This study evaluates the effects of Nickel oral hyposensitization treatment (NiOHT) on health-related quality of life (HRQoL) of patients suffered from Systemic Nickel Allergy Syndrome (SNAS).

Nickel (Ni) is a nutritionally essential metal widely distributed in the environment, and it has been reported to be one of the most common causes of allergic contact dermatitis (ACD), affecting nearly 15-20% of the general population. As known, Ni-hypersensitivity can induce less frequently also respiratory allergy (RA) and in approximately 20% of Ni-ACD patients cause a more complex condition termed Systemic Nickel Allergy Syndrome (SNAS). It is characterized by a combination of cutaneous (in regions without direct nickel contact) and extracutaneous gastrointestinal symptoms, after the ingestion of Ni-rich foods, especially vegetables. Then, a low-Ni diet, following positive patch tests, represents a effective diagnostic and therapeutic tool in the control of systemic manifestations, determining a significant clinical improvement.

It is known that Nickel oral hyposensitization treatment (NiOHT) is a effective approach for the management of Ni allergy, especially in a subset of patients with SNAS, inducing immunological and clinical tolerance to metal at the doses normally taken with the diet.

Although a large number of clinical trials focused on the health-related quality of life (HRQoL) in allergic disease, the expectations, the needs and the psychosocial characteristics of patients affected by SNAS are limited and no data exist pre- and post-treatment and specifically with NiOHT. Given the high safety profile and beneficial effects of immunotherapy on HRQoL of patients with allergic rhinitis, we hypothesized similar positive results even after oral Ni desensitization.

Inclusion Criteria:

• history of SNAS (coexistence of typical cutaneous and gastrointestinal symptoms),
• positive Ni-patch test,
• clinical improvement at least 70% from baseline after 4 weeks on a low-Ni diet,
• positivity of a double blind placebo-controlled oral Ni challenge (DBPCO),
• written informed consent.

Exclusion Criteria:

• age < 18 years and > 65 years,
• other organic gastrointestinal diseases, such as peptic ulcer, inflammatory bowel diseases, celiac disease, gastrointestinal infections, and small intestinal bacterial overgrowth,
• diabetes mellitus,
• hepatic, renal or cardiac dysfunction,
• thyroid disease or tumor,
• concomitant treatment with steroids and/or antihistamines in the previous 4 weeks, pregnancy, lactation,
• smoking, abuse of alcohol, coffee, tea, and cola intake,
• refusal to participate.

The Researchers enrol patients suffer from Systemic Nickel Allergy Syndrome (SNAS), condition characterised by a combination of cutaneous (in regions without direct nickel contact) and extracutaneous gastrointestinal symptoms, after the ingestion of Nickel-rich foods, especially vegetables.