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; occurs more frequently in urban areas and higher SES
- 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 refrac
2
Q
lichen planus
A
- chronic, inflammatory autoimmune dz, MC in perimen women 30-60yo, commonly associated with hep C
- sxs: acute onset, affects flexor surfaces of . wrists, forearms, legs
- 6 Ps: planar (flat topped), purple, polygonal, pruritic, papules, plaques, pruritis
- signs: Koebner phenomenon - follow lines of trauma, covered by lacy, reticular, white lines (wickham striae), postinflammatory hyperpigmentation as skin lesions clear, especially with darker skin
- dx: 4mm punch bx helpful and required for atypical dz
- tx: high potency topical steroids (first line) for all forms: clobetasol
- oral antihist, for itching, intralesional triamcinolone (kenalog) for hypertrophic lesions, topical calcineurin inhib (tacrolimus or pimecrolimus) for vulvovaginal lichen planus, 3-6wk oral prednisone for severe widespread cases
- prognosis: most self-limites: resolves spontaneously within 1-2y although recurrence is common
- screen for hep C
3
Q
pityriasis rosea
A
- children and young adults, related to herpes type 7, not contagious, common on trunk, upper arms, and thighs
- sxs: begins w/ herald patch (usually found on trunk or proximal thigh), pruritis, progress to generalized rash in 1-3wks, multiple salmon-pink oval papules scattered symmetrically, christmas-tree like distribution over neck, trunk, and proximal extremities, annular plaques with collarette scale
- tx: self-limiting (reassurance) in 6-8 wk without tx, antihistamines for itching
4
Q
erythema multiforme
A
- delayed-type hypersensitivity rxn to infxn or drugs
- includes SJS and TEN
- meds: barbiturates, hydantoins, NSAIDs, PCN, phenothiazines, sulfonamides
- MCC = herpes simplex; cutaneous lesions are true three ring targets, presents on extensor surfaces, palms, soles, itching or burning at site, disease stays localized (unlike SJS/TEN)
- 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)
- oral antihist help suppress prutitis
- prognosis: resolves spontaneously in 3-5wks without sequelae, may recur
5
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, skin bx is dxic
- tx: stop meds immediately and transfer pt to burn center
6
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
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 - in children are a signs of child abuse bc only transmitted via sexual contact
- Body: firm sign of poor hygiene; can be a potentially serious vector for infxns such as epidemic typhus, louse-borne relapsing fever, and trench fever
- 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; face and scalp usually spared in older children and adults
- 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), treat once more 1wk later, topical steroids and oral antihist for itching
10
Q
acne vulgaris
A
- four factors responsible: increased sebum production, hyperkeratinization of follicle, colinization by P. acnes, inflammatory rxn
- occurs on face, neck, chest, back, adding benzoyl peroxide to abx tx prevents risk of bact resistance
- after tx goals reached, oral abx should be replaced by topical retinoids for maintenance tx
- MC skin disorder in US, MCC = P. acnes, more prevalent in adolescents and more severe in males
- pathology: plugged follicles, retained sebum, bacterial overgrowth, release of fatty acids
- sxs: noninflamm → open comedones = blackheads, closed comedones = whiteheads
- inflammatory: erythematous papules, pustules, nodules or cysts
- dx: testosterone, FSH, LH, DHE-5 levels (not necessary for dx)
11
Q
acne tx: mild, moderate, severe
A
- mild: noninflamm → topical retinoids, benxoyl peroxide, salicylic acid or azelaic acid; inflamm → topical tretinoin, topical benzoyl peroxide, topical abx (erythro or clinda)
- moderate: oral abx (tetracyclines, erythromycin, doxycycline, minocycline, bactrim, clindamycin) effective of monotx but better when combined w/ retinoids (topical benzoyl peroxide)
- severe: oral isotritinoin, must be member of iPLEDGE, premature closure of long bones, visual changes, elevated LFTs, laeukopenia, triglyceridemia, teratogenicity, oral abx topical retinoid benzoyl peroxide
12
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
13
Q
second disease: 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
14
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
15
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))
