MDS Subspecialty: Medical Dermatology and Systemic Disease
Skin as a window
MDS questions test the skin manifestations of internal disease and complex medical dermatology. Know paraneoplastic syndromes (acanthosis nigricans, dermatomyositis, Sweet syndrome), connective tissue diseases (lupus, dermatomyositis, scleroderma), and vasculitis patterns (leukocytoclastic, IgA vasculitis, ANCA-associated).
Severe reactions and complex disease
Drug hypersensitivity syndromes (DRESS, SJS/TEN, AGEP) require recognition of timeline, mucosal involvement, and systemic features. Pyoderma gangrenosum, hidradenitis suppurativa, and severe psoriasis demand systemic management. Understand the role of multidisciplinary care and when to escalate.
Connective tissue disease clues
Heliotrope rash and Gottron papules suggest dermatomyositis with malignancy screening. Malar rash with photosensitivity suggests lupus. Raynaud phenomenon with sclerodactyly suggests systemic sclerosis. Each clue maps to a workup.
Traps
Questions often confuse cellulitis with pyoderma gangrenosum (biopsy and clinical context), or misattribute a drug eruption timeline. Another trap is failing to recognize that dermatomyositis in adults warrants age-appropriate malignancy screening.
Rule of thumb
When skin findings are accompanied by systemic symptoms (fever, weight loss, myalgia, mucosal involvement), broaden the differential beyond primary skin disease and consider paraneoplastic or autoimmune etiologies.
Worked example
A patient with violaceous periorbital rash, Gottron papules, and proximal weakness: dermatomyositis. The next step includes myositis antibody testing and malignancy screening, not simply topical steroids.