7 - 46 - ERYTHEMA ANNULARE CENTRIFUGUM AND OTHER FIGURATE ERYTHEMAS

Question 1

variants of EAC

Answer 1

*** superficial variant: **lesions are slightly elevated and demonstrate desquamation at the inner margin, also referred to as a “trailing scale”
* deep variant: has an indurated, firm border, often without prominent scaling

Question 2

most common symptom associated with EAC

Answer 2

pruritus

Question 3

most frequent sites of involvement of EAC

Answer 3

buttocks, thighs, and trunk

Question 4

characteristic scale of EAC

Answer 4

desquamation at the inner margin, also referred to as a “trailing scale”

Question 5

risk factors for EAC

Answer 5

infections, malignancies, medications, pregnancy, and other systemic diseases

• In one study, 40% of patients with EAC had a concomitant superficial dermatophyte infection, most commonly tinea pedis, and 13% had internal malignancies, including non-Hodgkin lymphoma and acute myelogenous leukemia

Question 6

this infection may be a risk factor for EAC.

Answer 6

Dermatophyte infections

• In cases associated with tinea pedis, lesions of EAC tend to resolve with treatment of the dermatophytosis
• In addition to dermatophytoses, EAC is associated with other cutaneous infections such as molluscum contagiosum and herpes zoster, as well as systemic infections, including Epstein-Barr virus and HIV.

Question 7

histopath finding of EAC

Answer 7

• dense perivascular infiltrate composed of lymphocytes, histiocytes, and occasional eosinophils that tightly wraps around blood vessels described as “coat-sleeve” pattern

Question 8

Cutaneous manifestation of early localized Lyme disease that occurs at the site of the bite of Ixodes species ticks

Answer 8

ERYTHEMA MIGRANS

Question 9

insect vector of Lyme disease

Answer 9

Ixodes scapularis tick

Question 10

bacteria causing Lyme disease

Answer 10

Borrelia burgdorferi

Question 11

annular erythema that expands to create a “bull’s-eye” appearance

Answer 11

ERYTHEMA MIGRANS

Question 12

3 stages of Lyme disease

Answer 12

**1. early localized disease: **characterized by erythema migrans
2. early disseminated disease: if untreated, patients can progress to the second stage of Lyme disease, which involves widespread spirochete dissemination with neurologic, rheumatologic, and cardiac involvement
3. chronic disease:persistent neuroborreliosis, severe erosive arthritis, and acrodermatitis chronica atrophicans

Question 13

hallmark cutaneous finding of the first stage of Lyme disease

Answer 13

Erythema migrans occurs at the initial site of the tick bite

• It is characterized by an erythematous expanding annular plaque with a central area of clearing, often described as a “bull’s-eye” lesion
• Lesions grow centrifugally and can grow at a rate of up to **3 cm per day. **
• At the time of presentation, the mean diameter of lesions of erythema migrans are 10 to 16 cm, depending on the site of involvement, with larger lesions found on the trunk and smaller lesions found on the lower extremities.
• Multiple lesions of erythema migrans can be seen in the setting of multiple tick bites or spirochetemia or lymphatic spread

Question 14

most common associated symptoms of erythema migrans

Answer 14

**warmth, pruritus, and pain, **although it can be asymptomatic

• In some cases, erythema migrans can be vesicular.

Question 15

Primary lesions of erythema migrans occur in areas where tick bites are likely to occur and go unnoticed, such as what areas?

Answer 15

trunk, axillae, groin, and popliteal fossae

Question 16

In most cases, ticks must be attached for at least how many hours before bacteria is transmitted?

Answer 16

24 hours

Question 17

erythema migrans occurs at the site of the bite approximately how many days after tick detachment?

Answer 17

7 to 14 days after tick detachment (range: 3 to 30 days)

• Approximately 70% to 80% of individuals infected with Lyme disease develop lesions of erythema migrans, and up to 45% of patients presenting with erythema migrans have spirochetemia

Question 18

Acrodermatitis chronica atrophicans is typical at what stage of Lyme disease

Answer 18

Chronic Lyme disease

Question 19

characterized by enlarging, edematous plaques on the distal extremities with a bluish-red hue that evolve into atrophic plaques

Answer 19

Acrodermatitis chronica atrophicans

Question 20

benign reactive lymphoid hyperplasia that can occur in response to untreated Borrelia infections

Answer 20

Borrelial lymphocytoma

Question 21

Borrelial lymphocytoma is usually observed in what stage of lyme disease?

Answer 21

early disseminated

more associated with Borrelia afzelii and Borrelia garinii

Question 22

most common antibiotics used to treat Lyme disease

Answer 22

doxycycline, amoxicillin, and cefuroxime

Question 23

Prophylaxis with a single dose of what antibiotic is indicated to decrease the risk of developing Lyme disease?

Answer 23

doxycycline

Question 24

doxycycline prophylaxis can be started within how many hours of tick removal?

Answer 24

72 hours

Prophylaxis with a single dose of doxycycline is indicated to decrease the risk of developing Lyme disease only when the individual is from an endemic area, has been bitten by a tick identified as I. scapularis, has had tick attachment for longer than 36 hours, and prophylaxis can be started within 72 hours of tick removal.

Question 25

doxycycline prophylaxis is indicated if the tick attachment is longer than how many hours?

Answer 25

36 hours ## Footnote Prophylaxis with a single dose of doxycycline is indicated to decrease the risk of developing Lyme disease only when the individual is from an endemic area, has been bitten by a tick identified as I. scapularis, has had tick attachment for longer than 36 hours, and prophylaxis can be started within 72 hours of tick removal.

Question 26

Cutaneous manifestation of **rheumatic fever**, occurring after pharyngeal infection with group A β-hemolytic streptococcus.

Answer 26

ERYTHEMA MARGINATUM ## Footnote * 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. * The borders of the lesions are often well demarcated. * There are usually no epidermal changes present and the lesions are often asymptomatic. * Individual lesions tend to **appear and disappear**, and** may be more evident with hot showers or baths.**

Question 27

diagnostic criteria of rheumatic fever

Answer 27

Major Criteria: 1. Carditis 2. Migratory polyarthritis 3. Sydenham chorea 4. Subcutaneous nodules 5. Erythema Marginatum Minor Criteria 1. fever 2. arthralgias 3. abnormal laboratory findings such as elevated ESR, CRP, or a prolonged PR interval on echocardiogram Required for diagnosis: 2 major or 1 major and 2 minor criteria (2-0-1-2)

Question 27

One of the major criteria of acute rheumatic fever.

Answer 27

ERYTHEMA MARGINATUM ## Footnote * Only seen in a minority of patients with acute rheumatic fever * seen in fewer than 10% of patients with acute rheumatic fever. * It occurs more often in **children** than in adults, with peak age of onset between 5 and 15 years

Question 28

Acute rheumatic fever occurs as a complication of what infection secondary to what bacteria?

Answer 28

antecedent pharyngeal infection with group A β-hemolytic streptococcus

Question 29

areas of predilection of erythema marginatum

Answer 29

**trunk, axillae, and proximal extremities,** and typically spare the face

Question 30

Individual lesions tend to **appear and disappear**, and** may be more evident with hot showers or baths.**

Answer 30

Erythema marginatum

Question 31

less-common complication associated with acute rheumatic fever which is a chronic, painless arthropathy of the hands and feet.

Answer 31

Jaccoud arthropathy

Question 32

Usually a paraneoplastic phenomenon

Answer 32

ERYTHEMA GYRATUM REPENS

Question 33

Characteristic wood grain appearance with multiple concentric rings.

Answer 33

ERYTHEMA GYRATUM REPENS ## Footnote * The epidermis often has a **superficial scale at the edges**, and patients often complain of **pruritus**. * The onset of the lesions can occur from **1 year before to 1 year after the diagnosis of malignancy**. * Additional associated cutaneous findings can be seen, which include **acquired ichthyosis and palmoplantar keratoderma**

Question 34

Thought to be an immune reaction caused by cross-reaction between tumor and skin antigens.

Answer 34

ERYTHEMA GYRATUM REPENS

Question 35

most common cancers associated with Erythema gyratum repens

Answer 35

lung, breast, esophagus, and stomach neoplasms

Question 36

Erythema gyratum repens features multiple, erythematous, annular lesions that advance at a rapid rate of up to how many cm per day?

Answer 36

1 cm

Question 37

erythema annular centrifugum (EAC)

Answer 37

Question 38

Erythema migrans

Answer 38

Question 39

Erythema marginatum (also, erythema marginatum rheumaticum)

Answer 39

Question 40

Erythema gyratum repens

Answer 40