Patch testing for nickel allergy The influence of the vehicle on the response rate to topical nickel sulphate

A group of 43 patients with a clinical history of nickel allergy who exhibited an equivocal or no allergic reaction to a patch test at 48 h were further challenged using several different formulations of nickel sulphate. This experimental test battery comprised aqueous, dimethyl sulphoxide (DMSO) and propylene glycol (PG) solutions of nickel sulphate, and nickel sulphate incorporated into cetomacrogol cream and yellow soft paraffin (PMF). Although some of these vehicles were irritant, a formulation-dependent test response was observed, such that in terms of the number of responses per unit weight of nickel sulphate applied to the skin, the vehicles could be ranked: DMSO greater than PG greater than aqueous solution greater than cetomacrogol cream greater than PMF preparations. This ranking could be correlated with the relative ease with which nickel sulphate could be dialysed from each vehicle in vitro. This study demonstrates that for nickel sulphate, the vehicle can influence the outcome of patch testing apparently by modifying the quantity of nickel released into the skin for elicitation of the allergic response.     

Open, closed and intradermal testing in nickel allergy

Open, closed and intradermal testing with NiCl₂ was performed in 15 subjects with patch-test-proven allergy to 5% NiSO₄ in pet. Intradermal testing proved to be a reliable method in confirming nickel sensitivity within 24 h. Open testing with non-toxic concentrations of NiCl₂ in alcohol resulted in 73% and 93% positive reactions at 24 h and 48 h readings, respectively. This test method can be used as a reliable screening method in nickel allergy. Open testing often resulted in positive reactions within a few hours. This makes it possible to investigate pathogenetic events of acquired allergic contact dermatitis at a much earlier stage than with the usual 48-h occlusion. 24-h occlusion with Finn Chambers is not sufficient if one is to avoid false negative reactions in nickel allergy. Occlusion with Finn Chambers seems to delay the reaction.     

Attempts to induce contact allergy to nickel in the mouse

Various attempts to sensitize mice to nickel salts are described. The antigen was applied once or repeatedly by the epicutaneous or intracutaneous route and by combinations of the two. The procedures included prior irritation of the skin, treatment with Freund's complete adjuvant, cyclophosphamide or Tetramisol, and prior sensitization to picryl chloride. Contact allergy was achieved only by repeated epicutaneous application of a strong nickel solution over a 3-week period. The resulting dermatitis was demonstrated by a weak but significant wet weight increase of inflamed skin.     

Intradermal testing in doubtful cases of contact allergy to metals

Among 1670 consecutively patch tested patients an intradermal test with chromium, cobalt and nickel was added in 66 cases. There were three indications for intradermal testing: 1) the patch test reaction at 72 h was difficult to interpret; among 49 patients with one or more doubtful reactions a metal allergy was confirmed in 24 and rejected in 54. 2) ten patients with a negative patch test in spite of a positive history of metal allergy; among these, one was positive to cobalt, two to nickel and the other seven negative. 3) seven patients checked for a previously diagnosed allergy; a metal allergy was confirmed in four. Intradermal testing is recommended for confirmation of doubtful patch test reactions, particularly to disclose false positive reactions to metals.     

Is nickel allergy an occupational disease? Discussion of the occupational relevance of a type IV allergy to nickel (II) sulfate using case reports

Type IV sensitization to nickel (II) sulfate is common in the general population. Nickel can be found in different metals leading to occupational exposition in industrial professions.The individual clinical relevance of nickel allergy can easily be identified but it can be difficult to assess if nickel allergy was acquired privately or occupationally. The problem if nickel allergy fulfills the criteria of an occupational skin disease is presented in three case reports. The occupational relevance of a type IV sensitization to nickel in a chemical laboratory assistant, a flight attendant and a cashier are discussed. Important conditions for acquiring nickel allergy are contact with nickel‐plated and nickel‐releasing materials, the kind of skin contact, the status of the epidermal barrier, and the individual working conditions with an increased bioavailability of nickel. In cases of type IV sensitization to nickel, the affected person cannot continue to work in metal plating or with contact to nickel‐plated metals.The causal relationship between the type IV sensitization to nickel and the occupation needs to be clarified in each individual case. In general, occupationally caused nickel allergy is rare and the occupational relevance of nickel allergy is often overestimated.     

Beneficial effects of a skin tolerance-tested moisturizing cream on the barrier function in experimentally-elicited irritant and allergic contact dermatitis

In experimentally-induced irritant (ICD) and allergic (ACD) contact dermatitis, an oil-in-water (o/w) cream was applied to investigate its effects on a disturbed barrier function compared to untreated physiological barrier repair. Transepidermal water loss (TEWL) measurements were performed. Before the start of the experiments, the skin tolerance of the cream was examined, revealing the non-irritating characteristics of the ingredients and the absence of any contact allergic patch test reaction. In the ICD study, sodium lauryl sulfate (SLS) patches were applied to the forearms of young female volunteers. Consequently, it was observed that repeated cream application (14 days, 2x/day) significantly improved the TEWL of SLS-damaged skin, leading to a complete recovery on day 15. In the ACD study, disruption of skin barrier function was obtained by a nickel-mediated contact allergy patch (CAP) test. The cream was then applied 2x/day for 4 consecutive days. Assessment of TEWL clearly showed that recovery of the disrupted skin significantly improved after cream application in comparison to untreated barrier repair.     

Can pre-employment patch testing help to prevent occupational contact allergy?

175 subjects (157 female. 18 male) were patch tested with a standard series of allergens (Epipharm Allergy Service, GmbH, Linz, Austria), during pre-employment Examinations in the pharmaceutical industry, considered an industry at risk for the development of contact sensitization. None of those examined had contact dermatitis prior to testing and none gave a positive history of hand ecczema. Patch testing was positive in 12 (7%) subjects, of whom 7 showed a positive reaction to only 1 contact allergen and 5 reacted to several contact allergens. 5 subjects (2.9% reacted positively to metal salts (nickel, cobalt, chromium), 5 (2.9%) had a positive skin reaction to mixtures of rubber additives, and the remaining 2 to other allergens.     

Prevalence of nickel allergy among Finnish university students in 1995

Nickel allergy was studied in a sample of 1st-year university students starting their studies in 1995. A total of 296 subjects (72%) of 413 invited participated in the clinical examination, and 284, 96 male and 188 female, were patch tested (69%). A history of nickel sensitization was enquired for. Prick tests and serum specific IgE levels were determined. Occurrence of atopic dermatitis, hand eczema, and current exposure to metals were recorded. Nickel allergy was encountered in 39% of all female students, in 42% of females with pierced skin, and in 14% of females without pierced skin. The corresponding figures for males were 3%, 7% and 3%. In the multiple regression analysis, the risk factors for nickel allergy were female sex (OR 8.1, p<0.01), current metal exposure at examination (OR 4.1, p<0.01) and skin piercing (OR 3.6, p<0.05). Positive prick tests or elevated IgE levels to common allergens were not significantly associated with nickel allergy. In female students, the prevalence of nickel allergy has increased from 13% in 1986 to 39%. The prevalence among males has remained low at 3%. The results indicate that, in addition to skin piercing, current metal contacts are important risk factors for nickel allergy. This finding gives support to the EU Nickel Directive.     

Atopy in subjects with a history of nickel allergy but negative patch tests

Various markers of atopy were studied in 20 subjects with a history of nickel allergy but negative patch test reactions, and compared with 2 control groups: 13 subjects with no history of nickel allergy and negative patch tests; 11 subjects with a history of nickel allergy and positive patch tests. No significant difference in the incidence of atopy was detected in the 3 groups.     

Dose per unit area - a study of elicitation of nickel allergy

BACKGROUND: Experimental sensitization depends upon the amount of allergen per unit skin area and is largely independent of the area size. OBJECTIVES: This study aimed at testing if this also applies for elicitation of nickel allergy. PATIENTS/METHODS: 20 nickel allergic individuals were tested with a patch test and a repeated open application test (ROAT). Nickel was applied on small and large areas. The varying parameters were area, total dose and dose per unit area. RESULTS: In the patch test, at a low concentration [15 microg nickel (microg Ni)/cm(2)], there were significantly higher scores on the large area with the same dose per area as the small area. At higher concentrations of nickel, no significant differences were found. In the ROAT at low concentration (6.64 microg Ni/cm(2)), it was found that the latency period until a reaction appeared was significantly shorter on the large area compared to the small area. It was also found that the ROAT threshold (per application) was lower than the patch test threshold. CONCLUSION: For elicitation of nickel allergy, the size of the exposed area and therefore the total amount of applied nickel, influence the elicitation reaction at some concentrations, even though the same dose per unit area is applied.     

Diagnostic value of the lymphocyte proliferation test in nickel contact allergy and provocation in occupational coin dermatitis

The lymphocyte proliferation test (LPT) was compared with the patch test in the diagnosis of nickel contact sensitivity. Of the 21 subjects with nickel contact allergy, the patch test detected 20 (95%). The subject remaining negative in the patch test was positive in the intradermal test. 18/21 subjects with nickel contact sensitivity were positive in the LPT, whereas in the control group 2/23 subjects were false positive. These results were obtained at nickel sulfate concentrations of less than 10 micrograms/ml, higher concentrations led to nonspecific lymphocyte stimulation. 3 nickel-sensitive cashiers with suspected coin contact-induced deterioration of their hand eczema were challenged by having them count nickel-containing coins daily for 15 min. 2 of them developed vesicular eczema on their palms and fingers in 2 to 3 days. The present results show that the LPT is a reliable additional test in the diagnosis of nickel contact sensitivity. Furthermore, provocation is a valuable procedure when assessing the relevance of nickel contact in occupational hand eczema in certain occupations.     

Allergy to nickel or cobalt: tolerance to nickel and cobalt samples in man and in the guinea pig allergic or sensitized to these metals

The aim of this study was to evaluate, in animals and humans sensitive to nickel or cobalt, the tolerance to manufactured metal samples of nickel and cobalt of a defined metallographic structure, plated or not with a layer of chrome or copper/chrome of a determined thickness. Under the defined experimental conditions, a guinea pig sensitized to one metal (nickel or cobalt) was intolerant to both metals (nickel and cobalt). A plating of chrome or copper/chrome did not act as a protection. In the human, it was not the same: the tolerance to metal samples was determined by the specific sensitivity. A plating of chrome or copper/chrome did not act as protection.     

Relationship between nickel and cobalt sensitization in hard metal workers

853 hard metal workers were examined and patch tested with 20 substances from their environment, including nickel and cobalt. Nickel sensitivity was found in 2 men and 38 women. 88% of the nickel-sensitive individuals had developed a jewelry dermatitis prior to employment in the hard metal industry or before the appearance of hand eczema. 29% of the hard metal workers gave a history of slight irritant dermatitis. In the nickel sensitized group, 40% had had severe hand eczema which generally appeared 6-12 months after starting employment. In 25% of the cases, nickel sensitive individuals developed cobalt allergy, compared with 5% in the total population investigated. Most facts indicate that nickel sensitivity and irritant hand eczema precede cobalt sensitization. Hard metal workers with simultaneous nickel and cobalt sensitivity had a more severe hand eczema than those with isolated cobalt or nickel sensitivity or only irritant dermatitis. 64% of the female population had pierced ear lobes. Among the nickel allergic women, 95% had pierced ear lobes. The use of earrings containing nickel after piercing is strongly suspected of being the major cause of nickel sensitivity. Piercing at an early age seems to increase the risk of incurring nickel sensitivity.     

Trend of contact allergy to cosmetic ingredients in Thais over a period of 10 years

Background. Contact allergy to cosmetic ingredients is common. However, there are no recent comprehensive studies on contact allergy to cosmetic ingredients in Asia. Objectives. To identify positive patch test reactions in patients tested at Siriraj Hospital, Bangkok, Thailand to allergens present in cosmetics. Methods. A retrospective review of medical records from the outpatient contact dermatitis clinic was conducted from January 1999 to December 2008. Patients with at least one positive patch test reaction to allergens associated with cosmetic ingredients were studied. The results were evaluated using Pearson's χ²‐test with Yates' continuity correction or Fisher's exact test where appropriate,and a p‐value <0.002 was considered to be statistically significant by Bonferroni correction. Results. There were 1247 cases (239 males and 1008 females; mean age 38.5 years). Fragrance chemicals and preservatives were the most commonly recognized cosmetic allergens. Ammoniated mercury was the only allergen that showed a significantly increased frequency over the 10‐year period (p = 0.0008). Conclusions. Our study showed that ammoniated mercury is an emerging cosmetic allergen, showing an increased prevalence in recent years in Thailand. A focus is required on emerging cosmetic allergens and what may account for the upward trend of cosmetic contact dermatitis.     

In vivo testing of the protection of gloves against acrylates in dentin-bondingsystems on patients with known contact allergy to acrylates

Occupational contact allergies to dental acrylates are increasing. Commonly used gloves protect poorly against acrylates. The protective efficacy in vivo of other, newer glove materials is not fully known. In this study, an open chamber system was used for testing the protection in vivo of 6 different gloves (1 vinyl glove, 2 latex gloves, 2 nitrile gloves and the 4H glove) against a commonly used dental adhesive, Scotchbond 1, containing 2-hydroxyethyl methacrylate (2-HEMA) and triethylene glycol dimethacrylate (TREGDMA). 8 patients with known contact allergy to 2-HEMA participated. Provocation with 50 microl of the adhesive for 7.5, 15 and 30 min was performed for each glove. The test demonstrated clear differences in the protective efficacy between the gloves. The 4H glove gave by far the best protection, followed by one of the nitrile gloves. One of the latex gloves and the vinyl glove gave a very poor protection against the adhesive. A dose-response relationship was observed between different application times of the acrylate product. The test model promises to be a useful clinical complement to in vitro methods in individual preventive measures against contact sensitization to acrylates.