Dermatology Flashcards
Treatment for non-purulent cellulitis
PO:
dicloxacillin
cephalexin
clindamycin
IV:
cefazolin
naficillin
Clindamycin
Treatment of purulent cellulitis
PO: Clindamycin TMP-SMX Doxy Linezolid
IV:
Vancomycin
Treatment of skin abscess
I&D
Risk of endocarditis - IV vancomycin 1 g prior to I&D
PO: clindamycin TMP-SMX Doxycycline Linezolid
IV: vancomycin
Hidrandenitis suppurativa
chronic occlusion of apocrine glands - axila, groin, perineum
Tx:
avoid skin trauma, gentle cleansing, smoking cessation, wt loss
Mild: topical clindamycin, punch debridement
Severe - oral doxycycline or minocycline, more invasive surgical debridement
Alt: intralesional steroids, anti-adrenegic drugs, TNF-a inhibitors, oral retinoids
Necrotizing fasciitis
Unexplained, excruciating pain in the absence of or beyond areas of cellulitis
Erythema with blister and bullae formation and possible crepitus
Perineal cellulitis with abrupt onset in rapid spread - Fournier gangrene
Most common underlying conditions: DM Alcoholism Immunosuppression Malignancy
Dx: surgical exploration
Rapidly worsening cellulitis with severe pain
crepitus - air on XR
Tx:
Immediate aggressive surgical debridement
Antibiotics:
Carbapenem (imipenem or meropenem) or beta-lactam plus beta-lactamase inhibitor (pip-tazo)
PLUS clindamycin
PLUS vancomycin
Impetigo
MC: MSSA
MRSA
S. pyogenes
Papules -> vesicles with redness -> pustules -> yellow crust
MC on face
Tx:
mild - mupirocin
Mod-severe - dicloxacillin, cephalexin
MRSA:
Clindamycin
TMPSMX
doxy
Acne medications known for causing photosensitivity
Tetracycline
Doxycycline
Tretinoin - topical
Acne contributing factors and treatment approaches
- hyperkeratosis
Retinoic acid
- Tretinoin - topical
- Isotretinoin - PO: risk hepatotoxicity, teratogenic, drying/cracking skin and lips; depression, SI; elevated TGs - Sebum overproduction
- Isotretinoin
- Tretinoin
- Spironolactone
- OCPs - Propionibacterium acnes proliferation
-Erythromycin
-tetracycline
-doxycycline
-minocycline
Topical - clindamycin, benzoyl peroxide - Inflammation
- steroids sparingly, injected into lesion
- can induce acne
Rosacea
Middle aged patient
Facial erythema with telangectasias starting at the nose and cheeks
Recurrent facial flushing - hot/spicy foods, alcohol, temperature extremes, emotional reactions
Inflammatory papules, pustules, cysts, and/or nodules - similar to acne without comedones
Ocular blepharitis, conjunctivitis, and/or keratitis
Rhinophyma - sebaceous gland hyperplasia of the nose
Tx:
Topical:
Metronidazole
Azelaic acid
Systemic: - severe or unresponsive
Tetracycline, doxycycline or minocycline
Isotretinoin for refractory
Laser therapy for rhinophyma
Herpes simplex virus
Latent in sensory ganglia
Primary infection - flu like illness
Eyes -> vision impairment
Esophagus -> odynophagia, dysphasia
Whitlow - fingers, cuticle area
Dx:
Tzanck smear - rules in
Viral cx
Serology - Ab
Disseminate with vertical transmission - severe neurological involvement - temporal lobe encephalitis
Tx:
Acyclovir
famciclovir
valacyclovir
Varicella
Prodrome: malaise, fever, pharyngitis, headache, and myalgia for 24 hours prior to rash
Pruritic, evolving rash: red macules -> tear drop vesicles -> rupture and cresting over
- vesicular rash starts on face and trunk then spreads to extremities
- rash appears in successive crops of vesicles over 2-4 days
- most lesions fully crusted by 6 days
Risk: skin bacterial superinfections - S. pyogenes
-adults made about pneumonia and/or encephalitis
Tx:
Antihistamines for pruritis
Cut fingernails- avoid excoriations
Acetaminophen for fever
Acyclovir: over 12 yo, hx of chronic cutaneous or CV disorders, on intermittent oral/inhales steroids, or taking chronic salicylates
Ppx: varicella vaccine at 1 yr, 4 yr
Shingles
Reactivation of herpes zoster virus
Painful, group vesicles any dermatomal distribution
postherpetic neuralgia possible
Transmission through direct contact with active lesion
Vaccine ppx - not in pregnant or immunocompromised
Tx: Uncomplicated, within 72 hrs of start of sxs: -Valacyclovir -Vamciclovir -Acyclovir
Analgesia with opioids
+/- prednisone if severe sxs and no contraindications
Treatment of postherpetic neuralgia
gabapentin pregabalin TCAs lidocaine patches capsacin cream
Treatment options for cutaneous warts
2/3 resolve spontaneously within two years
Salicylic acid - first line
Liquid nitrogen
5FU and imiquimod
curettage, trichloroacetic acid, cantharidin, surgical excision
Molluscum contagiosum
mostly in children and patients with HIV
Pox Virus
Flesh colored lesions with central umbilication, shiny
Self-limited
Tx: curettage imiquimod cryotherapy laser therapy
Tinea vesicolor
Malassezia furfur
Hyperpigmented or light brown/ pink macules often found on back and shoulders
Hyphae and spores - spaghetti and meatballs
Tx: Ketoconazole 2% shampoo Topical antifungal - terbinafine Selenium sulfide Oral antifungal for extensive disease - ketoconazole, fluconazole, itraconazole
Tinea
Differentiated by location - capitis (scalp), corporis (body), cruris (groin), pedis (foot), unguium (nails)
Microsporum, Trichophyton, Epidermophyton
pruritic, erythematous, blisters, scaly plaques, Central clearing
Tx:
Skin:
topical - clotrimazole, terbinafine, nystatin
oral - terbinafine, itraconazole, fluconazole
Scalp: oral - griseofulvin (first line), terbinafine, itraconazole, fluconazole
nails:
Oral - terbinafine, itraconazole, fluconazole - 6 weeks for finger, 12 weeks for toe - check LFTs before starting
Topical - ciclopirox, efinaconazole
Intertrigo
candida albicans
Skin creases - satellite lesions
KOH - pseudohyphae
Tx: topical clotrimazole or terbinafine
(contact derm - no folds, no satellites)
Scabies
severe pruritis with burrows and papules located on extremities in and between fingers and toes - worse after hot bath
Skin scrapings will show mites, eggs
Tx: permethrin cream
Oral - ivermectin
Pediculosis capitis
pruritus
Tx: permethrin cream or shampoo - rinse out after 10 min, then comb out lice and nits
Alt: topical malathion or ivermectin
Pediculosis corporis
pruritis
Tx: permetherine cream and leave on for 8-10 hrs
Pediculosis pubis
tx with permetherine or pyrethrin cream - rinse out after 10 min then comb
alt: topical malathion and ivermectin
Erythema multiforme
IgM immune complex deposition
Features:
Skin lesion with target appearance - dull red center, pale zone, and darker outer ring
-can involve palms and soles
many different shapes
Develop over 10+ days: macule -> papule -> vesicles/bullae in the center of the papule
Common sites: hands/forearms, soles/feet, face, elbows and knees, penis and vulva
Severe form invovles mucous membranes -> SJS/TEN
Tx: stop inciting medication Symptomatic treatment with antipuritics If severe -> systemic glucocorticoids HSV hx - acyclovir or valacyclovir
Drugs/other causing erythema multiforme
PCN sulfonamides NSAIDs OCPs Anticonvulsant meds HSV Mycoplasma pneumoniae
Stevens Johnson sn vs Toxic epidermal necrolysis
SJS - less severe
-skin sloughing - epidermal detachment limited to less than 10% of body surface area
TEN - at least 30% skin detaching
Always involves mucous membranes
labs:
low H&H
elevated AST, ALT
Tx: Stop offending agent Corticosteroids Analgesia IVF Burn unit Admit Acyclovir if HSV hx
Seborrheic dermatitis
Chronic relapsing dermatitis associated with sebaceous glands
-can be caused by Malassezia furfur
Erythematous plants with greasy looking yellowish scales
Tx:
Scalp: medicated shampoo - ketoconazole, selenium sulfide, ciclopirox
Alt - tar containing shampoo
Skin: low potency topical steroids or topical antifungal Cream - ketoconazole
Seborrheic keratosis
Noncancerous skin growth that originates in keratinocytes
Various presentations: flat, raised, tan colored, warty, “pasted on” appearance
No treatment needed
Atopic dermatitis (eczema) treatment
Skin hydration: emollients - petroleum jelly or other low water content creams
Topical steroids
Calcineurin inhibitiors - tacrolimus or pimecrolimus
Severe or resistant cases - UV light therapy, systemic steroids, immunosuppresants - methotrexate, cyclosporine, azathioprine
Abx for open lesions - cover S. aureus and Strep spp.
Psoriasis
Extensor surfaces
Bleed when scale removed - Auspitz sign
Bx: thickened epidermis, absent granular layer, nucleated cells in stratum corneum
20% with arthritis
Tx:
Mild to mod:
Topical steroids and emollients
Alts: tar based products, topical retinoids (tazarotene), topical vitamin D (calcipotriene), anthralin, calcineurin inhibitors - tacrolimus, pimecrolimus
Severe: Photo therapy Oral retinoids Immunosuppressants - methotrexate, cyclosporine Adalimumab, etanercept, infliximab
Pityriasis rosea
Papular lesions on trunk and extremities in Christmas tree pattern
Herald patch 2-5 cm
Tx:
Self-limited 4-6 weeks
Mod - potency topical steroids for pruritis
Severe - UV therapy, acyclovir, erythromycin
Erythema nodosum
Inflammation of the subcutaneous fat septa
Painful erythematous nodules - anterior tibia, trunk
Delayed immuno rxn to infection, vascular dz, drugs
Accompanied with malaise, arthralgias, fever
Labs: + ASO, elevated ESR
Bx - fatty inflammation
Tx: self limited NSAIDs Potassium iodine Corticosteroids
Causes: SPUDBITS Strep Pregnancy Unknown Drugs Behcet dz IBD TB Sarcoidosis
Lichen planus
Young - assoc HIV; older - Hep C
Skin: pruritic, purple, polygonal papules and plaques - shiny and flat, common on flexor surface of extremities (wrist)
Wickham’s striae - white, lace-like pattern on surface of papules/plaques
Mucous membrane: Wickham’s striae in lateral buccal mucosa and possible erosive lesions may be come infected with Candida
Genital involvement - limited to violaceous papules on glans penis and vulva
Tx:
corticosteroids - medium to high potency - topical, interlesional, oral if topical unsuccessful
Acitretin - oral retinoid
Stages of decubitus ulcers
Stage 1: pressure related alteration in intact skin - change in color, consistency, sensation or temperature
Stage 2: superficial ulcer, abrasion, or shallow crater
Stage 3: Full thickness skin loss with damage to the subcutaneous tissues - deep crater
Stage 4: extensive destruction or necrosis; damage to muscle, bone or supporting structures
Stasis dermatitis
eczematous dermatitis with inflammatory papules, scaly and crusted erosions, increased pigmentation, stippling with recent and old hemorrhages, possible ulceration
Dx: duplex U/S - venous reflex
Tx: wt loss compressive dressings or stockings leg elevation topical steroids vein ablation
Pemphigus vulgaris
Flaccid bullae - easy to rupture (+ Nikolsky)
Oral lesions
Anti-desmosome Ab - epidermis
Tx:
High-dose systemic steroids
Azathioprine or mycophenolate mofetil (steroid-reducing adjuvant)
Abx for secondary infections
Prognosis: fatal if untreated, mortality of 5% with treatment
Bullous pemphigoid
Tense bullae
Rare oral lesions
Anti-hemidesmosome Ab - dermal-epidermal junction (BM)
Tx: Topical - clobetasol Oral prednisone if topicals not possible Chronic management: mycophenolate mofetil, azothioprine or methotrexate Prognosis better than pemphigus
Porphyria cutanea tarda
Deficiency in hepatic uroporphyrinogen decarboxylase
Risk: Hep C, alcohol abuse, excess iron
Chronic blistering of sun exposed skin - facial hypertrichosis, hyperpigmentation, pseudoscleroderma
Dx: elevated plasma porphyrins
Tx:
phlebotomy
Hydroxychloroquine
Avoid sun, alcohol, estrogens, iron supplements
Acute porphyria presentation
Systemic symptoms
Abdominal pain, vomiting
Neuropathy
Mental disturbances
elevated urinary porphyrobiligen
Actinic keratosis
Precancerous skin lesion
Risk: sun exposure
Erythematous papules with rough,, yellow brown scales
Bx: dysplasia of epithelium
Tx: topical 5FU, imiquimod and cryotherapy
-> squamous cell carcinoma
Squamous cell carcinoma of skin
Skin cancer of squamous cells of epithelium
Risk: UVB exposure, arsenic exposure, fair complexion, radiation
Painless, well demarcated, scaly patch or plaque, erythematous, scaling
Tx: surgical excision (Mohs), radiation
5-10% mets
Basal cell carcinoma
Most common skin cancer
Pearly papule with telangiectasias, +/- rolled edges with ulceration
Tx: surgical excision (Mohs), radiation, cryotherapy
less than 0.1% met
Melanoma
Malignant melanocytes tumor - rapid spread
Risk: sun exposure, fair complexion, FHx, numerous nevi
Types:
Superficial spreading - MC, grows laterally before vertically
Acral lentiginous - least common, found on palms, soles, nail beds
Lengito maligna - slow growth, 10-50 yrs before vertical growth
Bx: atypical melanocytes with invasion of dermis
>0.76 mm risk mets
Tx: surgical excision
Insitu - 0.5 cm margin
less than 2 mm thick - 1 cm margin
>2 mm thick - 2 cm margin +/- LN dissection
Chemo/rad if mets
Mets -> lung, brain, GI tract
Melasma
Dark skin discoloration, in pregnant women and those taking OCPs or HRT
Minimizing sunlight exposure and opaque sunscreen - titanium dioxide or zinc oxide
Triple combo cream - tretinoin, hydroquinone, mid-potency topical steroid - flucinolone
Vitiligo
Sharply demarcated patches of complete depigmentation - due to loss of melanocytes
- Borders are hyperpigmented
- MC in acral areas, around body orifices
Skin texture is normal
Assoc with graves’ disease, autoimmune thyroiditis, pernicious anemia, T1DM, primary adrenal insufficiency, hypopituitarism, alopecia areata, autoimmune hepatitis
MC 20-30 yo
Tx: Sunscreen to minimize tanning Dyes and make up Topical mid-pot corticosteroids first line (low potency kids) Tacrolimus or pimecrolimus Psoralens (topical or PO) + UV light Surgical minigrafting Hydroquinone for depigmentation - last resort
Acanthosis nigricans
Brown to black velvety hyperpigmentation of the skin
Associated with T2DM, hyperinsulinemia and visceral malignancies
Tx underlying disorder
Tretinoin - topical
Calcipotriene - topical vit D analog
treatment for infantile hemangiomas
Uncomplicated - gradually resolve within the first two years of life, observation best treatment
Complicated - oral propranolol, systemic glucocorticoids, vincristine, interferon alpha
Alopecia areata
Asymptomatic, inflammatory, non-scarring areas a complete hair loss
Maybe precipitated by stress
Regrowth after first attack in 30% by 6 mo, 50% by 1 yr, 80% by 5 yr
R/o other cause - get syphilis screen, CBC, BMP, ESR, TSH, ANA
R/o trichotillomania
Tx: intralesional steroid injections topical corticosteroids Topical minoxidil Topical immunotherapy Topical anthralin Oral corticosteroids
telogen effluvium
diffuse stress related hair loss
tx: reassurance, stress avoidance
Androgenic alopecia
Hormonal and genetic causes
DHT causes follicular miniaturization -> replacement of terminal hairs by short, thin hairs
Tx: finasteride - 5a-reductase inhibitor
Topical minoxidil
