Dermatomyositis is a connective tissue disorder characterized by chronic inflammation of voluntary muscles and skin. It is more common in women and the age of onset is 50-70 years.
A) Heliotrope Rash:
- It is a macular, confluent, purple or purple/red rash over both eyelids and periorbital tissue present with or without edema.
- Mechanism: Unclear; probably indicates inflammation of underlying striated orbicularis oculi rather than the overlying skin
- Resembles Heliotropium peruvianum flower, which has small purple petals.
B) Gottron’s Papules:
- Violaceous (violet-coloured) papules on the dorsal aspect of the interphalangeal joints.
- Mechanism: Unclear
- Pathognomic sign
C) Shawl sign:
- Confluent, violaceous, macular (i.e. flat with violet/purple colouring) rash over the posterior shoulders and neck.
- Mechanism: microvascular injury by complement deposition
D) Other skin signs:
- Nail fold telangiectasia
- Scaly scalp