20 - Figurate erythemas

Question 1

what are the four classical figurate ertyehmas?

Answer 1

• erythema annulare centrifugum
• erythema marginatum
• erythema migrans
• erythema gyratum repens

Question 2

what are the associations / causes of erythema annulare centrifigum?

Answer 2

• infectious aeitology - e.g dermatophy, viruses, parasites and ectoparasites.
• drugs like diuretics, non steroidal anti-inflammatory drugs including antimalarials and gold.

Question 3

what are the histopathological features of erythema annulare centrifugum?

Answer 3

• mild spongiosis
• focal parakeratosis
  ‘coat-sleeve’ sign - inflammatory cells in a tight aggregate around vessels.

Question 4

what are the clinical features of erythema marginatum?

Answer 4

• erythematous macules that spread peripherally.

- usually located on the trunk, axilla, proximal extremities.