In this study, allergic reactions to systemic or intralesional corticosteroids were characterized, and skin tests utilized in the diagnosis of corticosteroid allergy. Five patients who had developed a rash when treated with systemic or intralesional hydrocortisone, methylprednisolone, prednisolone or betamethasone, were challenged with oral or intra-articular corticosteroid preparations, and skin tested. Upon provocation the patients reacted with diffuse erythema principally on the trunk or on the face. The erythema appeared within a period ranging from a few hours to 24 h and faded in 1-3 days. On patch testing, one patient reacted to prednisolone and methylprednisolone, which induced a positive response upon provocation, and two patients were positive to Pivalone. Patients who were sensitive to hydrocortisone or methylprednisolone, as judged by anamnestic data and provocations, reacted to these corticosteroids in the intradermal tests. Allergy to betamethasone could not be verified by intradermal or patch tests. A combination of intradermal and patch tests is recommended when allergy to systemic or intralesional corticosteroids is suspected. If these skin tests remain negative, provocation is the method of choice.

Gold sodium thiosulphate (GSTS) in patch test series commonly yields positive reactions. In this study of dental patients, the clinical relevance of these positive reactions, the suitability of gold compounds as patch test materials, and value of the lymphocyte proliferation test in gold contact allergy, were evaluated. The frequency of positive patch test reactions to GSTS was 12.4% in the dental series. Fifty-two patients, only two of whom were male, were studied. Thirteen (25%) had had symptoms from jewellery or dental restorations. However, in most cases gold allergy was subclinical. A 10% aqueous solution of gold sodium thiomalate (GSTM) was almost as good as 0.5% GSTS in petrolatum as a marker of gold contact allergy, but 0.001% potassium dicyanoaurate (PDCA) yielded a high percentage of false-negative results. Seventy-three per cent of the subjects with positive patch tests to GSTS responded to gold compounds in vitro in the lymphocyte proliferation test, whereas 13 controls without gold contact sensitivity were negative. Consistent results in skin and lymphocyte proliferation tests provide support for the concept that gold salt-induced 'allergic-like' reactions are truly allergic in nature.

Gold compounds are widely used in the treatment of rheumatoid arthritis. Mucocutaneous side-effects leading to the discontinuation of medication are common with these drugs. We investigated whether allergic mechanisms are involved in dermatosis induced by gold sodium thiomalate (GSTM). Thirteen gold dermatosis patients, 15 arthritis patients without any side-effects from GSTM and 11 healthy controls participated in the study. Venous blood lymphocytes from these subjects were cultured with GSTM and gold sodium thiosulphate (GSTS) in the lymphocyte proliferation test (LPT). In some cases, interferon-gamma-producing cells were enumerated in vitro (T-cell ELISpot). The subjects were also patch-tested with GSTM and GSTS. The LPT to either GSTM, GSTS or both was positive in 12 of 13 patients with gold dermatosis. In the arthritis patient group without side-effects from gold, the LPT gave two false-positive results and in the healthy control group the LPT was falsely positive with one subject. T-cell ELISpot was positive in four of six gold dermatosis patients and negative in the arthritis and healthy control groups. Only one patient who also developed contact dermatitis from gold jewellery was positive to gold in the patch test. These results indicate that gold dermatosis is mediated, at least in part, by allergic mechanisms and that the LPT is of value in the diagnosis of gold dermatosis.

Pivalone/tixocortol pivalate commonly yields positive reactions in the patch test series. The clinical relevance of these positive reactions was investigated in more detail. In the standard patch test series 5.6% (73 of 1306) of the patients were positive to corticosteroids, 5.2% to 0.1% tixocortol pivalate in ethanol (Pivalone nasal spray diluted 1:10) and 2.3% to 1% hydrocortisone butyrate in ethanol. Some of the patients were tested in parallel with Pivalone and 1% tixocortol pivalate in petrolatum. The former test reagent yielded some false-positive reactions, whereas with the latter, some allergic responses were missed. Intradermal tests with the succinate esters of hydrocortisone, methylprednisolone and prednisolone were performed with 52 patients positive to Pivalone. Of these 76.9% (40 of 52) were positive in the intradermal tests; 38 to hydrocortisone, 35 to methylprednisolone and 30 to prednisolone. Twelve patients who had been positive in the intradermal tests were challenged orally with corticosteroids and they all showed positive reactions to hydrocortisone, methylprednisolone or prednisolone. The patients developed localized reactions at the sites of previous eczema or positive skin tests or diffuse erythema or exanthema. The oral doses of hydrocortisone eliciting positive delayed skin reactions ranged from 20 to 200 mg. Reactivity to tixocortol pivalate is closely related to sensitivity to hydrocortisone, methylprednisolone and prednisolone, but high oral doses of these corticosteroids may be required to produce allergic symptoms.

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