Identify the condition?
Ans. A. Erythema multiforme
- Given picture is showing multiple target lesions i.e. concentric rings of different shades of erythema which is characteristic of erythema multiforme.
- Palms and soles are common sites.
- Typically in erythema multiforme, few to hundreds of skin lesions erupt within 24 hours. The lesions are first seen on the backs of hands and/or tops of feet and then spread down the limbs towards the trunk. The upper limbs are more commonly affected than the lower. Palms and soles may be involved. The face, neck and trunk are common sites. Skin lesions are often grouped on elbows and knees. There may be an associated mild itch or burning sensation.
- The initial lesions are sharply demarcated, round, red/pink and flat (macules), which become raised (papules/palpable) and gradually enlarge to form plaques (flat raised patches) up to several centimeters in diameter. The center of the papule/plaque darkens in color and develops surface (epidermal) changes such as blistering or crusting. Lesions usually evolve over 72 hours.
- The typical target lesion (also called iris lesion) of erythema multiforme has a sharp margin, regular round shape, and three concentric color zones:
- The center is dusky or dark red with a blister or crust
- Next ring is a paler pink and is raised due to edema (fluid swelling)
- The outermost ring is bright red.
- Atypical target lesions show just two zones and/or an indistinct border.
- The eruption is polymorphous (many forms), hence the ‘multiforme’ in the name. Lesions may be at various stages of development with both typical and atypical targets present at the same time. A full skin examination may be required to find typical targets, as these may be few.
- Lesions show the Köbner (isomorphic) phenomenon, meaning they can develop at sites of preceding (but not concurrent or subsequent) skin trauma.
- There is no associated swelling of face, hands or feet, despite these being common sites of rash distribution. However, the lips are often swollen, especially in erythema multiforme major.