“Reactive” and Idiopathic Skin
Diseases
Rich Callahan MSPA, PA-C
Fletcher Allen Dermatology
Burlington, Vermont
ICM I – Summer 2009
Overview
• Erythema Multiforme (EM)
• Erythema Nodosum (EN)
• Stevens-Johnson Syndrome/Toxic
Epidermal Necrolysis (TEN)
• Urticaria/Angioedema
• Lichen Simplex Chronicus/Prurigo
Nodularis
• Lichen Planus
EM – What is it?
• An acute, common skin rash associated with a
number of causative factors, although 50% of the
time a precipitating cause is not found.
• Classified as a reactive, inflammatory process of
the skin, or “Hypersensitivity syndrome.”
• Reactive change in dermal vasculature with
overlying epidermal changes
EM – Epidemiology/Causative
Factors
• Can be caused by drugs, infections
(Herpes,) pregnancy, internal malignancy,
acute URI, atypical pneumonia
• ~50% idiopathic
• Mostly see in younger patients, most
common age range is 20-40 years
• I have seen several patients who develop
EM after HSV outbreaks (cold sores)
EM – Clinical Presentation
• Characteristic erythematous, target-shaped,
urticarial papules, vesicles and bullae
• Affects trunk, extremities, mucous membranes,
palms/soles.
• Lesions appear quickly in a symmetric pattern,
usually first on dorsal hands/feet, then migrating
along extensor extremities, then to trunk in severe
cases.
• Can be asymptomatic, pruritic or painful.
• Occassionally, will manifest only as oral bullae
and ulcerations.
EM – Clinical Presentation
• Eruption evolves over several days, may be
preceded by prodromal symptoms including
malaise, fever or burning/itching at sites where
EM will later develop.
• Presentation can be entirely non-diagnostic at first,
then later dx’ed as EM when classic “target
lesions” develop.
• Entire course of disease usually 1 month or less.
• Rarely life-threatening with extensive mucous
membrane involvement, patches of vesiculation,
etc
EM - Diagnosis
• EM is a clinical diagnosis based on patient history
and disease presentation.
• Skin biopsy seldom helpful in my experience as
histologic findings can be non-specific at early
stages of disease, which is when it tends to get
biopsied.
• Biopsy of target lesions generally diagnostic, but
seldom biopsied as is an easy clinical diagnosis by
that point!
EM - Treatment
• Mild cases do not require treatment.
• Moderate cases respond well to a 1-3 week
course of oral steroids (prednisone.)
• Severe cases treated with IV steroids.
• In recurrent cases with positive HSV
association, I have used prophylactic
therapy with oral antiviral meds (Valtrex)
with good success.
Erythema Nodosum – EN – What
is it?
• An acute panniculitis of the lower extremities
with diverse causes
• Considered a delayed hypersensitivity reaction to
a number of possible antigens, I.e., it is a reaction
to a concurrent disease or condition.
• Most common cause today is streptococcal
infection.
• Can be precipitated by drugs, infections,
sarcoidosis, misc. inflammatory disorders
EN - Causes
•
•
•
•
•
•
Infections
Bacterial
Fungal
Viral
GI parasites
Drugs (esp. OCP’s)
•
•
•
•
•
•
Cancer
Concomitant Disease
Sarcoidosis
IBD
Ulcerative Colitis
Crohn’s Disease
EN - Epidemiology
•
•
•
•
Women >> men. Female: Male ratio is 5:1
Peak ages of incidence are 18 – 35 years.
Extremely rare in the elderly.
Historically, much less common in the
modern area with advent of antibiotic drugs.
EN – Clinical Presentation
• Presents as development of painful red nodules,
patches and plaques, usually on lower legs, over a
period of 1-2 weeks.
• Often preceded by prodromal symptoms of fever,
malaise, arthritis and arthralgias.
• Individual lesions begin as reddish, swollen
papules on shins bilaterally, then grow into
violaceous, indurated, tender patches and plaques
which resolve in 1-2 weeks.
• Eruption can recur in crops for months to years.
EN - Treatment
• Usually resolves spontaneously w/o
treatment.
• Symptomatic relief with rest and/or
NSAID’s.
• SSKI (supersaturated potassium iodide.)
• Prednisone
• ID and treatment of precipitating cause if
possible.
Stevens-Johnson Syndrome/Toxic Epidermal
Necrolysis – What is it?
• Both names represent a spectrum of disease with
SJS being the less severe end.
• A life-threatening condition characterized by large
scale and widespread necrosis and detachment of
epidermis, affecting both skin and mucosal
surfaces of eyes (conjunctivae,) nares, mouth,
anorectal/genital areas.
• One of the few truly acute medical emergencies in
Dermatology.
SJS/TEN
• Pathophysiology not entirely understood, but
thought to be reaction in keratinocytes where cells
accumulate foreign antigen and are stimulated to
apoptosis (cell death) by T-cells.
• Large areas of epidermis become necrotic and
slough off in sheets
• Results in massive transcutaneous water loss and
usually secondary bacterial infection
SJS/TEN - Causes
• Most often caused by drugs, then infections, then
rarely by a malignancy.
• Drugs include: Sulfonamides, Bactrim/Septra,
Quinolones, Cephalosporins, acetaminophen,
phenobarbital, NSAID’s, cocaine, ginseng,
allopurinol, fluconazole, many others.
• Infections include influenza, HSV, Epstein-Barr
virus, Cat-Scratch disease, histoplasmosis
• Malignancies include carcinomas and lymphomas
SJS/TEN Spectrum of Disease
• Grade I - SJS: Less than 10% of Body
Surface Area (BSA) affected.
• Grade II - SJS/TEN Overlap: Between
10% and 30% BSA affected.
• Grade III – TEN: Greater than 30% BSA
affected.
SJS/TEN
Epidemiology/Morbidity/Mortality
• Usually seen in Caucasians, male:female ration is
2:1.
• Average patient is 20-40 years old, although
occasionally seen in infants/elderly.
• If BSA involvement 10% or less, mortality is 15% of cases. 30% or higher BSA involvement has
mortality rate between 25% and 35%
• Overall mortality for entire SJS/TEN spectrum of
disease is 15%
SJS/TEN – Clinical Presentation
• Clinically manifests as erythematous and purpuric
macules and target lesions, distributed over trunk,
palms, soles and mucosal areas. Blister formation
and sloughing/necrosis of skin follow.
• Nikolsky Sign: Pushing down on blisters causes
them to spread laterally with little resistance
• Skin rash preceded by cough/URI symptoms.
• Patients have fever, electrolyte imbalances,
eye/mucous membrane involvement, pain,
occassional lung involvement.
SJS/TEN – Clinical Presentation
• Mucosal lesions lead to widespread
epidermal sloughing and crust formation.
• Extensive disease can lead to scarring,
stricture formation and partial loss of
funcion of organ system involved.
• Eye involvement includes corneal
ulcerations and conjunctival injury which
can lead to scarring and blindness.
SJS/TEN - Treatment
• Most often a reaction to drugs, so look for
offending cause in all cases: Usually the newest
drug on a patient’s list, within 1 to 4 weeks of
starting it
• Treatments are supportive, although oral
prednisone is often used in an attempt to shorten
duration of illness.
• Other treatments include oral antihistamines,
lidocaine gargles, liquid/soft diet, Burrow’s
compresses, topical steroids to non-eroded areas,
ophthalmology consult, antibacterial therapy for
secondary infections.
Urticaria/Angioedema
• Urticaria presents as
groups of itchy,
pink/flesh-colored
wheals
• Caused by edema, or
fluid accumulation in
epidermis/superficial
dermis
• Papillary vascular
plexus
• Angioedema presents
as broad, poorlydefined areas of
swelling
• Caused by edema of
dermis and subcutis
• Deep vascular plexus
Urticaria/Angioedema
• Wide Variety of
• Physical Urticaria –
Causes:
Angioedema
• 50-60% of cases
• Infections
idiopathic
• Treatment usually
• Allergies
with antihistamines
• Drugs
and/or prednisone
• Contact urticaria
• Autoimmune and
immunologic mediated
LSC/Prurigo Nodularis
• Lichenification of skin
in direct reaction to
repeated rubbing and
scratching of skin
• Skin becomes
thickened with
accentuation of skin
markings
• Scratching becomes
pleasurable to patient
• Dome-shaped,
hyperpigmented
papules and nodules in
areas of lichenification
• Often deeply
excoriated
• Hyperplasia of
cutaneous nerves leads
to enhanced sensitivity
and pruritis
Lichen Planus (LP)
• Idiopathic eruption defined by the 4 P’s:
• Pruritic, purple, polygonal papules
• Tends to affect wrists, flexor extremities,
lumbar areas, genitals, mucosa
• Tends to last 6 months to one year
• Leaves behind deep, long-lasting
hyperpigmentation
• Presence of Wickham’s striae diagnostic