Kimuras disease is a benign rare chronic inflammatory disorder. Its primary symptoms are subdermal lesions in the head or neck or painless unilateral inflammation of cervical lymph nodes. Cause
Its cause remains unknown. Reasons such as an allergic reaction, tetanus toxoid vaccination, or an alteration of immune regulation are suspected. Other theories like persistent antigenic stimulation following arthropod bites and parasitic or candidal infection have also been proposed. To date, none of these theories has been substantiated. Pathophysiology
The pathophysiology of Kimuras disease remains unknown, although an allergic reaction, trauma, and an autoimmune process have all been implicated as possible causes. The disease is manifested by an abnormal proliferation of lymphoid follicles and vascular endothelium. Peripheral eosinophilia and the presence of eosinophils in the inflammatory infiltrate suggest it may be a hypersensitivity reaction. Some evidence has indicated TH2 lymphocytes may also play a role, but further investigation is needed.Kimuras disease is generally limited to the skin, lymph nodes, and salivary glands, but patients with Kimuras disease and nephrotic syndrome have been reported. The basis of this possible association is unclear. Diagnosis
An open biopsy is the chief means by which this disease is diagnosed. "Lymphoid nodules with discrete germinal centers can occupy an area extending from the reticular dermis to the fascia and muscle. Follicular hyperplasia, marked eosinophilic infiltrate and eosinophilic abscesses, and the proliferation of postcapillary venules are characteristic histological findings. [18] Centrally, thick-walled vessels are present with hobnail endothelial cells. Immunohistochemical evaluation of the lymphoid nodules demonstrates a polymorphous infiltrate without clonality.
[12, 27] Reports have also demonstrated the presence of plasmacytoid dendritic cells in a lesion of Kimura disease. [40] Histopathological examination is an effective way to establish the diagnosis." Treatment
Observation is acceptable if the lesions are neither symptomatic nor disfiguring. Intralesional or oral steroids can shrink the nodules, but seldom result in cure. Cyclosporine has been reported to induce remission in patients with Kimuras disease, but recurrence of the lesions has been observed once this therapy is stopped.Cetirizine is an effective agent in treating its symptoms. Cetirizines properties of being effective both in the treatment of pruritus (itching) and as an anti-inflammatory agent make it suitable for the treatment of the pruritus associated with these lesions. In a 2005 study, the American College of Rheumatology conducted treatments initially using prednisone, followed by steroid dosages and azathioprine,  omeprazole, and calcium and vitamin D supplements over the course of two years. The skin condition of the patient began to improve and the skin lesions lessened. However, symptoms of cushingoid and hirsutism were observed before the patient was removed from the courses of steroids and placed on 10 mg/day of cetirizine to prevent skin lesions; an agent suitable for the treatment of pruritus associated with such lesions. Asymptomatically, the patients skin lesions disappeared after treatment with cetirizine, blood eosinophil counts became normal,  corticosteroid effects were resolved, and a remission began within a period of two months.