Skin Prick Test with Self-Saliva in Patients with Oral Aphthoses: A New Diagnostic Pathergy for Behcets Disease and Recurrent Aphthosis

Abstract

There may be some difficulties to differentiate Behcet’s disease (BD), recurrent aphthosis (RA), and herpetic aphthous ulceration, from other mimicking oral disorders. Despite of unexpected sensitivity and responsiveness, the skin pathergy test regarding a non-specific hypersensitivity has long been thought as one of auxiliary diagnostic benefits for BD.To determine the potential usefulness and disease specificity of the prick reaction with saliva, a skin prick test with neat and filter-sterilized saliva was performed on the forearm skin of 26 individuals; 10 patients with BD (8 incomplete type without uveitis, 1 complete type, and 1 neurological type), 5 with RA, 3 with herpetic oral aphthosis, 2 with erythema nodosum alone, and 6 healthy controls. We assessed the skin reaction at 48 hours after pricking, and the pricked skin lesions were biopsied and analyzed immunohistologically.Nine of 10 BD patients (90 %) exhibited an indurative erythema at the skin site pricked with self-saliva, whereas 3 of 5 RA patients (60%) were relatively weak reaction. Pricking with filter-sterilized saliva failed to recapitulate any of positive skin reactions, albeit a faint erythematous dot appeared in a few BD patients, implicating the involvement of causative microorganism(s) in oral bacterial flora. Culture of saliva from 3 randomly chosen BD patients revealed numerous streptococcal colonies on Mitis-Salivarius agar. Histology of the pricked skin sites showed perivasucular inflammatory infiltrates, composed of CD4+ T cells and CD68+ monocyte/macrophage lineage, a feature consistent with a delayed type hypersensitive reaction.Our results suggested that skin prick test using self-saliva (a new diagnostic pathergy) can be a simple and valuable in vivo diagnostic approach for differentiating BD and RA from other mimicking mucocutaneous diseases. The positive skin prick may be triggered by resident intra-oral microflora, particularly streptococci, and may in part address the underlying immunopathology in BD.

Behçet's disease: A comprehensive review with a focus on epidemiology, etiology and clinical features, and management of mucocutaneous lesions

“…The more important reason seems to be the widespread use of disposable needles instead of blunt, reusable, sterilized needles. Recently Togashi et al 19 have proposed a new diagnostic pathergy test to overcome this problem. They performed a skin prick test with neat and filter-sterilized saliva on the forearm skin.…”

Salivary changes in oral mucosal diseases

“…Interestingly, pricking with filter‐sterilized saliva failed to produce a positive skin reaction when neat saliva was used. Furthermore, microbial culture of saliva from patients with Behcet's disease revealed numerous streptococcal colonies ; these findings suggest that a skin‐prick test using self‐saliva can be a simple and valuable in vivo diagnostic approach for differentiating Behcet's disease from other oral diseases. These findings warrant further evaluation in large‐scale studies.…”

“…Pathergy is a reaction seen in some patients with Behcet's disease to a sterile needle prick . A skin‐prick test with the patient's own saliva has been recently described to be of diagnostic importance in patients with Behcet's disease: 90% of patients with Behcet's disease exhibited an indurated erythema at the skin site pricked with their own saliva . Interestingly, pricking with filter‐sterilized saliva failed to produce a positive skin reaction when neat saliva was used.…”

The Epidemiology of Behçet’s Disease

“…This information suggests that the positive reaction might be a cutaneous response to some bacteria living on the surface of the skin. In a recent study, performed by Togashi et al suggested that a new diagnostic pathergy test may solve the methodological problems [62]. They performed a skin prick test with ilter-sterilized saliva on forearm skin.…”

“…Of the patients with BD, 90% showed indurative erythema at the skin site pricked with self-saliva, and 60% of recurrent aphthous stomatitis patients showed weak reaction. They suggested that skin prick test using self-saliva can be a diagnostic test for differentiating BD from other mucocutaneous diseases [62].…”