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Finn Chambers (finn + chamber)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Assessment of balsam of Peru patch tests

CONTACT DERMATITIS, Issue 6 2000
Bolli Bjarnason
To find an ideal test technique for as low a dose of balsam of Peru (Myroxylon Pereirae) as possible, subjects testing positive to balsam of Peru are re-tested with a 25% concentration of balsam of Peru in petrolatum. Applications are with Finn Chambers® for 6 different application times, and directly by foils for 96 h (4 days (D)). The goals are to confirm which subjects are positive and which are not, and, using that information, to see if it is possible to distinguish between these 2 groups, tested concomitantly at much lower serial dose levels, in terms of perfusion or by visual assessments. 5 different serial doses are applied with strips for 3,96 h (4D) and with foils for 96 h (4D). The Finn Chamber® tests allow a distinction between visually positive and negative subjects supported by perfusion assessments. With the foils, a 24× lower serial dose level than with the 25% test substance is sufficient to distinguish between positive and negative subjects in terms of perfusion values. This approach requires readings up to 9 days. With this test, the visual approach yields only 3 of 10 positive subjects. This study demonstrates that a lower test dose is possible with perfusion assessments compared to visual ones. [source]

Artificial disruption of skin barrier prior to irritant patch testing does not improve test design

BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2004
K.L. Gebhard
Summary Background, Irritant patch testing is often performed as a 24- or 48-h occlusive patch test with low concentrations of sodium lauryl sulphate (SLS). Objectives, The aim of this study was to investigate potential ways to shorten this test procedure and obtain precise test results. Patients and methods, Thirty-six healthy volunteers underwent irritant patch testing with different pretreatments (PT) of the test fields. Occlusive test chambers were applied on the upper back with SLS 0·5%, 1%, 2% and 5% in large Finn Chambers®. The patches were removed after 4 and 24 h, respectively, depending on the concentration used. Test fields were pretreated as follows: PT 0, field without any PT (control); PT 1, prick with lancet; PT 2, prick with test stamp; PT 3, scratch with lancet; PT 4, incision with standardized incision instrument (0·1,0·2 mm depth). Skin reactions were evaluated by transepidermal water loss (TEWL), skin erythema and skin hydration and as well by a visual score (VS) at 4, 24 and 72 h. Results, Our data show an obvious distinction between PT 0,2 and PT 3,4 at all measurement methods. The average TEWL values with PT 3,4 were higher than those with PT 0,2, especially on the 4-h course. This distinction may derive from the shape and size of the skin impairment achieved by PT 3,4, leading to a mechanical barrier disruption. However, SLS may infiltrate directly into deeper skin layers supported by capillarity. Consequently, no or little penetration through the epidermis and interaction with its structures occurs, which is responsible for irritant skin reactions. The SLS dose in the upper skin layers is therefore lower at these PTs. The lower remaining dose of SLS also explains this distinction, especially for the VS. Additionally, there are presumed reactions in deeper layers of the epidermis and dermis at PT 3,4. Conclusions, In summary, all data suggest a different reaction pattern from the classical irritant response. Therefore, application without any PT seems to be best suited for irritancy skin testing, especially for visual assessment. PTs prior to irritant patch testing have been shown to be unjustifiable. [source]

FS02.8 Patch testing with gold trichloride can give false test results

CONTACT DERMATITIS, Issue 3 2004
Birgitta Gruvberger
Background:, Hydrochloric acid is formed in water solutions of gold trichloride. Hydrochloric acid in contact with aluminium generates hydrogen gas which can reduce and transform trivalent gold to elemental gold. Objective:, To investigate whether patch testing with aqueous gold trichloride can cause false positive (irritant) reactions in patients without contact allergy to gold and false negative reactions in patients with gold allergy. Methods:, 13 patients with and 13 patients without positive patch test reactions to gold sodium thiosulfate were tested with gold trichloride in 2 different vehicles, water and alkaline buffer, using 2 different test techniques, the Finn Chamber technique with aluminium chambers and van der Bend technique with polypropene chambers. Results:, Irritant patch test reactions were obtained with aqueous gold trichloride tested in van der Bend chambers in 10 patients without gold allergy. In gold-allergic patients no positive test reactions were obtained from aqueous gold trichloride in Finn chambers while 2 positive test reactions were obtained from gold trichloride in alkaline buffer tested in van der Bend chambers. Conclusion:, If gold trichloride is patch tested in wrong vehicle and with wrong test technique irritant test reactions may occur which can be misinterpreted as positive allergic reactions in patients without gold allergy as well as negative reactions in patients with gold allergy. [source]

Allergic contact dermatitis to mango flesh

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2004
Sari Weinstein MD
A 22-year-old white female student presented to the Emergency Department with a 2-day history of patchy pruritic erythema of the face, neck, and arms with periorbital edema. The eruption began as an isolated patch of nasal erythema, with subsequent extension to involve the entire face. Within 2 days, fine pinpoint papules were noted on the face, anterior chest, neck, and upper extremities. Periorbital edema was present without intraoral abnormalities or laryngeal changes. An erythematous, mildly lichenified plaque was noted on the ventral left wrist. The past medical history was significant for two similar, milder episodes of allergic reactions of uncertain etiology occurring within the previous 2 months. The previous eruptions resolved after treatment with oral loratodine and topical fluocinonide cream 0.05%. The patient denied any history of contact urticaria or new household or personal hygiene contactants, although she did report frequent ingestion of peeled mangoes. Her brother had a history of eczematous dermatitis. In the Emergency Department, the patient was administered intravenous diphenhydramine and a single 50 mg dose of oral prednisone. She continued treatment with a 5-day course of prednisone, 50 mg daily, with loratodine, 20 mg daily, and diphenhydramine as needed; however, no symptomatic improvement was seen over 4 days. She was then advised to restart fluocinonide cream twice daily. Patch testing was performed to the North American Contact Dermatitis Group Standard Series utilizing methods of the International Contact Dermatitis research group with Finn chambers. Mango skin and mango flesh harvested 5 mm below the skin surface were also placed in duplicate and tested under Finn chambers. Positive (1+) reactions were noted to nickel and p -tertbutylphenol formaldehyde resin, and bullous reactions were found to mango skin and surface flesh in duplicate (Fig. 1). Complete avoidance of mango led to resolution of the initial eruption. The clinical relevance of nickel and p -tertbutylphenol formaldehyde resin was thought to be associated with the wrist lesion immediately below a glued portion of a wristwatch strap and metal clasp. Figure 1. Positive patch test reactions, in duplicate, to mango skin (left column) and mango flesh 5 mm below the skin (right column) [source]