Predictive evaluation in animals of the contact allergenic potential of medically important substances I. Comparison of different methods of inducing and measuring cutaneous sensitization

Groups of guinea pigs were sensitized with a 0.1% solution of dinitrochlorobenzene (DNCB) by the Draize intracutaneous method, The course of the induction process, the influence of the vehicles used and the extent to which the reactions are amenable to assessment according to objective criteria were examined. The sensitivity of the standardized Draize test was then compared with that of various other sensitization techniques, including:
The intracutaneous test with adjuvant (optimization test)
The maximization test according to Magnusson & Kligman (1969)
The epidermal sensitization test
The epidermal sensitization lest wish prior irritation of the contact site (by croton oil or sodium lauryl sulphate).
Comparison of these methods revealed that either the additional application of adjuvant or prior irritation of the contact site augmented the degree of sensitization to DNCR just as greatly as the simultaneous use of adjuvant and prior irritation of the skin, (maximization test.). The improved sensitization methods, and in particular the standardised optimization test, may prove to be of particular value for the study of so-called weak allergens.     

P73The magnitude of contact allergy responses can be quantified with imaged perfusion

Objective:  The objective of this study was to determine whether the magnitude of the perfusion of the contact hypersensitivity response as measured by the laser Doppler perfusion imaging (LDPI) technique was associated with immunological parameters implicated in the pathogenesis of the disease.
Methods:  Urushiol was applied on one of the forearms of volunteers for 48 hours while the other forearm served as a control. Twenty‐four hours later, measurements of perfusion of the patch test sites were performed with the LDPI technique. To determine whether there was a correlation with immunological parameters associated with human contact hypersensitivity, suction blisters were produced at the test sites. Blister fluid was removed and examined for the cytokine interleukin‐8 (IL‐8).
Results:  There was an extremely close correlation between the magnitude of the contact hypersensitivity response as measured by the imaged perfusion and the level of IL‐8 in the blister fluid (r = 1.00). Compared to subjects with visually positive urushiol reactions, patients who failed to develop urushiol contact hypersensitivity despite repeated exposures to that substance had both greatly diminished perfusion and blister fluid IL‐8 levels.
Conclusion:  The results indicate that LDPI is a sensitive method of quantifying contact hypersensitivity reactions in humans and that the magnitude of the measurements with this technique correlates extremely well with cutaneous cytokine levels that have been implicated in the immunopathogenesis of contact hypersensitivity.     

A comparison of three guinea-pig sensitization procedures for the detection of 19 reported human contact sensitizers

A maximization test (after Magnusson & Kligman 1970), a single injection adjuvant test (SIAT) and a modified Draize test procedure for assessing contact sensitization potential in guinea-pigs have been compared for their ability to detect 19 known human contact sensitizers. The results show that the modified Draize procedure is a good screening test particularly for strong sensitizers. The maximization procedure is a very stringent test of sensitization potential, able to detect some marginal sensitizers. The sensitivity of the SIAT procedure is sufficiently similar to that of the maximization test to act as an alternative for routine testing, particularly in view of its practical advantages over the maximization procedure.     

Studies of new short-period method for delayed contact hypersensitivity assay in the guinea pig

A new method for delayed contact hypersensitivity assay of chemical compounds in guinea pigs, a short-period method (14 days) with a high detection sensitivity, has been developed. The new method was as follows; a combination of a Freund's complete adjuvant (FCA, undiluted) intradermal injection and a 24–h occusive patch on a guinea pig was performed 2x at an interval of 4 days and challenged by non-occlusive topical application II days after the first sensitization (with benzyl alcohol during test development). Acanthosis and spongiosis in the epidermis and mononuclear cell infiltration into the dermis were observed histopathologically at the skin reaction site. This newly developed method (adjuvant and 24–h occusive patch 2 test: AP2 test) could equally and/or better detect the allergenicities of 6 other chemical compounds (bromostyrol, citronellal, benzyl salicyfate. p -aminobenzoic acid ethyl ester, phenylenediamine and formaldehyde) as compared with the cumulative contact enhancement test (CCET) and the guinea pig maximization test (GPMT).     

Studies of new short-period method for delayed contact hypersensitivity assay in the guinea pig

The enhancement effect of cyclophosphamide on the delayed contact hypersensitivity reaction of chemical compounds was studied in Hartley albino guinea pigs. A series of assay procedures. combining the AP2 test (adjuvant and 24-h occlusive patch 2× test, as previously reported) with intraperitoneal cyclophosphamide administration, were examined. The newly developed method was as follows; cyclophosphamide 200 mg/kg intraperitoneal administration 3 days before the 1st sensitization of the AP2 test (cyclophosphamide. adjuvant and 24-h occlusive patch 2× test: CAP2 test). Comparing the CAP2 test with the AP2 test, the cumulative contact enhancement test (CCET) and the guinea pig maximization test (GPMT), the CAP2 test equally and/or better enabled the detection of allergenicities not only of strong allergens such as bromostyrol, citronellal, p -phenylendediamine and formaldehyde, but also of weak allergens such as benzyl salicylate and p -aminobenzoic acid ethyl ester. Acanthosis and spongiosis in the epidermis and mononuclear cell infiltration into the dennis at the skin reaction site were histopathologically observed. Cyclophosphamide effectively enhanced the delayed contact hypersensitivity reaction of weak allergens.     

Contact allergy to corticosteroids in patients using inhaled or intranasal corticosteroids for allergic rhinitis or asthma.

BACKGROUND: Patients using topically applied corticosteroids are at risk of developing allergic contact hypersensitivity. OBJECTIVE: To assess prevalence of allergic contact hypersensitivity reactions to inhaled or intranasal corticosteroids. METHODS: A prospective study of 30 adult patients using inhaled or intranasal corticosteroids for conditions such as allergic rhinitis was performed. We used epicutaneous patch testing to determine the prevalence of allergic contact hypersensitivity to corticosteroids and common additives (propylene glycol and benzalkonium chloride) in inhaled and nasal corticosteroid preparations in this population. RESULTS: Of 30 patients, 4 (13%) had positive patch test results. 3 (10%) were allergic reactions and 1 (3%) was an irritant reaction. Half of the reactions were to a corticosteroid (budesonide) and half were to a common preservative in nasal preparations (benzalkonium chloride). CONCLUSION: This study supports other clinical evidence that contact dermatitis/mucositis from inhaled or intranasal corticosteroid products can occur. The corticosteroids or added agents such as preservatives can be causative and may result in allergic or irritant reactions, which can be relevant to clinical symptoms.     

Occupational allergic contact dermatitis from azithromycin in pharmaceutical workers: a case series

Background: Reports on hypersensitivity reactions to azithromycin associated with therapy or occupational exposure have been rare. Objectives: A case series describing clinical characteristics, diagnostic pathways and risk factors in occupational allergic contact dermatitis (ACD) caused by azithromycin in pharmaceutical workers is presented. Patients/Methods: 7 out of 21 pharmaceutical workers exposed to powdered intermediate and final substances in azithromycin synthesis were referred with workplace-related skin and respiratory symptoms. They all underwent diagnostic procedure involving medical history and examination, patch testing with standard allergens and azithromycin, prick testing with inhalatory allergens and total immunoglobulin E measurement. Results: Airborne ACD caused by azithromycin was established in 4 examined workers with positive patch test to azithromycin. 2 workers additionally had positive patch test to intermediate substances. Occupation-related symptoms of urticaria, rhinoconjunctivitis, laryngitis and/or dyspnoea were described in additional 2 workers without clearly positive patch test to azithromycin. 2 atopic workers had a shorter asymptomatic period between the beginning of the exposure to azithromycin and occurrence of skin symptoms than non-atopics (2-3 months versus 1-3 years, respectively). Conclusions: Our results suggest that daily manipulation with powdered azithromycin and intermediates is a main route of sensitization. Besides contact sensitization, other possible workplace-related azithromycin hypersensitivity reactions are indicated.     

Copper – a rare sensitizer

To determine the incidence of patch test reactions to copper, 2% copper sulphate was included in our routine patch test series. The allergic potential of copper sulphate was evaluated by the guinea pig maximization test method (GPMT). 13 of the 1190 eczema patients showed reactions (1.1%), but they were considered non-relevant. 3 series of GPMT demonstrated that copper sulphate was a grade I allergen. A critical review of the literature disclosed that several reports on cases of allergic contact dermatitis to copper must be regarded as uncertain or non-relevant. 4 cases were considered relevant and another 20 cases probably relevant. It is suggested that a test reaction to copper sulphate should be verified by a serial dilution test (SDT). Furthermore, the sensitivity of patients to other metals should be stated, so that one can be aware that false positive reactions from metal impurities, especially nickel, in the copper salt used for testing may occur.     

A critical commentary and updating of the guinea pig maximization test

The guinea pig maximization test (GPMT) of Magnusson and Kligman was published in 1969. Since then, a vast body of practical experience with the test has been accumulated. New information requires that certain aspects of the procedure be reevaluated, especially with regard to the interpretation of challenge results. In particular, awareness of the phenomenon of hyperirritable skin (the 'angry back' phenomenon) suggests that presently used controls are not always adequate and may overstate allergenicity owing to false-positive reactions. The control group should be exposed to a chemical insult at induction which provokes an inflammatory reaction comparable to the test substance. We present strategies to distinguish irritant from allergic responses. Allergic reactions should persist on rechallenge weeks later, while nonspecific irritant reactions generally fade and are irreproducible in particular animals. Finally, when a chemical is identified as a contact sensitizer of risk is necessary to estimate the relevance of the test result to usage in the real world.     

Contact urticaria from Emla cream

We report the first case of immediate-type hypersensitivity caused by Emla cream. A 55-year-old woman, after using Emla cream, went on to develop urticaria. An open test was positive to Emla cream. Patch tests and prick tests were performed with Emla cream, the components of Emla cream (lidocaine, prilocaine and castor oil) and other local anaesthetics. The patch test with lidocaine and the prick test with Emla cream were both positive. An intradermal test and subcutaneous administration of 3 anaesthetics that had negative patch tests and prick tests were performed and well tolerated, allowing their use. In the literature, anaphylactic reactions to lidocaine injections, delayed-type hypersensitivity after lidocaine subcutaneous injections and contact dermatitis from Emla cream have all been described. This first case of contact urticaria from Emla cream was due to lidocaine and did not show any cross-reaction with other local anaesthetics.     

Contact sensitivity to Pityrosporum ovale in patients with atopic dermatitis

Contact sensitivity and immediate hypersensitivity to extracts from Pityrosporum ovale were studied in patients with atopic dermatitis (AD). In a chamber-scarification patch test, 75 (64%) of 118 patients with AD responded positively, compared with 1 (3%) of 35 healthy volunteers. However, no significant statistical correlations were found between contact sensitivity to P ovale in patients with AD and any of the following factors: age, sex, distribution of skin lesions, presence of pruriginous papules, history of infantile seborrheic dermatitis, or concomitance of other atopic diseases. Lymphocyte transformation test with P ovale antigen confirmed that those with positive patch test reactions showed significantly high stimulation indexes. The antigenic substances divided by gel filtration high-performance liquid chromatography were found in a fraction of components with molecular weights above 60 kd. In addition, 25 (71%) of 35 patients with AD showed a positive immediate response to P ovale extract in a prick test, whereas none of 11 healthy volunteers showed any response. Although the incidence of the positive immediate responses was similar to that in contact sensitivity, there was no clear correlation between the delayed and immediate hypersensitivity reactions. Based on these results, we think that P ovale plays a role as an allergen derived from the host environment in the exacerbation of the skin lesions of AD.     

Oral cyclosporin inhibits the expression of contact hypersensitivity in man

The expression of delayed contact hypersensitivity was studied in 6 patients with chronic contact dermatitis treated with cyclosporin A (CsA) 5 mg/Kg/day. Quantitative patch test challenge was used to establish individual dose-response curves and threshold concentration to certain allergens in the European Standard Battery. In all 6 patients, responses were reduced over the whole range of allergen concentrations, and in the 5 in whom the threshold for expression of contact hypersensitivity could be determined, the threshold was raised by CsA therapy. In addition, the clinical manifestations of allergic contact dermatitis underwent complete resolution within 2-3 weeks of CsA therapy. It was concluded that CsA inhibits expression of delayed contact hypersensitivity reactions in human skin.     

Inhibition of cutaneous contact hypersensitivity in the mouse with systemic or topical spiperone: topical application of spiperone produces local immunosuppression without inducing systemic neuroleptic effects.

We tested the ability of the neuroleptic agent spiperone (8-[3-(p-fluorobenzoyl)propyl]-1-phenyl-1,3,8-triazaspiro-[4.5] decan-4- one) to influence the tissue swelling and leukocyte infiltration associated with T-cell--dependent immune responses, i.e., contact hypersensitivity reactions, in mice. Contact hypersensitivity reactions were elicited by applying the haptens oxazolone or dinitrofluorobenzene topically to one or both ears 5-8 d after epicutaneous sensitization. When spiperone was given subcutaneously at a dose of 30 or 150 mg/kg, 1 h after challenge with oxazolone, cutaneous contact hypersensitivity to this hapten was significantly diminished. When applied topically in concentrations as low as 0.08% (w/w), preparations of spiperone significantly suppressed both the tissue swelling and the leukocyte infiltration associated with the elicitation phase of contact hypersensitivity. Topical treatment with spiperone also suppressed the sensitization phase of contact sensitivity. However, mice treated topically with spiperone, unlike those treated systemically, exhibited no drowsiness or other evidence of central nervous system effects. Spiperone expresses both serotonin and dopamine receptor antagonist activity. However, unlike spiperone, the chemically unrelated serotonin antagonists, trazadone and mianserin, and the dopamine receptor antagonist, haloperidol, were not effective in suppressing contact hypersensitivity. Our results indicate that spiperone can have immunosuppressive effects on contact hypersensitivity reactions in the mouse, even when applied topically in doses that lack neuroleptic effects, and that the mechanism of action of spiperone on the immune response may be independent of its serotonin or dopamine receptor blocking properties.     

Contact and photocontact allergy in persistent light reactivity

The patient group consisted of 18 elderly male patients with persistent light reactivity who were subjected to extensive phototesting with different wavelengths, including patch and photopatch testing. All reacted adversely to ultraviolet light and some also to longer wavelengths when tested on normal appearing skin. 17 patients showed contact or photocontact reactions, of which 12 were positive photopatch test reactions and 11 were plain contact reactions. Contact allergy to constituents of oak moss and different lichen compounds was twice as common as allergy to Compositae oleoresins. 72 patients with chronic polymorphic light eruption were used as a control group. 10 of these patients had either a positive photopatch test reaction or a plain contact allergy. Patients with persistent light reactivity are characterized by a particular susceptibility to develop a delayed-type hypersensitivity. They frequently have both photo and plain contact allergy, often to substances used in cosmetics. In 13 of the 16 patients in whom a biopsy was carried out, the histology supported the clinical diagnosis. In none of the biopsies was the picture diagnostic in itself. This underlines the inadequacy of light microscopy as the only diagnostic procedure.     

Chlorhexidine anaphylaxis: case report and review of the literature

Chlorhexidine is a widely used antiseptic and disinfectant. Compared to its ubiquitous use in medical and non-medical environments, the sensitization rate seems to be low. Multivarious hypersensitivity reactions to the agent have been reported, including delayed hypersensitivity reactions such as contact dermatitis, fixed drug eruptions and photosensitivity reactions. An increasing number of immediate-type allergies such as contact urticaria, occupational asthma and anaphylactic shock have been reported. In the case report, we describe anaphylaxis due to topical skin application of chlorhexidine, confirmed by skin testing and sulfidoleukotriene stimulation test (CAST(R): cellular antigen stimulation test). The potential risk of anaphylactic reactions due to the application of chlorhexidine is well known, especially that application to mucous membranes can cause anaphylactic reactions and was therefore discouraged. The use of chlorhexidine at a 0.05% concentration on wounds and intact skin was so far thought to be safe. Besides our patient, only one other case of severe anaphylactic reaction due to application of chlorhexidine on skin has been reported. Hypersensitivity to chlorhexidine is rare, but its potential to cause anaphylactic shock is probably underestimated. This review should remind all clinicians of an important potential risk of this widely used antiseptic.     

Guinea pig maximization test open epicutaneous test and chamber test in induction of delayed contact hypersensitivity

A comparison was made between the guinea pig maximization test (GPMT), open epicutaneous rest (OET) and chamber test (CT), and the allergens were neomycin sulphate and propylene glycol (PG). The sensitization rate for neomycin in petrolatum was 35 % in GPMT, 25 % in OET and 25 % in CT. The corresponding figures for neomycin in PG were 30 % in GPMT, 45 % in OET and 32 % in CT. PG caused no hypersensitivity in 118 guinea pigs. The results suggested that as a hygroscopic, irritant and penetrating vehicle, PG facilitates the induction of delayed contact allergy, especially in OET.     

Contact hypersensitivity to hydrocortisone-free-alcohol in patients with allergic patch test reactions to tixocortol pivalate

It has been suggested that contact allergy to hydrocortisone alcohol is a frequent phenomenon, A recent study showed that all patients with allergic patch reactions to tixocortol pivalate reacted to intradermal hydrocortisone sodium phosphate. We studied patients with positive patch test reactions to tixocortol pivalate but negative to hydrocortisone alcohol, with penetration enhancers in hydrocortisone alcohol patch tests and oral challenges with hydrocortisone alcohol. Additionally, prick and intradermal tests with hydrocortisone sodium succinate were used. Using penetration enhancers and oral challenges enabled detection of more contact allergies to hydrocortisone alcohol compared to conventional patch testing alone. 9/12 patients with allergic reactions to tixocortol pivalate reacted to intradermal hydrocortisone sodium succinate. No immediate reactions were seen in prick or intradermal tests, suggesting that hydrocortisone contact hypersensitivity is probably not associated with immediate allergy to hydrocortisone. The present study suggests that allergic patch test reactions to tixocortol pivalate are caused by hypersensitivity to hydrocortisone alcohol itself or to one of its metabolites in the skin.     

Copper hypersensitivity: dermatologic aspects

Reports of immune reactions of both the immediate and delayed types due to cutaneous or systemic exposure to copper have been reviewed, in the endeavor to draw a comprehensive profile of the immunogenic potential of that metal and its compounds. The metal's immunotoxic potential is also briefly reviewed. In principle, as noted for other transition metals, the electropositive copper ion is potentially immunogenic due to its ability to diffuse through biological membranes to form complexes in contact with tissue protein. Based on predictive guinea pig test and the local lymph node assay (LLNA), copper has a low sensitization potential. Reports of immune reactions to copper include immunologic contact urticaria (ICU), allergic contact dermatitis (ACD), systemic allergic reactions (SAR) and contact stomatitis (STO), but considering the widespread use of copper IUDs and the importance of copper in coinage, items of personal adornment and industry, unambiguous reports of sensitization to the metal are extremely rare, and even fewer are the cases, which appear clinically relevant. Reports of immune reactions to copper mainly describe systemic exposure from intrauterine devices and prosthetic materials in dentistry, implicitly excluding induction of the hypersensitivity from contact with the skin as a risk factor. We provide a diagnostic algorithm that might clarify the frequency of copper hypersensitivity.     

Allergic Urticaria: A Case Report of Rare Skin Allergy with a Common Mouthwash

Chlorhexidine is a widely used antiseptic and disinfectant in medical and non-medical environments. Compared to its ubiquitous use, allergic contact dermatitis from chlorhexidine has rarely been reported and so its sensitization rate seems to be low. Chlorhexidine has been used for more than 50 years but it was only in the last two decades, that reports of immediate- type reactions to chlorhexidine were seen. Reactions ranging from localized urticaria to anaphylactic shock and hypersensitivity reactions, including delayed hypersensitivity reactions such as contact dermatitis, fixed drug eruptions, and photosensitivity reactions, began to appear more frequently. However the prevalence of contact urticaria and anaphylaxis due to chlorhexidine remains to be unknown. In this case report we have reported a case of urticaria due to oral use of chlorhexidine. The adverse reaction was confirmed by a skin prick test.     

Copper hypersensitivity

The world production of copper is steadily increasing. Although humans are widely exposed to copper‐containing items on the skin and mucosa, allergic reactions to copper are only infrequently reported. To review the chemistry, biology and accessible data to clarify the implications of copper hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common. As a metal, it possesses many of the same qualities as nickel, which is a known strong sensitizer. Cumulative data on subjects with presumed related symptoms and/or suspected exposure showed that a weighted average of 3.8% had a positive patch test reaction to copper. We conclude that copper is a very weak sensitizer as compared with other metal compounds. However, in a few and selected cases, copper can result in clinically relevant allergic reactions.