Dermatology Flashcards
Associated with asthma and allergic rhinitis
Erythema, crusts, fissures, pruritis, excoriations, lichenification
Chronic pruritic skin condition
Infants: Blisters, crusts, exfoliation (face, scalp, extremities),1st few months. Resolves by age 2
Adults: Dryness and thickening in antecubital and popliteal fossae, neck
Positive family history, worse in winter (dry weather)
Eczema (Atopic Dermatitis)
Delayed type hypersensitivity Poison ivy, poison oak, poison sumac (linear extension) Contact with metal jewelry (nickel) Hair dyes, detergents Erythema, pruritus, vesicles, bullae Blister fluid contains no antigen Corticosteroids for severe cases
Allergic Contact Dermatitis
Generalized dermatitis, diffuse, scaly, warm, erythematous, non-tender, pruritic
Leads to exfoliation
Most are secondary to underlying disease
Involves most or all of skin
Flares of pre-existing skin disease (psoriasis, atopic dermatitis etc.)
Differential: SSSS, EM, TEN ,TSS
Exfoliative Dermatitis
Response to drugs, chemicals, systemic disease or malignancy (lymphoma, leukemia)
May be acute, subacute or chronic
Typically males over 40
Complications are 2° to disruption of epidermis
Hypothermia, volume loss, electrolyte abnormalities, 2° skin infection
Important to diagnose underlying cause
Admit, IV, steroids for severe cases
Exfoliative Dermatitis
Chronic papulosquamous eruption
Due to more rapid cell cycle
Erythematous plaques with white (silver) scales
Extensor surfaces of elbows, knees, scalp, palms, soles
Pitting of the nails
May be accompanied by psoriatic arthritis
Treatment: steroids, tar, UV light, methotrexate
Psoriasis
White, yellow, waxy scales with erythema
Localized to hairy skin areas
Scalp, eyebrow, ear, axilla, groin (wherever
there are sebaceous glands)
Malassezia (a fungus) is associated
Not contagious
Frequent recurrences, worse in cold weather
May be severe or generalized in HIV positive patients
Treatment: Rotating antidandruff shampoos,
ketoconazole shampoo or cream; steroids are discouraged
Seborrheic Dermatitis (Dandruff)
Children, young adults, spring and fall
Etiology unknown
No epidemics, not contagious
Rash evolves over weeks
Herald patch: Single salmon-colored lesion with raised boarder on trunk, 1–5 cm
1-2 weeks after herald patch: Widespread eruption, pink maculopapular oval patches that follow the ribs (“Christmas tree” pattern)
Rule out syphilis (if clinically indicated), drug reaction
Treatment: Symptomatic, antihistamines
Resolution in 2-10 weeks
Pityriasis Rosea
Deposits of blood under skin Non-blanching Petechiae <3 mm, purpura >3 mm Non-palpable: Platelet disorder, thrombocytopenia Palpable purpura = Vasculitis Treatment: Antibiotics, steroids, plasmapheresis (depends on etiology)
Petechiae / Purpura
Diffuse pruritus, wheals, hives (superficial dermis)
Lesions move around within 24 hours
Etiology is unknown most of time
IgE → mast cells → histamine release
Usually self-limited
Treatment: Antihistamines, steroids, antipruritics, H2 blockers, epinephrine
Urticaria
Bradykinin-mediated ↑ Vasodilation ↑ Vascular permeability Edema of the deeper dermis Common cause: ACE inhibitors ACE inhibitors decrease metabolism of bradykinins Can occur early or late 2/3 occur in hours 1/3 in months to years
Angioedema (1)
Familial - associated with C1 esterase inhibitor deficiency
C1 esterase inhibitor inhibits complement cascade
Deficiency leads to increased bradykinin
Edema of face, extremities, bowel wall
Responds to fresh frozen plasma and C1 esterase inhibitor concentrate
Autosomal dominant (positive family history)
Angioedema
Infants, toddlers, elderly
Usually Group A Strep, occasionally Staph
Superficial cellulitis, lymphangitis
Localized (face, legs, ear)
Butterfly facial rash (warm and tender)
Raised, well demarcated border
Treatment: PCN, dicloxacillin, erythromycin
Erysipelas
Painful, non-ulcerative, violaceous nodules (localized vasculitis) on anterior tibia, arms, trunk
Looks like erythema, feels like nodes
EN is often a marker for systemic disease
Drug reaction (oral contraceptives, sulfa, PCN)
Systemic infection (TB, fungal)
Sarcoid
Inflammatory bowel disease (ulcerative colitis)
Malignancy (leukemia, lymphoma)
Most common in women 30-50
Resolves in 3-6 weeks
Treatment is directed at underlying disease
Erythema Nodosum (EN)
Consider in any acute, symmetrical eruption
Common: PCN, cephalosporins, sulfa
Usually disappears within 1-2 weeks
Immediate hypersensitivity: IgE (urticaria)
Delayed hypersensitivity: IgM (serum sickness)
Urticaria, morbilliform rash (discreet red-brown papules coalesce to erythema), erythema multiforme
Treatment: Discontinue drug, antihistamines, steroids
Complications: Stevens-Johnson syndrome (mucosal and cutaneous), Severe bullous (form can be fatal)
Drug Eruption
Minor (erythema multiforme) EM major (Stevens-Johnson) EM maximum (TEN)
Hypersensitivity reaction
Infection (Mycoplasma, Herpes), malignancy, drugs
Sulfa, oral hypoglycemics, anticonvulsants, PCN (memory aid: “SOAP”)
Palms, soles, extensor surfaces
“Bull’s eye” or “target” lesions
Treatment: Remove offending agents; symptomatic for minor forms; major forms may need resuscitation, ICU admission
Erythema Multiforme
Severe bullous form of EM, 10-30% of BSA, mucosal involvement, can be fatal
Bullous cutaneous lesions, mucositis, stomatitis, conjunctivitis, crusted nares
Children, adolescents, males
Serious, potentially fatal form of E. multiforme
Hypersensitivity reaction
Severe reaction to medication: Sulfonamides PCN, barbiturates, phenytoin, tetracycline, thiazides
Stevens-Johnson Syndrome
Erythema multiforme, Stevens-Johnson syndrome and TEN
Probably variants of the same disease process. The difference is in severity and body surface area affected
TEN affects >30% of BSA
Exposure to drugs, chemical agents, infections
Sulfa, PCN, barbiturates, phenytoin, allopurinol, NSAIDs
Mycoplasma, HSV
Toxic patient, large bullae, mucous membranes, widespread systemic manifestations
Toxic Epidermal Necrolysis (TEN) 1
Separation of dermal-epidermal junction
Nikolsky’s sign: Skin peels off with light pressure
Older age group has high mortality
Increased mortality from dehydration and 2° infection
Primary causes of death: Sepsis, pneumonia
Treatment: Admit to ICU
Toxic Epidermal Necrolysis (TEN)
Usually children <2 years old
Staph aureus exotoxin
Fever, scarlatiniform rash followed by exfoliation
Nikolsky’s sign: Skin peels off with light pressure
Antibiotics (vancomycin) indicated, but do not alter cutaneous disease
More favorable prognosis than TEN
Steroids are contraindicated
Staphylococcal Scalded Skin Syndrome
Painful intradermal bullae, 40-60 years old, possible autoimmune etiology
Associated with penicillamine, captopril, phenobarbital
Bullae on normal skin, often start in mouth
Mucus membranes are frequently involved
Blisters are fragile, break easily, leave red or crusted erosions
Small flaccid bullae erosions, ulcerations
Nikolsky sign positive (like TEN)
Can be lethal: Mortality due to secondary infection, dehydration
Treatment: Steroids, admission, biopsy
Pemphigus Vulgaris
Chronic benign bullous eruption. Autoimmune disease
Risk factors: Age > 60, female, malignancy, furosemide (Lasix)
Begins with urticarial lesions, then tense blisters up to 10 cm
Large bullae (2-5 cm) arise from erythematous skin
Mucus membranes infrequently involved
Nikolsky sign negative
IgE deposited on basement membrane
Course is usually benign. Mortality much less than in pemphigus
Bullous Pemphigoid
Most common skin malignancy Pearly, rolled border with central ulceration Not a metastasizing tumor Slow growing, usually head and neck Seen only where hair follicles exist Cure rate 100% if found early
Basal Cell Carcinoma
Increasing incidence
Ages 30-50
Risk factors: Adulthood, dysplastic nevi, family history of melanoma, fair skin, UV exposure, congenital nevi
Account for majority of skin cancer deaths
Sun exposed areas (head, neck, trunk)
The greater the depth, the worse the prognosis
Metastases are common
Malignant Melanoma
Second most common cutaneous malignancy
Common in elderly males, fair skin, sun
exposure
Face, lips, ears, tongue, hands
Rapid growth, central ulcer, raised and indurated border
Metastases occur early
Treatment: Excisional surgery, radiationSquamous Cell Carcinoma
Tinea capitis (scalp) and tinea barbae (beard)
Bald, broken hair
Scaly patch
Edematous nodules and pustules (kerion)
Tinea corporis (ringworm)
Non-hairy parts of the body, outward spreading, annular lesion, clear center
Tinea pedis (athlete’s foot)
Tinea cruris (jock itch)
Groin and inner thigh (sharp demarcation)
Scrotum not involved
Causes: Trichophyton, Microsporum, Epidermophyton
Treatment: Antifungal (topical or oral)
Tinea (Dermatophytosis
Hypopigmented or hyperpigmented circular, scaly patches
Poor hygiene, moisture
Malassezia fungus
Treatment: Selenium shampoo, ketoconazole shampoo or cream
Pityriasis (Tinea) Versicolor
Pathogenic spirochete
Reservoirs: Rats, cattle, pigs, dogs
Skin contact with urine of infected animal
Contaminated water
Hepatitis, nephritis, meningitis, coagulopathy
Weil’s disease (severe form): Jaundice, subconjunctival hemorrhage, hepatitis, DIC
Risk of death from hepatorenal failure
Diagnosis by serology
Treatment: Pen G, tetracycline, doxycycline
Leptospirosis
