A marked eosinophilic infiltrate is present. Capillary proliferation manifests as masses of canalized swollen endothelial cells. Fibrosis usually surrounds and may extend into lesions. In contrast, lesions of ALHE are more superficial, with lymphoid follicles lacking germinal centers. Masses of uncanalized endothelial cells demonstrate cytologic atypia, often termed histiocytoid in appearance.
Observation is acceptable if the lesions are neither symptomatic nor disfiguring.
Intralesional or oral steroids can shrink the nodules but seldom result in cure. A medium-potency steroid, such as triamcinolone, used in solution form for intralesional injection usually is well tolerated. Cyclosporine recently was reported to induce remission in a patient with KD of the earlobe. Radiotherapy has been used to treat recurrent or persistent lesions. Considering the benign nature of KD, radiation should be reserved as a second-line treatment.