Hospital Dermatology

Hospital Dermatology: Erythema Multiforme, etc.

Erythema multiforme is an uncommon, self-limited disorder; a hypersensitivity response to certain infections and drugs

Stevens-Johnson Syndrome (SJS) is a more intense variant

Toxic epidermal necrolysis (TEN) is the most extreme variation which resembles burns

Characteristics of Erythema Multiforme, SJS, and TEN

	Erythema multiforme	Stevens-Johnson Syndrome	Toxic epidermal necrolysis
Incidence:	0.01%-0.1%	0.01%-0.1%	0.5-1.2 Cases per million
Age:	Children and young adults (<40 Yr)	Children and young adults (<40 Yr)	Any age, less common in children
Precipitants:	Herpes Simplex, other infections (mycoplasma), rarely drugs	Infections (mycoplasma), drugs (i.e.,sulfa)	Drugs (antibiotics, Nsaids etc.) role of Infections uncertain
Skin Findings:	Iris (target) lesions, fixed erythematous, macules, papules and plaques, blisters, acral distribution	Fixed erythematous macules, papule and plaques, iris lesions, blisters (bullae) and erosions, central distribution	Explosive erythematous macules, urticarial plaques, irregular iris lesions develop, coalesce, blister and desquamate
Mucosal Findings:	Minor - Occasionally oral ulcers	Prominent - Ulcers in two or more sites - photophobia, dysphasia, dysuria	Ulcers in two or more sites
Systemic Symptoms:	None	Fever, malaise	Fever, malaise
Cutaneous Symptoms:	None, pruritus, or burning	None, pruritus, or burning	Tenderness and pain: even before rash
Histology	Scattered necrotic keratinocytes, papillary dermal edema, perivascular lymphocytic infiltrate	Scattered necrotic keratinocytes, papillary dermal edema, perivascular lymphocytic infiltrate	Extensive keratinocyte necrosis (full thickness), No infiltrate or edema
Course	Self-limited, benign, recurring	Self-limited (3-6 Weeks), severe (fluid/electrolytes, infection)	Progressive, severe (fluid/electrolytes, infection)
Treatment	Bland emollients, anti-infectives, Acyclovir, antihistamines, oral care	Bland emollients, Anti-infectives (withdraw offending medication), corticosteroids controversial-no supportive studies demonstrate its efficacy.	Withdraw offending medication, bland emollients, anti-infectives (Staph early, Pseudomonas late), fluid and electrolyte replacement, monitor temperature, nutrition, hydrocolloid dressings vs Graft 0.5% silver nitrate, eye care, corticosteroids controversial
Complications:	None	Fluid/electrolyte abnormalities, kerato-conjunctivitis, blindness, urinary retention, hematuria, stricture (esophageal, urethral, vaginal, anal, lacrimal duct)	Keratoconjunctivitis, blindness, stricture, renal and respiratory failure, sepsis. Ocular sequelae occur in 35% of patients.
Iris Lesion	Classic	Irregular
Distribution	Acral	Central
Mortality:	0	< 5%	<25% (25-70% due to infection or fluid/electrolyte loss.

Erythroderma – exfoliative dermatitis

Diffuse Erythma and Scaling. Note: this is a description not a diagnosis.

Associated findings: Chills, Hypothermia, High out put Cardiac Failure, Lymphopenia, Neutropenia

Therapy must be directed toward resolving any of these findings as well as underlying skin disease.

Differential diagnosis: extensive; most likely to be Atopic Dermatitis, Psoriasis, Contact Dermatitis, Pityriasis Rubra Pilaris, Seborrheic keratitis

Dermatitis is responsible for 62.5% of erythroderma

differential diagnosis also includes Graft-versus Host Disease, Cutaneous T-Cell Lymphoma, Mycosis Fungoides/Sezary Syndrome, Early TEN, Toxic Shock Syndrome (Staph or Strep)

Mortality = 5-10%: mostly due to CHF, Lymphoma, Sepsis

Vasculitis

Segmental inflammation and necrosis of blood vessels Þ ischemia of tissue

The two most common mechanisms are direct injury to vessels by infectious pathogens and immune-mediated inflammation

Mechanism: cytokines released as result of triggering events, cause Increased expression of endothelial and leukocytic adhesion molecules which stimulates inflammatory leukocytes to release destructive enzymes.

Trigger factors:

(1) Immune complexes Þ macrophages Þ cytokines Þ etc.Þ Vasculitis

(2) Antineutrophilic cytoplasmic antibody Þ etc.Þ Vasculitis

(3) Pathogenic (abnormal) Tcell responses Þ Granulomas

Examples: Leukocytoclastic Vasiculitis, Polyarteritis Nodosa, Granulomatis Vasculitis, Giant cell Arteritis

Differential Diagnosis: Extravascular blood, intravascular blood, other pigments

Bottom line: to help a patient, need to consider all evidence and possibilities: Bugs, Drugs, Thugs and Other Organs