46: Erythema Annulare Centrifugum and Other Figurate Erythemas

Question 1

What are the clinical features of Erythema Annulare Centrifugum (EAC)?

Answer 1

EAC presents as skin papules that expand centrifugally, forming annular or polycyclic plaques with central clearing. The superficial variant shows slightly elevated lesions with desquamation at the inner margin, known as ‘Trailing scale’. The deep variant has indurated lesions with a firm border, often without prominent scaling. The most common symptom is pruritus, although lesions can be asymptomatic.

Question 2

What is the etiology and pathogenesis of Erythema Annulare Centrifugum (EAC)?

Answer 2

The etiology of EAC is not fully understood but is suggested to be a hypersensitivity reaction to an antigen. It has been linked to cutaneous or systemic infections, malignancy, drugs, and pregnancy.

Question 3

What are the common risk factors associated with Erythema Annulare Centrifugum (EAC)?

Answer 3

Risk factors for EAC include infections (e.g., Tinea Pedis, Molluscum Contagiosum, Herpes zoster), malignancies (e.g., non-Hodgkin lymphoma, acute myelogenous leukemia), medications (e.g., Finasteride, azacitidine, pegylated interferon-alpha), pregnancy (especially during the second to third trimesters), and other systemic diseases.

Question 4

What are the common sites of involvement for Erythema Annulare Centrifugum (EAC)?

Answer 4

The most frequent sites of involvement for EAC are the buttocks, thighs, and trunk. Upper extremities and head and neck involvement are less common.

Question 5

What is the typical course of Erythema Annulare Centrifugum (EAC) in pregnant women?

Answer 5

In pregnant women, EAC tends to occur during the second to third trimesters and typically remits spontaneously around the time of delivery without recurrence.

Question 6

What is the most likely diagnosis for a patient with annular plaques on the thighs and trunk, and what are the two histologic variants?

Answer 6

The most likely diagnosis is erythema annulare centrifugum (EAC). The two histologic variants are: 1) Superficial type, which shows epidermal changes like parakeratosis and spongiosis, and 2) Deep type, which lacks epidermal changes but shows perivascular infiltrates in both upper and lower dermis.

Question 7

What is the likely condition for a pregnant woman in her third trimester with annular lesions on her trunk?

Answer 7

The likely condition is erythema annulare centrifugum (EAC). In pregnant women, EAC tends to occur during the second to third trimesters and typically remits spontaneously around the time of delivery without recurrence.

Question 8

What is the likely diagnosis for a patient with a history of non-Hodgkin lymphoma who develops annular erythematous lesions?

Answer 8

The likely diagnosis is paraneoplastic erythema annulare centrifugum. The underlying mechanism is thought to be a hypersensitivity reaction to tumor antigens.

Question 9

What condition should be considered for a patient with annular lesions and a history of taking finasteride?

Answer 9

Erythema annulare centrifugum (EAC) should be considered. Other drugs associated with EAC include azacitidine, pegylated interferon-alpha, ribavirin, rituximab, ustekinumab, amitriptyline, and gold sodium thiomalate.

Question 10

What condition should be considered for a patient with annular lesions and a history of molluscum contagiosum?

Answer 10

Erythema annulare centrifugum (EAC) should be considered. The suggested etiology is a hypersensitivity reaction to an antigen, possibly linked to the molluscum contagiosum infection.

Question 11

What are the most common sites of involvement for erythema annulare centrifugum?

Answer 11

The most common sites of involvement for erythema annulare centrifugum are the buttocks, thighs, and trunk.

Question 12

Is residual scarring common in erythema annulare centrifugum?

Answer 12

Residual scarring is uncommon in erythema annulare centrifugum, although postinflammatory hyperpigmentation may occur after lesions resolve.

Question 13

What is the most common cutaneous infection associated with erythema annulare centrifugum?

Answer 13

The most common cutaneous infection associated with erythema annulare centrifugum is superficial dermatophyte infection, such as tinea pedis.

Question 14

What is the most common symptom associated with erythema annulare centrifugum?

Answer 14

The most common symptom associated with erythema annulare centrifugum is pruritus, although it is often asymptomatic.

Question 15

What variant of erythema annulare centrifugum is likely if a patient has lesions with prominent scaling at the inner margin?

Answer 15

The superficial variant of erythema annulare centrifugum is likely, as it demonstrates prominent scaling at the inner margin, also referred to as ‘trailing scale.’

Question 16

How do the clinical features of Erythema Annulare Centrifugum (EAC) differ between the superficial and deep variants?

Answer 16

EAC presents as skin papules that expand centrifugally, forming annular or polycyclic plaques with central clearing.

• Superficial Variant: Lesions are slightly elevated and demonstrate desquamation at the inner margin, known as ‘Trailing scale.’
• Deep Variant: Lesions have an indurated, firm border and often do not exhibit prominent scaling.
• Common Symptom: Pruritus, although lesions can be asymptomatic.

Question 17

What is the primary method for diagnosing Erythema Annulare Centrifugum (EAC)?

Answer 17

The diagnosis of EAC is primarily a clinical diagnosis. Histopathologic examination can help differentiate EAC from other conditions that cause annular lesions and confirm the diagnosis.

Question 18

What are the two distinct histologic patterns of Erythema Annulare Centrifugum (EAC)?

Answer 18

The two distinct histologic patterns of EAC are:
1. Superficial type: Epidermal changes include parakeratosis, hyperkeratosis, spongiosis, and/or vacuolar degeneration, with perivascular infiltrates more prominent in the upper dermis.
2. Deep type: Epidermal changes are absent or minimal, with mild edema in the papillary dermis and perivascular infiltrates involving vascular plexuses in both upper and lower dermis.

Question 19

What is the average duration of continuous lesions in Erythema Annulare Centrifugum?

Answer 19

The average duration of continuous lesions of EAC is approximately 4.75 months. Deep-type lesions tend to be longer lasting, while superficial-type lesions have a higher recurrence rate.

Question 20

What are the management options for symptomatic Erythema Annulare Centrifugum (EAC)?

Answer 20

Management options for symptomatic EAC include topical corticosteroids, topical vitamin D analogs, antihistamines if there is associated pruritus, systemic corticosteroids which can clear lesions but may lead to rebound recurrence, and antifungals and antibiotics such as fluconazole, erythromycin, and metronidazole.

Question 21

What is Erythema migrans and its association with Lyme borreliosis?

Answer 21

Erythema migrans is an annular erythema that represents an early cutaneous manifestation of Lyme borreliosis, an infection caused by the spirochete Borrelia burgdorferi, transmitted through the bite of Ixodes ticks.

Question 22

What is the epidemiology of Erythema migrans and Lyme disease?

Answer 22

Erythema migrans and Lyme disease are seen worldwide, with larger prevalence in parts of North America, central and eastern Europe, and eastern Asia. Most cases occur during June, July, and August, with a bimodal distribution of incidence, peaking between the ages of 5 and 19 years and 55 to 69 years.

Question 23

What are the three stages of Lyme disease?

Answer 23

1. Early localized disease
2. Early disseminated disease
3. Chronic disease

Question 24

What is the hallmark cutaneous finding of early localized Lyme disease?

Answer 24

An erythematous expanding annular plaque with a central area of clearing, often described as a ‘Bull’s-eye’ lesion.

Question 25

What are common symptoms associated with early localized Lyme disease?

Answer 25

Common symptoms include warmth, pruritus, and pain. In some cases, it can be asymptomatic or vesicular.

Question 26

How does erythema migrans typically present in terms of lesion growth?

Answer 26

Erythema migrans lesions grow centrifugally and can grow at a rate of up to 3 cm per day. The mean diameter of lesions is typically between 10 to 16 cm.

Question 27

What is the minimum time a tick must be attached for bacteria to be transmitted?

Answer 27

Ticks must be attached for at least 24 hours before bacteria is transmitted.

Question 28

What are some noncutaneous findings associated with early Lyme disease?

Answer 28

Noncutaneous findings include regional lymphadenopathy, arthralgias, arthritis, myositis, pancarditis, facial palsy, conjunctivitis, and hepatitis.

Question 29

What complications can arise from untreated Lyme disease?

Answer 29

Complications can include progression to the second stage of Lyme disease, which involves widespread spirochete dissemination with neurologic, rheumatologic, and other systemic manifestations.

Question 30

What is the minimum duration of tick attachment required for transmission of Borrelia burgdorferi?

Answer 30

The tick must be attached for at least 24 hours for transmission of Borrelia burgdorferi.

Question 31

What complications can arise from untreated Lyme disease?

Answer 31

Complications can include progression to the second stage of Lyme disease, which involves widespread spirochete dissemination with neurologic, rheumatologic, and cardiac involvement. The third stage may involve persistent neuroborreliosis, severe erosive arthritis, and acrodermatitis chronica atrophicans.

Question 32

What is the role of OspC in the pathogenesis of Lyme disease?

Answer 32

OspC is thought to bind to Salp15, a tick salivary protein, which inhibits components of the host immune system, facilitating the transmission of the bacteria.

Question 33

What are the risk factors for contracting Lyme disease?

Answer 33

Risk factors include spending time outdoors in endemic areas and a lack of protective clothing.

Question 34

What is the two-step process for laboratory testing to support the diagnosis of Lyme disease?

Answer 34

1. Enzyme immunoassay or indirect immunofluorescence assay is performed to detect antibodies. 2. If positive or equivocal, a western blot analysis is performed to confirm the diagnosis if positive.

Question 35

What is the likely diagnosis for a patient with an annular erythematous plaque with central clearing after a tick bite?

Answer 35

The likely diagnosis is erythema migrans, and the causative organism is Borrelia burgdorferi.

Question 36

What is the typical mean diameter of erythema migrans lesions?

Answer 36

The typical mean diameter of erythema migrans lesions is 10 to 16 cm, depending on the site of involvement.

Question 37

What stage of Lyme disease is indicated by erythema migrans with systemic symptoms like facial palsy and arthritis?

Answer 37

This is the early disseminated stage of Lyme disease. Potential complications if untreated include persistent neuroborreliosis, severe erosive arthritis, and acrodermatitis chronica atrophicans.

Question 38

What is the next step in laboratory testing for a patient with a positive enzyme immunoassay for Lyme disease?

Answer 38

The next step is to perform a Western blot analysis to confirm the diagnosis.

Question 39

What is the typical time frame for the appearance of erythema migrans lesions after tick detachment?

Answer 39

Erythema migrans typically appears approximately 7 to 14 days after tick detachment, with a range of 3 to 30 days.

Question 40

What are common sites for primary lesions of erythema migrans?

Answer 40

Common sites for primary lesions of erythema migrans include the trunk, axillae, groin, and popliteal fossae.

Question 41

Is a vesicular lesion a common presentation of erythema migrans?

Answer 41

While erythema migrans is typically an erythematous annular plaque, it can occasionally present as a vesicular lesion.

Question 42

What do regional lymphadenopathy and arthralgias indicate in a patient with erythema migrans?

Answer 42

These symptoms are indicative of early Lyme disease, which can include regional lymphadenopathy, arthralgias, and other systemic manifestations.

Question 43

What are the potential neurologic complications in the chronic stage of untreated Lyme disease?

Answer 43

Potential neurologic complications in the chronic stage of untreated Lyme disease include persistent neuroborreliosis.

Question 44

Why should Western blot analysis not be performed without a prior positive or equivocal antibody test?

Answer 44

Western blot analysis should not be performed without a prior positive or equivocal antibody test due to the risk of false-positive results.

Question 45

What are the three stages of Lyme disease and their characteristics?

Answer 45

1. Early localized disease: Characterized by an erythematous expanding annular plaque with a central area of clearing, often described as a 'Bull's-eye' lesion. Symptoms may include warmth, pruritus, and pain. 2. Early disseminated disease: Occurs if untreated, leading to widespread spirochete dissemination with potential neurologic, rheumatologic, and cardiac involvement. 3. Chronic disease: Involves persistent neuroborreliosis, severe erosive arthritis, and acrodermatitis chronica atrophicans.

Question 46

What are the common cutaneous findings associated with early Lyme disease?

Answer 46

- Erythema migrans: An expanding annular plaque at the tick bite site, characterized by a central area of clearing. - Symptoms: Warmth, pruritus, and pain; can be asymptomatic or vesicular. - Lesion growth: Can grow at a rate of up to 3 cm per day, with diameters ranging from 10 to 16 cm depending on the site.

Question 47

What is the clinical significance of tick attachment duration in the transmission of Lyme disease?

Answer 47

Ticks must be attached for at least 24 hours before bacteria is transmitted. Erythema migrans typically occurs 7 to 14 days after tick detachment, with a range of 3 to 30 days.

Question 48

What is the laboratory testing process for diagnosing Lyme disease?

Answer 48

1. Enzyme immunoassay or indirect immunofluorescence assay: Performed to detect antibodies. 2. If positive or equivocal, a western blot analysis is performed to confirm the diagnosis. ## Footnote Western blot should not be performed without a positive or equivocal antibody test due to the risk of false-positive results.

Question 49

What is the clinical course and prognosis of Erythema migrans?

Answer 49

Erythema migrans can present with a single lesion or progress to multiple lesions as the infection with B. burgdorferi becomes disseminated. Lesions often resolve after weeks to months.

Question 50

What are the common antibiotics used for the treatment of Lyme disease in its early stages?

Answer 50

The most common antibiotics used are: 1. Doxycycline 2. Amoxicillin 3. Cefuroxime ## Footnote Empiric antibiotic treatment is not recommended.

Question 51

What is Erythema marginatum and its association with rheumatic fever?

Answer 51

Erythema marginatum rheumaticum is an annular, erythematous eruption seen in a minority of patients with acute rheumatic fever. It is one of the major criteria for diagnosing rheumatic fever, which also includes carditis, migratory polyarthritis, Sydenham chorea, and subcutaneous nodules.

Question 52

What is the epidemiology of Erythema marginatum in relation to acute rheumatic fever?

Answer 52

ARF occurs as a complication of an antecedent pharyngeal infection with group A beta-hemolytic Streptococcus, seen in approximately 3% of untreated infections. Erythema marginatum is seen in fewer than 10% of patients with ARF, occurring more often in children than in adults, with a peak age of onset between 5 and 15 years.

Question 53

How do the clinical features of Erythema marginatum present?

Answer 53

Erythema marginatum classically presents as erythematous macules that spread to become annular or polycyclic patches or plaques. As the lesions expand centrifugally, there can be a central area of clearing, and the borders of the lesions are often well demarcated.

Question 54

What is the management approach for erythema marginatum associated with acute rheumatic fever?

Answer 54

- No intervention is necessary apart from the treatment of the underlying acute rheumatic fever (ARF). - Lesions may resolve spontaneously after treatment of ARF.

Question 55

What is the epidemiology of erythema gyratum repens?

Answer 55

- Approximately 70-80% of cases are associated with malignancy (lung, breast, esophagus, and stomach neoplasms). - It is thought to primarily affect adults due to its link to malignancies.

Question 56

What are the clinical features of erythema gyratum repens?

Answer 56

- Features multiple, erythematous, annular lesions that advance at a rapid rate of up to 1 cm per day. - Lesions form concentric rings that impart a 'wood-grain' pattern. - The onset of lesions can occur from 1 year before to 1 year after the diagnosis of malignancy. - Additional associated cutaneous findings may include ichthyosis and palmoplantar keratoderma.

Question 57

What laboratory tests can be used to diagnose acute rheumatic fever?

Answer 57

- Diagnosis is clinical, based on the appearance of typical cutaneous findings and a history of acute rheumatic fever. - Laboratory testing can include: 1. Positive throat culture 2. Positive rapid streptococcal antigen test 3. Presence of antistreptococcal antibodies such as: - antistreptolysin O antibody - antideoxyribonuclease B - Streptokinase - antihyaluronidase

Question 58

What are the typical locations of erythema marginatum lesions in acute rheumatic fever?

Answer 58

Erythema marginatum lesions typically occur on the trunk, axillae, and proximal extremities, and they usually spare the face.

Question 59

Where are subcutaneous nodules typically located in acute rheumatic fever, and are they painful?

Answer 59

Subcutaneous nodules are typically located over bony prominences such as the wrists, elbows, knees, and ankles. They are usually painless.

Question 60

What does a positive antistreptolysin O antibody test indicate?

Answer 60

A positive antistreptolysin O antibody test indicates a recent group A beta-hemolytic streptococcal infection, which is associated with acute rheumatic fever.

Question 61

How many major criteria are required for the diagnosis of acute rheumatic fever?

Answer 61

The diagnosis of acute rheumatic fever requires 2 major criteria or 1 major and 2 minor criteria.

Question 62

What is the typical clinical course of erythema marginatum lesions?

Answer 62

Erythema marginatum lesions tend to appear and disappear and may become more evident with hot showers or baths.

Question 63

What are the clinical features and typical locations of lesions associated with acute rheumatic fever?

Answer 63

- Lesions are often asymptomatic and have a predilection for the trunk, axillae, and proximal extremities, typically sparing the face. - Lesions tend to appear and disappear, becoming more evident with hot showers or baths. - Subcutaneous nodules occur over bony prominences (e.g., wrists, elbows, knees, ankles) and are usually painless in longstanding disease.

Question 64

What is the significance of erythema marginatum in the context of acute rheumatic fever?

Answer 64

Erythema marginatum is a cutaneous finding that represents one of the major criteria for diagnosing acute rheumatic fever. It often occurs in conjunction with acute carditis and is characterized by its migratory nature, typically involving the large joints, carditis, valvulitis, and other systemic symptoms.

Question 65

How does the clinical course and prognosis of lesions associated with acute rheumatic fever manifest after treatment?

Answer 65

The clinical course of lesions associated with acute rheumatic fever follows an indolent pattern that is independent of the underlying condition.

Question 66

What is a cutaneous finding that represents a major criterion for diagnosing acute rheumatic fever?

Answer 66

It is characterized by its migratory nature, typically involving large joints, carditis, valvulitis, and other systemic symptoms.

Question 67

How does the clinical course of lesions associated with acute rheumatic fever manifest after treatment?

Answer 67

The clinical course follows an indolent pattern that is independent of the underlying condition. Lesions may persist and typically resolve spontaneously without further intervention.

Question 68

What are the key diagnostic criteria for erythema gyratum repens?

Answer 68

Erythema gyratum repens is characterized by multiple, erythematous, annular lesions that advance rapidly, forming concentric rings with a 'wood-grain' pattern.

Question 69

What percentage of erythema gyratum repens cases are associated with malignancy?

Answer 69

Approximately 70-80% of cases are associated with malignancy, primarily affecting adults.

Question 70

What laboratory tests are useful in diagnosing acute rheumatic fever?

Answer 70

Laboratory tests can include positive throat culture for streptococcus, positive rapid streptococcal antigen test, and presence of antistreptococcal antibodies.

Question 71

What is the suggested etiology of Erythema Gyratum Repens?

Answer 71

It is suggested to occur as an immune reaction caused by the cross-reaction between tumor antigens.

Question 72

How is Erythema Gyratum Repens diagnosed?

Answer 72

It can usually be diagnosed based on clinical appearance, with the presence of a known malignancy supporting clinical suspicion.

Question 73

What are the management strategies for Erythema Gyratum Repens?

Answer 73

Management strategies include symptomatic relief with topical corticosteroids and resolution of skin lesions with treatment of the underlying malignancy.

Question 74

What is the most likely underlying condition for a patient with erythema gyratum repens?

Answer 74

The most likely underlying condition is malignancy, such as lung, breast, esophagus, or stomach cancer.

Question 75

What is the expected outcome of skin lesions in a patient with erythema gyratum repens after treating lung cancer?

Answer 75

The skin lesions are expected to resolve with treatment of the underlying malignancy.

Question 76

What is the characteristic appearance of erythema gyratum repens lesions?

Answer 76

The lesions have a 'wood-grain' pattern formed by concentric rings.

Question 77

What is the time frame for lesion onset relative to malignancy in erythema gyratum repens?

Answer 77

Lesions can occur from 1 year before to 1 year after the diagnosis of malignancy.

Question 78

What is the primary goal of topical corticosteroid treatment in erythema gyratum repens?

Answer 78

The primary goal is symptomatic relief.

Question 79

What other potential causes should be considered for erythema gyratum repens in the absence of known malignancy?

Answer 79

Other potential causes include abrupt onset without a cause and medication use.

Question 80

What are the clinical features of Erythema Annulare Centrifugum (EAC)?

Answer 80

EAC presents as a pink plaque that expands centrifugally, characterized by an annular/polycyclic shape with central clearing and trailing scale.

Question 81

What is the epidemiology of Erythema Migrans?

Answer 81

Erythema Migrans has a bimodal distribution, affecting ages 5-19 years and 55-69 years, with 70%-80% of individuals infected with Lyme disease.

Question 82

What are the histological findings associated with Erythema Marginatum?

Answer 82

Histological findings include nonspecific patchy interstitial and perivascular infiltrate composed of neutrophils.

Question 83

What are the risk factors associated with Erythema Annulare Centrifugum?

Answer 83

Risk factors include infections, malignancies, medications, and pregnancy.

Question 84

What are the histological findings associated with Erythema Annulare Centrifugum?

Answer 84

Histological findings typically show dense perivascular infiltrate in a 'coat sleeve' pattern, indicating non-specific inflammation.