Like case 1, case 2 did not present with visual features of bullous pemphigoid, Henoch-Schönlein purpura, IgM/IgG immune complex vasculitis, tumid lupus erythematosus, Well’s syndrome, erythema multiforme, or cutaneous mastocytosis, and lacked fever-associated with cryopyrin-associated periodic syndrome. Here, CD40LG is linked to cutaneous mastocytosis.