43: Erythema Multiforme Flashcards
What is Erythema Multiforme (EM) and how is it classified?
Erythema Multiforme (EM) is an acute mucocutaneous syndrome characterized by distinctive clinical patterns that are mild and self-limited, with a risk of relapse. It is classified into two categories based on mucous membrane involvement: EM minor (EMm), which involves only skin and lips, and EM major (EMM), which involves mucous membranes.
What are the epidemiological characteristics of Erythema Multiforme?
Erythema Multiforme (EM) is common with an unknown true incidence. EM minor (EMm) is more common than EM major (EMM), prevalent in adolescents and young adults, with a male-to-female ratio of approximately 2:3. Recurrence rates are 10% for EMM and 30% for EMm, particularly in HSV-associated cases.
What are the clinical features and history associated with Erythema Multiforme?
Most cases of Erythema Multiforme (EM) have no prodromal symptoms; if present, they are mild. In EMM, fever may exceed 38.5°C in about 1/3 of cases. A review of events in the preceding 3 weeks should look for signs of HSV or respiratory infections.
What are the cutaneous features of Erythema Multiforme?
The cutaneous features of Erythema Multiforme (EM) include abrupt eruption of lesions, mostly symmetric distribution, centripetal spread, and a predilection for sun-exposed sites. Lesions are often asymptomatic, with occasional burning and itching.
What subtype of EM involves only the skin and lips?
This represents EM minor (EMm), where only the skin and lips are involved.
What is the preferred term for lesions that involve mucous membranes?
The preferred term for this presentation is mucosal erythema multiforme (EMM).
What subtype of EM involves typical targets on the extremities?
This represents typical erythema multiforme major (EMM), which involves typical targets on the extremities.
What is the typical distribution pattern of EM lesions?
EM lesions are often symmetric and appear on extensor surfaces (hands, feet, elbows, knees), face, and neck, with a predilection for sun-exposed sites.
What subtype of EM is associated with Mycoplasma pneumoniae?
This is atypical erythema multiforme (EMM), which is more frequently associated with Mycoplasma pneumoniae.
What is the average interval between HSV infection and the onset of EM lesions?
The average interval between HSV infection and the onset of EM lesions is 7 days, with a range of 2-17 days.
What is the typical time frame for the appearance of EM lesions?
EM lesions typically appear abruptly, with most patients developing all lesions within 3 days.
What phenomenon explains the distribution of EM lesions?
The distribution of EM lesions is explained by the Koebner phenomenon and their predilection for sun-exposed sites.
What distinguishes Erythema Multiforme minor (EMm) from Erythema Multiforme major (EMM)?
EMm involves only the skin and lips, while EMM affects mucous membranes as well. EMm is characterized by a milder clinical pattern, whereas EMM presents with more severe symptoms due to mucosal involvement.
What is the significance of the association between herpes simplex virus (HSV) and recurrent Erythema Multiforme?
In over 70% of recurrent Erythema Multiforme cases, an episode of recurrent HSV infection precedes the lesions, suggesting a strong link between HSV and the exacerbation of EM.
How does Atypical Erythema Multiforme differ from Typical Erythema Multiforme?
Atypical Erythema Multiforme presents with more extensive and larger targets, often involving the skin around the mouth and eyes, while Typical Erythema Multiforme typically targets the extremities.
What are the common cutaneous features observed in patients with Erythema Multiforme?
Common cutaneous features include abrupt eruption of lesions, symmetric distribution, centripetal spread, Koebner phenomenon, and an asymptomatic nature.
What factors contribute to the epidemiology of Erythema Multiforme?
Erythema Multiforme is most prevalent in adolescents and young adults, with a male-to-female ratio of approximately 2:3. Recurrence rates are higher in EMm compared to EMM.
What are the typical characteristics of a target lesion in Erythema Multiforme?
Target lesions are highly regular, circular, wheal-like erythematous papules or plaques that persist for 1 week or longer, with a size range of few mm to 3 cm.
What noncutaneous features are commonly associated with Erythema Multiforme?
Mucosal lesions occur in 70% of patients, often limited to the oral cavity, with a predilection for lips and nonattached gingivae.
What are the common complications associated with Erythema Multiforme?
Complications include impaired alimentation and reflex anuria, though severe ocular lesions are rare.
What is the primary etiology and pathogenesis of Erythema Multiforme?
Most cases are related to infection, primarily HSV in recurrent cases, with M. pneumoniae as the second major cause.
What diagnostic methods are used for confirming Erythema Multiforme related to M. pneumoniae?
PCR of throat swabs/bronchopulmonary lavage is the most sensitive for confirmation. Serology is diagnostic in the presence of IgM or IgA antibodies.
How long do target lesions in Erythema Multiforme typically persist?
These lesions typically persist for 1 week or longer.
What is the size range of infiltrated papules in Erythema Multiforme?
The size range of these lesions is a few millimeters to 3 cm.
What is the most likely diagnosis for a patient with circular lesions and a dusky central disk?
The most likely diagnosis is erythema multiforme (EM) with typical target lesions.
What is the likely cause of erythema multiforme in a patient with fever and oral erosions?
The likely cause is Mycoplasma pneumoniae-associated erythema multiforme (EM), more frequent in children and adolescents.
What diagnostic tests can confirm the association with M. pneumoniae?
PCR of throat swabs or bronchopulmonary lavage is the most sensitive test, along with serology showing IgM or IgA antibodies.
What is the most common infectious cause of EM in children?
The most common infectious cause of EM in children is Mycoplasma pneumoniae.
Why is a true association between drugs and EM considered unlikely?
A true association between drugs and EM is unlikely because most cases attributed to drugs are actually EM imitators.
What is the term for lesions that include a central bulla and a marginal ring of vesicles?
This specific lesion type is called the ‘Herpes Iris of Bateman.’
How do EM lesions differentiate from SJS or TEN?
EM lesions are infiltrated papules, whereas SJS/TEN lesions are macules.
What is the likely cause of urinary retention in a patient with genital erosions?
The likely cause of urinary retention is pain from the genital erosions, leading to reflex urinary retention.
What are the three concentric components of a typical target lesion?
The three concentric components are: 1) dusky central disk or blister, 2) infiltrated pale ring, and 3) erythematous halo.
What areas are typically spared in mucosal involvement of EM?
The hard palate and attached gingivae are usually spared in mucosal involvement of EM.
What percentage of patients with Erythema Multiforme (EM) experience mucosal lesions?
Mucosal lesions occur in 70% of patients, often limited to the oral cavity.
What areas are commonly affected by Erythema Multiforme (EM)?
There is a predilection for lips (both cutaneous and mucosal sides), nonattached gingivae, and ventral tongue.
Which areas are usually spared in Erythema Multiforme (EM)?
Hard palate and attached gingivae are usually spared.
What clinical features may be present in Erythema Multiforme (EM)?
Erosions, fibrinous deposits, and occasional intact vesicles and bullae may be present.
How does Erythema Multiforme (EM) affect the throat and respiratory tract?
It rarely affects the throat, larynx, trachea, and bronchi.
What ocular symptoms may occur in children with Erythema Multiforme (EM)?
Eyes may show pain and bilateral conjunctivitis, especially in children with M. pneumoniae-associated EM.
What complications are associated with Erythema Multiforme (EM)?
Complications include impaired alimentation due to painful mouth erosions and rare reflex anuria and severe ocular lesions.
What is the primary etiology of Erythema Multiforme (EM)?
Most cases are related to infection, primarily HSV, especially in recurrent cases.
How soon do Erythema Multiforme (EM) eruptions typically begin after HSV eruptions?
EM eruptions typically begin 7 days after HSV eruptions.
What is the second major cause of Erythema Multiforme (EM) in children?
M. pneumoniae is the second major cause, particularly in children.
What are the common conditions associated with Erythema Multiforme (EM)?
Conditions commonly associated with EM include Herpes simplex virus, Mycoplasma pneumoniae, Epstein-Barr virus, Orf, Parvovirus B19, Hepatitis B, and Hepatitis C.
What is the typical course of Erythema Multiforme (EM)?
The course is mild, subsiding within 1-4 weeks, with complete recovery expected.
What is the mean number of attacks per year for patients with Erythema Multiforme (EM)?
The mean number of attacks is 6 per year (range 2-36).
What is the typical duration of Erythema Multiforme (EM)?
The mean total duration is 6-9 years, with 33% of cases persisting for more than 10 years.
What management strategies are recommended for Erythema Multiforme (EM)?
Management includes systemic corticosteroids, anti-HSV drugs (ineffective for established EM), symptomatic treatment for M. pneumoniae, topical treatments, ocular care, and amniotic membrane grafting for severe cases.
What preventive measures can reduce recurrences of Erythema Multiforme (EM)?
Preventive measures include continuous therapy with oral anti-HSV drugs, topical acyclovir therapy (ineffective), and other treatments like azathioprine and thalidomide.
What is the key histopathological feature in early Erythema Multiforme (EM)?
The key histopathological feature is lymphocytes at the dermoepidermal junction (DEJ) with exocytosis to the epidermis and satellite necrosis.
What is the typical histopathological finding in advanced Erythema Multiforme (EM)?
In advanced EM, subepidermal blister formation and prominent melanophages are typical findings.
What supportive treatments can be provided for painful mouth erosions in Erythema Multiforme (EM)?
Supportive treatments include liquid antacids, topical glucocorticoids, and local anesthetics.
What preventive measures can help avoid residual eye scarring in Erythema Multiforme (EM)?
Ocular lubricants and topical steroids, as recommended by an ophthalmologist, can help prevent residual eye scarring.
What alternative treatments could be considered for persistent Erythema Multiforme (EM)?
Alternative treatments include azathioprine, mycophenolate mofetil, or thalidomide.
What diagnostic test should be performed for a patient with Erythema Multiforme (EM) presenting with fever and cough?
A chest X-ray and PCR assay for M. pneumoniae should be performed.
What are the key clinical features suggesting a diagnosis of Erythema Multiforme (EM)?
Key features include lymphocytes at the DEJ, satellite necrosis, spongiosis, and absence of antidesmoplakin antibodies.
What is the approach to a patient with Erythema Multiforme (EM) regarding hospitalization?
Assess if it is EM, determine hospitalization needs, and identify the probable cause.
What are the differential diagnoses of Erythema Multiforme (EM)?
Differential diagnoses include Urticaria, Maculopapular drug eruption, Lupus erythematosus, Paraneoplastic pemphigus, Cicatricial pemphigoid, Antimicrobial EM major, Stevens-Johnson syndrome, and Sweet syndrome.
What is Urticaria?
Annular, circinate, blanching erythema with transient lesions (individual lesions last <24h).
More acute than EM.
What characterizes Maculopapular drug eruption?
Widespread polymorphous, targetoid lesions, macules, and papules. Most often nonspecific.
Rare (IP) and subacute.
What is Lupus erythematosus (‘Rowell syndrome’)?
Characterized by lesions on the face and trunk with interface dermatitis.
Possible (mouth) and subacute.
What are the features of Paraneoplastic pemphigus?
Large targetoid lesions and annular plaques with a positive Nikolsky sign.
Always tends to be severe, chronic.
What is Cicatricial pemphigoid?
Bullae and crusts in different stages with subepidermal blister and positive DIF.
Possible in BP (IP) in linear dermatosis, chronic for relapsing.
What defines Antimicrobial ‘EM major’?
Widespread small blisters with basal acantholysis and positive DIF.
Contact, antibodies present, acute relapsing.
What is Stevens-Johnson syndrome?
Widespread small blisters with atypical targets, typically confluent.
Contact, acute.
What characterizes Sweet syndrome (acute febrile neutrophilic dermatosis)?
Erythematous papules and succulent plaques with spongiosis and subcorneal vesicles.
Rare, neutrophilia, acute.
What is the first step in diagnosing suspected Erythema Multiforme (EM)?
Initial assessment to determine if the patient has transient lesions, widespread erythema, mucous membrane erosions, or blisters.
What to do if uncertain about EM diagnosis?
Consider a biopsy for immunofluorescence and serum antibodies.
How to assess the need for hospitalization in EM?
Assess if hospitalization is required based on the patient’s condition.
What to investigate as a probable cause of EM?
Check for a history of recurrent herpes, or consider Mycoplasma pneumoniae-related EM if there’s a cough or upper respiratory tract infection.
What to consider for patients with frequent recurrences of EM?
Consider anti-HSV prophylaxis in the absence of clinical herpes.
66% of EM patients have HLA-_____ allele.
DQB1∗0301
Atypical EMM, with more extensive distribution of giant larger targets, occasionally involves the skin around the mouth and the eyes, resulting in _____ facies.
clown-like
_____ age and _____ infection are infrequent association with atypical EMM.
younger
Mycoplasma pneumoniae
Highest incidence of EM was found in _____ and _____.
male children
young adults
Recurrence happens in about _____% of patients with EMM and up to _____% in EMm, more frequently, but not exclusively, in _____-associated cases.
10%
30%
HSV
