidity starting at bite site w/in 30min-2h, spreads proximally to abd and face, rebound tenderness mimicking acute appy
- tx: resolves over 2-3d, death rarely occurs
- brown recluse: local cytotoxicity w/ subsequent ulcerating dermonecrosis, occurs early in morning, painless - delayed reaction (3-7d), arthralgias, fever, chills, maculopap rash, N/V, progress to ulcerating dermonecrosis at bite site, most ulcers heal over 1-8wk
- Tarantula: urticating hairs on dorsal abdomen, penetrate skin causing foreign body keratoconjuctivitis or ophthalmia nodosa, refer opthalmo if suspected eye injury (slit lamp exam)
11
Q
First disease: measles
A
- AKA rubeola
- incubation: 2wk
- sxs: prodromal (malaise and anorexia), then high fever and lethargy (4-7d), 3 Cs Triad (cough, coryza (runny nose, congestion), conjunctivitis), rash on day 3
- signs: Koplik spots (blue/gray spots on buccal mucosa), blanching erythematous macules and papules on face at hairline, sides of neck, and behind ears (coalesce into patches and plaques on trunk and extrems (palms/soles) lasts 5-7d
- dx: clinical, IgM titer, IgG, viral cx from throat and nasal swab, RT-PCR
- tx: ibuprofen, fluids, vitA
- complications: PNA, OM, endcephalitis
12
Q
second dz: scarletina
A
- S. pyogenes, group A strep
- transmission: resp droplets, common in overcrowded places
- sxs: fever, abd pain, HA, pharyngitis, rhinorrhea, rash 12-48h after onset of fever (erythem patches below ears, on neck chest and axilla, dry ROUGH TEXTURE OF FINE SANDPAPER, blanchable, disseminates to flexural areas (axillae, pop fossa, inguinal folds), pastia lines: confluent petechiae in skin creases, neck, antecubital, axilla, groin
- signs: enlarged ant cerv lymph nodes, red scattered petechiae on soft palate, STRAWBERRY TONGUE (heavily coated with white membrane with edematous red papillae)
- dx: clinical, CBC, leukocytosis with left shift, cx or rapid strep test, antistreptolysin titer
- tx: calamine, tylenol, amox, macrolide
- prognosis: desquamation begins 7-10d after resolution of rash
- complications: rheumatic fever, septicemia, vasculitis, hepatitis, OM, PNA, osteomyelitis, glomerulonephritis
13
Q
third disease: Rubella
A
- blueberry muffin baby, german measles
- Rubella virus (RNA virus rubivirus), 2-3wk incubation, prodromal phase absent in children
- transmission: droplet
- incubation period: 14-19d
- sxs: mild URI, low grade fever, macular rash day 1, face → trunk → limbs, arthralgia
- signs: postauricular, postcervical, and occipital nodes (tender, generalized)
- clinical dx
- tx: ibuprofen, fluids, contageious for 7d after rash onset
- complications: PDA, pulm art stenosis, aortic sten, ventricular defects, thrombocytopenic purpura w/ purple macular lesions, cataracts, retinopathy, sensorineural deafness
14
Q
Fifth disease: erythema infectiosum
A
- slapped cheek syndrome
- parvovirus B19, 4-14d incubation
- transmission: aerosolized resp droplets, mother to fetus
- sxs: mild URI, HA, pharyngitis, itching, coryza, abd pain, arthralgias, low fever, 1wk later slapped cheek (nasal perioral, and periorbital sparing), lacy reticular rash on prox extrems and trunk, palms and soles spared
- complications: arthritis, anemia, fetal hydrops
- clinical dx
- tx: ibuprofen, fluids
- NOT INFECTIOUS when rash occurs, may attend school or childcare (only infxous in mild URI phase (2-3d))
15
Q
sixth disease: Roseola
A
- HHV 6B or 7, 5-15d, MC in 9-12mo olds
- sxs: high fever x3-4d +/- febrile seizure, after 3d fever dissapates and rash occurs (small pink blanchable rash - morbilliform, nagayama spots (red papules on soft palate and base of uvula))
- dx: CBC, UA, blood cx, CSF exam, roseola IgM
- tx: ibuprofen, fluids
- complications: febril seizures
