The disease results from an abnormal proliferation of lymphoid follicles and vascular endothelium. The presence of eosinophils in the inflammatory infiltrate and in the peripheral blood suggests that KD represents a hypersensitivity reaction. Evidence exists that TH2 lymphocytes play a role, but further investigation is needed. KD is confined to the skin. An association with nephrotic syndrome has been reported, but the basis for this possible association is unclear.
Lesions can grow to be large and disfiguring.
KD is most common in Asians, while ALHE occurs in all races. A series by Kung et al reported a median age of 28 years. Patients with ALHE tend to be older persons. Lesions of KD typically are painless, with occasional pruritus of the overlying skin. Findings include solitary or multiple, firm, subcutaneous nodules, which usually are located on the head or neck.