British Association of Dermatologists guidelines for the management of people with chronic urticaria 2021

The overall objective of the guideline is to provide up-to-date, evidence-based recommendations for the management of urticaria. The document aims to: offer an appraisal of all relevant literature up to March 2020, focusing on any key developments address important, practical clinical questions relating to the primary guideline objective provide guideline recommendations and if appropriate research recommendations The guideline is presented as a detailed review with highlighted recommendations for practical use in primary, secondary and tertiary care, in addition to an updated Patient Information Leaflet (PIL; available on the BAD Skin Health Information website, https://www.skinhealthinfo.org.uk/a-z-conditions-treatments/).

Recommendation to include hydroxyethyl (meth)acrylate in the British baseline patch test series

BACKGROUND

(Meth)acrylates are potent sensitizers and a common cause of allergic contact dermatitis (ACD). The frequency of (meth)acrylate ACD has increased with soaring demand for acrylic nails. A preliminary audit has suggested a significant rate of positive patch tests to (meth)acrylates using aimed testing in patients providing a clear history of exposure. To date, (meth)acrylates have not been routinely tested in the baseline patch test series in the U.K. and Europe.

OBJECTIVES

To determine whether inclusion of 2-hydroxyethyl methacrylate (2-HEMA) 2% in petrolatum (pet.) in the baseline series detects cases of treatable (meth)acrylate ACD.

METHODS

During 2016-2017, 15 U.K. dermatology centres included 2-HEMA in the extended baseline patch test series. Patients with a history of (meth)acrylate exposure, or who tested positive to 2-HEMA, were selectively tested with a short series of eight (meth)acrylate allergens.

RESULTS

In total 5920 patients were consecutively patch tested with the baseline series, of whom 669 were also tested with the (meth)acrylate series. Overall, 102 of 5920 (1·7%) tested positive to 2-HEMA and 140 (2·4%) to at least one (meth)acrylate. Had 2-HEMA been excluded from the baseline series, (meth)acrylate allergy would have been missed in 36 of 5920 (0·6% of all patients). The top (meth)acrylates eliciting a positive reaction were 2-HEMA (n = 102, 1·7%), 2-hydroxypropyl methacrylate (n = 61, 1·0%) and 2-hydroxyethyl acrylate (n = 57, 1·0%).

CONCLUSIONS

We recommend that 2-HEMA 2% pet. be added to the British baseline patch test series. We also suggest a standardized short (meth)acrylate series, which is likely to detect most cases of (meth)acrylate allergy.

Recommendation to test limonene hydroperoxides 0·3% and linalool hydroperoxides 1·0% in the British baseline patch test series

BACKGROUND

There is a significant rate of sensitization worldwide to the oxidized fragrance terpenes limonene and linalool. Patch testing to oxidized terpenes is not routinely carried out; the ideal patch test concentration is unknown.

OBJECTIVES

To determine the best test concentrations for limonene and linalool hydroperoxides, added to the British baseline patch test series, to optimize detection of true allergy and to minimize irritant reactions.

METHODS

During 2013-2014, 4563 consecutive patients in 12 U.K. centres were tested to hydroperoxides of limonene in petrolatum (pet.) 0·3%, 0·2% and 0·1%, and hydroperoxides of linalool 1·0%, 0·5% and 0·25% pet. Irritant reactions were recorded separately from doubtful reactions. Concomitant reactions to other fragrance markers and clinical relevance were documented.

RESULTS

Limonene hydroperoxide 0·3% gave positive reactions in 241 (5·3%) patients, irritant reactions in 93 (2·0%) and doubtful reactions in 110 (2·4%). Linalool hydroperoxide 1·0% gave positive reactions in 352 (7·7%), irritant reactions in 178 (3·9%) and doubtful reactions in 132 (2·9%). A total of 119 patients with crescendo reactions to 0·3% limonene would have been missed if only tested with 0·1% and 131 patients with crescendo reactions to 1·0% linalool would have been missed if only tested with 0·25%. In almost two-thirds of patients with positive patch tests to limonene and linalool the reaction was clinically relevant. The majority of patients did not react to any fragrance marker in the baseline series.

CONCLUSIONS

We recommend that limonene hydroperoxides be tested at 0·3% and linalool hydroperoxides at 1·0% in the British baseline patch test series.

Muckle-Wells syndrome without mutation in exon 3 of the NLRP3 gene, identified by evidence of excessive monocyte production of functional interleukin 1β and rapid response to anakinra

We report a man with lifelong urticaria, night sweats, arthralgia and lethargy. He had high levels of inflammatory markers and serum amyloid A, but no identifiable mutation in exon 3 of the NLRP3 (NOD-like receptor family, pyrin domain-1 containing 3) gene, and no relevant family history. We found marked production of functional interleukin (IL)-1 by the patient's monocytes at baseline and after stimulation with lipopolysaccharide. The patient made an immediate response to treatment with an IL-1β receptor antagonist. We propose that this patient has Muckle-Wells syndrome without deafness, occurring de novo. Functional screening for IL-1 production could aid diagnosis in future similar cases.

Failure of omalizumab in cholinergic urticaria

Cholinergic urticaria is one of the more common physical urticarias. Although it is often fairly mild, severe treatment-resistant disease may occur, with significant associated disability. Omalizumab, a monoclonal IgG anti-IgE antibody licensed for use in severe asthma, has recently been used successfully in several types of urticaria, including in one case of cholinergic urticaria. This paper reports a patient with severe cholinergic urticaria, unresponsive to antihistamines and multiple other treatments, whose disease was also unresponsive to omalizumab.

EAACI/GA(2)LEN task force consensus report: the autologous serum skin test in urticaria

Injection of autologous serum collected during disease activity from some patients with chronic spontaneous urticaria (CU) into clinically normal skin elicits an immediate weal and flare response. This observation provides a convincing demonstration of a circulating factor or factors that may be relevant to the understanding of the pathogenesis and management of the disease. This test has become known as the autologous serum skin test (ASST) and is now widely practised despite incomplete agreement about its value and meaning, the methodology and the definition of a positive response. It should be regarded as a test for autoreactivity rather than a specific test for autoimmune urticaria. It has only moderate specificity as a marker for functional autoantibodies against IgE or the high affinity IgE receptor (FcepsilonRI), detected by the basophil histamine release assay, but high negative predictive value for CU patients without them. It is usually negative in other patterns of CU, including those that are physically induced. Positive ASSTs have been reported in some subjects without CU, including those with multiple drug intolerance, patients with respiratory allergy and healthy controls, although the clinical implications of this are uncertain. It is essential that failsafe precautions are taken to ensure that the patient's own serum is used for skin testing and aseptic procedures are followed for sample preparation and handling. CU patients with a positive ASST (ASST(+)) are more likely to be associated with HLADR4, to have autoimmune thyroid disease, a more prolonged disease course and may be less responsive to H1-antihistamine treatment than those with a negative ASST (ASST(-)) although more evidence is needed to confirm these observations conclusively.

Chronic idiopathic urticaria with functional autoantibodies: 12 years on

It is now recognized that approximately one-third of patients with chronic idiopathic urticaria (CIU) have histamine-releasing autoantibodies directed against either the high-affinity IgE receptor or, less frequently, against IgE. However, there are several unsolved problems relating to the role of such autoantibodies in the disease. Additionally, it is not clear whether CIU with autoantibodies can be classified as an autoimmune disease. The detection of patients with autoantibodies also poses challenges. Firstly, the only in vivo method, the autologous serum skin test, is at best 80% sensitive and specific using in vitro basophil histamine release assays as the verum. Secondly, in vitro tests are only done in a small number of research laboratories, and are not widely commercially available, and thirdly, there is some divergence between results obtained by different methods (functional and immunoassays) used to detect patients with autoantibodies. The presence of autoantibodies may be important clinically in a small group of severely affected, treatment-resistant patients, where immunomodulatory treatments may be helpful.

Twice-daily vs. once-daily inpatient dithranol for psoriasis

The aim of this study was to compare the efficacy and tolerability of twice-daily vs. once-daily regimes of dithranol (anthralin) in Lassar's paste. Over a 4-year period, 61 inpatients with stable plaque psoriasis gave informed consent and entered a randomized controlled trial, having twice or once-daily application of dithranol in Lassar's paste as part of otherwise standard Ingram's regime. Primary outcome measurements were time required in hospital, nursing time, changes in total body surface area affected by psoriasis and thickness of a target plaque and in some patients, an assessment of the recurrence of psoriasis. Doctors were blinded as to the regime being used. At entry, mean patient age, lesional surface area and target plaque thickness were comparable in both groups and no patient had received systemic therapy in the preceding 3 months. Forty-two patients completed the study, two (11%) in the twice-daily group withdrawing due to skin irritation or 'burning'. Mean lesional surface area and target plaque thickness were similar in both groups at hospital discharge. Mean (+/- SD) time spent in hospital was not significantly different in each group, being 13.3 (+/- 6.2) days and 13.9 (+/- 4.5) days for the twice-daily and once-daily groups, respectively (P = 0.36). Duration of hospitalization did not correlate with surface area or plaque thickness on admission. Mean (+/- SD) nursing time spent on treatment was significantly greater in the twice-daily group, at 0.82 (+/- 0.33) hours per day compared with 0.51(+/- 0.25) hours per day in the once-daily group. Relapse rate at 6 months was not different between the two groups.

Lymphocytic infiltrates as a presenting feature of Sweet's syndrome with myelodysplasia and response to cyclophosphamide

Sweet's syndrome has a well-recognized association with malignancies, around half of which have been acute myelogenous leukaemia. There are also numerous reports of Sweet's syndrome in association with myelodysplasia. We report two patients with Sweet's syndrome in whom the classical histological appearances were preceded by dermal lymphocytic infiltrates. A literature search using PubMed indicates that this phenomenon has not been previously reported. The cases demonstrate the chronicity of Sweet's lesions in association with haematological disease and the need for repeat biopsies to make the diagnosis. We also describe successful treatment with cyclophosphamide, which adds to the list of second-line drugs that may be used in Sweet's syndrome.

An audit of the use of self-administered adrenaline syringes in patients with angio-oedema

BACKGROUND

Self-administered adrenaline syringes may be prescribed for patients at risk of life-threatening episodes of angio-oedema or anaphylaxis.

OBJECTIVES

To determine whether patients are able to use these syringes appropriately and adequately.

METHODS

Twenty-nine consecutive patients who had been prescribed self-administered adrenaline syringes for severe angio-oedema were recruited. All completed a questionnaire (unsupervised), and were asked to demonstrate how to use a dummy syringe.

RESULTS

Three of 29 (10%) patients had been prescribed syringes in the absence of severe angio-oedema or collapse. Seventeen of 29 (59%) patients had been prescribed two syringes, and 21 of 29 (72%) kept a syringe with them at all times. Twenty of 28 (71%) patients had had the use of a syringe demonstrated to them with the initial prescription, but two of 29 (7%) had never been shown how to use it. Only six of 26 (23%) patients had been told to telephone for an ambulance after using a syringe. Only seven of 29 (24%) patients would use a syringe for an episode of collapse, whereas eight of 28 (29%) would use one for an episode of lip swelling. Nine of 21 (43%) patients had not been warned about adverse effects, although 13 of 20 (65%) given adrenaline had had at least one adverse effect. Of the 25 patients asked to demonstrate their use of a syringe, only 14 (56%) were able to perform all steps correctly, and three (12%) were unable to perform any of the steps. Despite this, all 29 patients felt confident about giving themselves an injection, and most felt more secure having been prescribed syringes.

CONCLUSIONS

As self-administered adrenaline syringes are prescribed for life-threatening events, it is vital that they are given to appropriate patients with adequate written instructions and proper demonstration at the time of the initial prescription. As a result of this study we have developed a more detailed patient information leaflet, and all patients are shown how to use a syringe for a second time when attending the clinic for follow-up.

Methotrexate-responsive chronic idiopathic urticaria: a report of two cases

Chronic idiopathic urticaria (CIU) may be severe and refractory to standard therapies. We describe two patients with CIU, neither of whom had detectable autoantibodies, in whom control of the disease was achieved with methotrexate.

Rituximab in cutaneous B-cell lymphoma: a report of two cases

We report two patients with primary cutaneous B-cell lymphoma who were treated with rituximab, a new anti-CD20 monoclonal antibody. The first patient, who had a diffuse large B-cell lymphoma of the lower leg, achieved an 85% improvement. The second patient, who had a primary cutaneous B-cell lymphoma, which had undergone high-grade transformation and systemic spread, achieved a minor response of approximately 30%. Both patients subsequently relapsed. The first patient achieved complete clearance with a second course of rituximab given with systemic chemotherapy, but again relapsed. Treatment with rituximab has been reported to produce response rates of 48% in relapsed systemic low-grade or follicular lymphoma, but there are no previous reports of the use of rituximab in primary cutaneous B-cell lymphoma.

Schnitzler's syndrome: no evidence for autoimmune basis in two patients

We report two cases of Schnitzler's syndrome in which anti-interleukin-1alpha autoantibodies and functional autoantibodies against the high affinity IgE receptor (FcepsilonRIalpha) or against IgE were absent. One patient responded well to TL-01 phototherapy, a treatment which may be considered in patients with Schnitzler's syndrome if, as is usually the case, they are unresponsive to antihistamine therapy.

The autologous serum skin test: a screening test for autoantibodies in chronic idiopathic urticaria

One-third of patients with chronic idiopathic urticaria (CIU) have circulating functional autoantibodies against the high affinity IgE receptor FcepsilonRI, or IgE. The intradermal injection of autologous serum causes a weal and flare reaction in many patients with CIU, and this reaction forms the basis of the autologous serum skin test (ASST). We have determined the parameters of the ASST which define the optimal sensitivity and specificity for the identification of patients with autoantibodies. Two physicians (R.A. S. and C.E.H.G.) performed ASSTs in a total of 155 patients with CIU, 40 healthy control subjects, 15 patients with dermographism, nine with cholinergic urticaria and 10 with atopic eczema. Patients were classified as having functional autoantibodies by demonstrating in vitro serum-evoked histamine release from the basophils of two healthy donors. There were significant differences (P < 0.001) in the mean weal diameter, weal volume, weal redness and flare area of the intradermal serum-induced cutaneous responses at 30 min between patients with CIU with autoantibodies and either those without autoantibodies or control subjects. The optimum combined sensitivity and specificity of the ASST was obtained if a positive test was defined as a red serum-induced weal with a diameter of >/= 1.5 mm than the saline-induced response at 30 min. For R.A.S. and C.E.H.G., the ASST sensitivity was 65% and 71% and specificity was 81% and 78%, respectively. Using these criteria, the following subjects had positive ASSTs: none of 15 dermographics, none of 10 atopics, one of nine cholinergics and one of 40 controls.

Cutaneous inflammatory cell infiltrate in chronic idiopathic urticaria: comparison of patients with and without anti-FcepsilonRI or anti-IgE autoantibodies

BACKGROUND

Previous studies defining the histopathologic features of patients with chronic idiopathic urticaria (CIU) were performed on wheals of uncertain duration and before the identification of functional autoantibodies against FcepsilonRI and/or IgE, now known to be present in approximately 30% of patients with CIU.

OBJECTIVE

We sought to determine the timing of the inflammatory infiltrate in the wheals of patients with CIU and to detect differences between patients with and without autoantibodies.

METHODS

Immunohistochemistry was used to identify neutrophils (neutrophil elastase), T lymphocytes (CD3), and activated eosinophils (EG2) in biopsy specimens from uninvolved skin and wheals present for less than 4 hours and greater than 12 hours in 22 patients with CIU, as well as in biopsy specimens from the skin of 12 healthy control subjects. Patients were identified as having functional autoantibodies on the basis of their serum-evoked histamine release in vitro from the basophils of 2 healthy donors.

RESULTS

EG2(+), neutrophil elastase+, and, to a lesser extent, CD3(+) cells were found in greater numbers in wheals undergoing biopsy at less than 4 and greater than 12 hours than in uninvolved skin (P <.05). Patients without autoantibodies (n = 12) had significantly more EG2(+) cells in wheals of greater than 12 hours' duration than patients with autoantibodies (n = 10; P =.02). There was no other difference between patients with and without autoantibodies in the cutaneous cellular infiltrate.

CONCLUSION

Neutrophil and eosinophil accumulation occurs early in the evolution of a wheal in patients with CIU, but eosinophil activation may occur later or be more persistent in patients without autoantibodies.

Chronic idiopathic urticaria: comparison of the clinical features of patients with and without anti-FcepsilonRI or anti-IgE autoantibodies

BACKGROUND

Previous studies defining the clinical features of patients with chronic idiopathic urticaria (CIU) were performed before the identification of functional autoantibodies against FcepsilonRI and/or IgE, now known to be present in approximately 30% of patients with CIU.

OBJECTIVE

Our purpose was to determine whether there are differences between patients with and those without autoantibodies in the clinical features or severity of CIU.

METHODS

The clinical features of 107 patients with CIU were evaluated prospectively. Patients were identified as having functional autoantibodies on the basis of the serum-evoked histamine release in vitro from the basophils of 2 healthy donors.

RESULTS

Patients with autoantibodies (31%) had more wheals (P = .005), a wider distribution of wheals (P = .009), higher itch scores for the most severe episodes of itching (P = .002), more systemic symptoms (P = .03), and lower serum IgE levels (P < .0005) than patients without autoantibodies.

CONCLUSION

The presence of autoantibodies indicates a subset of patients with more severe CIU.

Scombrotoxic fish poisoning

We report the case of a 30-year-old patient who developed scombrotoxic fish poisoning after eating cooked fresh tuna. Symptoms included a bright red rash, tightness of the chest, palpitations, anxiety, mild headache and dizziness, all of which resolved spontaneously within 2-3 h. Such poisoning results from the consumption of spoiled fish of the families Scomberesocidae or Scombridae - in particular tuna, mackerel, skipjack and bonito - which contain high levels of histidine. Incorrect storage of fish allows bacterial histidine decarboxylase to convert histidine to histamine. The ensuing symptoms are thought to result from the ingestion of histamine. Scombrotoxic fish poisoning is preventable by the correct handling and refrigeration of these fish.

Anti-Fc(episilon)RI auto antibodies and basophil histamine releasability in chronic idiopathic urticaria

BACKGROUND

Circulating functional autoantibodies to the high-affinity IgE receptor (Fc(epsilon)RI) or to IgE have been found in approximately one third of patients with chronic idiopathic urticaria (CIU).

OBJECTIVE

We sought to compare basophil histamine release and basophil numbers in patients with CIU with and without autoantibodies.

METHODS

Basophil histamine release to the anti-Fc(epsilon)RI mAb 22E7, anti-IgE, and formyl-methionyl-leucyl-phenylalanine (fMLP); basophil numbers; and total cellular histamine were measured in 26 patients with CIU and 18 healthy control subjects. Twelve patients were classified as having functional anti-Fc(epsilon)RI and/or anti-IgE autoantibodies on the basis of their serum-evoked histamine release from the basophils of 2 healthy donors.

RESULTS

22E7 and anti-IgE, but not fMLP, released less histamine from basophils of patients with CIU than from those of control subjects. Mean+/-SEM maximum histamine release to 22E7 from basophils of control subjects and patients with CIU with and without autoantibodies was 38.5%+/-5.0%, 17.9%+/-6.0% (P =.01), and 1.0%+/-0.3% (P <.0001), respectively. Similar results were obtained with anti-IgE, which is dependent on and cross-links cell bound IgE, and 22E7, which directly cross-links the IgE receptor. The mean+/-SEM basophil counts for control subjects and patients with CIU without and with autoantibodies were 52+/-7, 34+/-9 (P =.04), and 5+/-1 (P <.0001) x 10(6) cells/L, respectively, and similar changes were found in measurements of total cellular histamine.

CONCLUSION

Patients with autoantibodies have both markedly reduced basophil numbers and basophil histamine release to factors acting through Fc(epsilon)RI, which indicates either a residual pool of functionally distinct basophils or may be a consequence of desensitization of the Fc(epsilon)RI pathway.

The intradermal effects of the H3 receptor agonist R alpha methylhistamine in human skin

We have investigated the possible existence of the H3 histamine receptor in human skin with the highly selective ligands R alpha methylhistamine (RAMHA) (H3 agonist) and thioperamide (H3 antagonist). We compared the intradermal effects of RAMHA with histamine, and studied their potential modulation by the H1 antagonist terfenadine, and H2 antagonist cimetidine. The effects of RAMHA and thioperamide on codeine phosphate-, substance P- and histamine-induced weal and flare responses were also studied. RAMHA produced dose-related weal and flare responses that were approximately 10- and fivefold less, respectively, than responses to histamine. Flare responses to RAMHA were significantly inhibited by oral terfenadine (P < 0.05). Weal and flare responses to histamine after oral cimetidine showed much intersubject variation, and cimetidine did not significantly alter either RAMHA- or histamine-induced weal and flare responses. Codeine phosphate-, substance P- and histamine-induced responses were not significantly affected by concurrent administration of RAMHA. Thioperamide was not found to influence codeine phosphate-, substance P-, RAMHA- or histamine-induced effects. RAMHA induces vascular (weal and flare) responses in human skin, and these responses are partially inhibited by terfenadine. There is a trend for RAMHA to have an additive effect to the weal induced by substance P and histamine, although our results largely do not reach statistical significance. Thioperamide does not affect the vascular responses to RAMHA, codeine phosphate, histamine or substance P. We cannot conclude that the effects of RAMHA are induced by H3 receptors on cutaneous endothelial or mast cells.

The effects of topical doxepin on responses to histamine, substance P and prostaglandin E2 in human skin

The tricyclic antidepressant, doxepin, is known to have H1 and H2 antihistaminic effects. Recently, 5% doxepin cream has been marketed in the U.S.A. for treatment of eczematous dermatoses. We investigated the effects of topical doxepin treatment on histamine-, substance P- and prostaglandin E2- (PGE2) induced responses in the skin of normal and atopic subjects. We compared the effects of topical doxepin with those of the oral antihistamine terfenadine. The weal volume and flare area responses to histamine were significantly reduced by treatment with topical doxepin or oral terfenadine in both normal and atopic subjects (P < 0.05). The mean +/- SEM percentage reduction in flare area for 10 micrograms/site of histamine in non-atopics and atopics was 48 +/- 8% and 60 +/- 17% with terfenadine, and 54 +/- 12% and 81 +/- 4% with topical doxepin, respectively. The mean percentage reduction in weal volume for the same dose of histamine in non-atopics and atopics was 70 +/- 9% and 63 +/- 16% with terfenadine, and 96 +/- 2% and 89 +/- 6% with topical doxepin, respectively. The flare but not the weal response to substance P was inhibited by both treatments in all subjects (P < 0.05). The mean +/- SEM percentage reduction in flare area for 200 pmol/site of substance P in non-atopics and atopics was 53 +/- 10% and 73 +/- 4% with terfenadine, and 74 +/- 7% and 75 +/- 4% with topical doxepin, respectively. The cutaneous responses to PGE2 were not affected by either drug. The inhibitory effects of doxepin were as great as those of terfenadine, and doxepin had a significantly greater effect than terfenadine in inhibiting the weal response to histamine and flare response to substance P in normal volunteers (P < 0.05). There was no significant difference between atopics and non-atopics in the percentage reduction of cutaneous responses by oral terfenadine or topical doxepin. Marked sedation occurred in three of the first 10 subjects treated with topical doxepin, necessitating a reduction in dosage for the remaining six subjects. In summary, topical doxepin was as effective as, and sometimes more effective than, a standard dose of oral terfenadine in the inhibition of histamine-induced and axon-reflex-mediated cutaneous responses. The marked sedative effect may limit its clinical use in some patients.

The pathogenesis of chronic idiopathic urticaria

Chronic idiopathic urticaria (CIU) can be extremely disabling and difficult to treat, with little response to antihistamine therapy. The pathogenic mechanisms of the disease are not well understood, but the primary effector cell is the mast cell. Release of mast cell mediators can cause inflammation and accumulation and activation of other cells, including eosinophils, neutrophils, and possibly basophils. Recent work has demonstrated that about one third of patients with CIU have circulating functional histamine-releasing autoantibodies that bind to the high-affinity IgE receptor (Fc epsilon RI) or, less commonly, to IgE; mast cell-specific histamine-releasing activity that has not yet been fully characterized; no identifiable circulating histamine-releasing activity. The mainstay of treatment of CIU consists of antithistamines, but immunotherapy using plasmapheresis, intravenous immunoglobulin, and cyclosporin may be valuable in severely affected patients with treatment-resistant disease. The response to immunomodulation and the recent finding of an association with HLA DR4 lend further support for an autoimmune basis to CIU in some patients.

Angiotensin-converting enzyme (ACE) inhibitors and angio-oedema

Angiotensin-converting enzyme inhibitors (ACEIs) are used increasingly for the treatment of hypertension and chronic heart failure, and they reduce mortality when given after myocardial infarction. Of the patients prescribed these drugs 0.1-0.7% develop angio-oedema, but the association is not widely recognized. In 60% of cases the onset occurs during the first week of treatment; however, it may be considerably delayed. Angio-oedema nearly always occurs on the head and neck, frequently involving the mouth, tongue, pharynx and larynx. The course is unpredictable, and attacks vary in severity from mild to fatal from laryngeal obstruction. Severe ACEI-induced angio-oedema may require emergency treatment with adrenalin and early intubation. The drug should be withdrawn in any patient who presents with ACEI-induced angio-oedema, and treatment continued with an appropriate drug of a different class. Therapy with ACEIs is contraindicated in patients with a prior history of idiopathic angio-oedema, or in patients with hereditary or acquired C1 esterase inhibitor deficiency.

Histamine: the quintessential mediator

Histamine is unique in being the only substance described to date which fulfils all of the criteria established by Dale for an inflammatory mediator. Thus, histamine is known to cause the "Triple Response" of Lewis and to act via H1 and H2 receptors to produce vasodilation and increased vascular permeability; elevated levels of histamine are found in inflamed tissue; histamine is produced and stored in mast cells and there are established mechanisms for histamine release via mast cell surface receptors; and antihistamines alleviate the clinical manifestations of histamine release. There have been several recent advances in our understanding of histamine pharmacology and of the pathomechanisms of chronic idiopathic urticaria (CIU), a disease in which histamine plays an important role. Two new histamine receptors have been identified, the inhibitory (H3) receptor and the intracellular (H(ic)) receptor involved in cell proliferation. There is now evidence that mast cell derived histamine release in patients with CIU is due to an autoimmune disease, mediated by autoantibodies to the alpha-subunit of the high affinity IgE receptor on mast cells and basophils. Removal of these autoantibodies by plasmapheresis, or treatment with intravenous immunoglobulins may cause clinical remission. Cyclosporin A has also been found to be of benefit to some patients with CIU probably due to a mast cell "stabilising" effect, leading to reduced release of histamine and other mediators. This article reviews our current knowledge on histamine, its role, receptors and mechanisms for release.

Minocycline-induced discolouration of the sclerae

We report two patients with minocycline-induced pigmentation of the sclerae. Cutaneous pigmentation is a well-recognized complication of minocycline therapy, but only five cases of pigmentation of the sclerae have been described previously. These five patients have a number of features in common with the two reported here. We propose that these patients represent the most severe end of the spectrum of minocycline-induced cutaneous changes. Patients should be warned about the possibility of the occurrence of pigmentary changes before starting therapy.

Urticarial vasculitis associated with polycythaemia rubra vera

We report a case of urticarial vasculitis as the presenting feature of polycythaemia rubra vera. The cutaneous eruption resolved on correction of the polycythaemia by venesection. To our knowledge this is the first report of such an association.

Contact allergy to gold sodium thiosulfate

100 consecutive patients routinely attending the contact dermatitis clinic were patched tested to gold sodium thiosulfate (GST). 13 patients had a positive patch test to GST, 11 of whom were female, and 12 had pierced ears. There was no correlation with any other substance in the European standard series, although there was a high incidence of nickel sensitivity in all patients (33%). Eczema on the ring fingers and neck was significantly more common in the group positive to GST. 1/2 of the patients with a positive response to GST had symptoms that they felt could be attributed to gold allergy.

Agminate Spitz naevi occurring in an adult after the excision of a solitary Spitz naevus--report of a case and review of the literature

We describe a 21-year-old female who presented with four agminate Spitz naevi close to the scar from a previously excised solitary Spitz naevus, and review the literature since 1987 on widespread and agminate Spitz naevi. Spitz naevi usually present as solitary firm red or brown papular lesions. Agminate Spitz naevi are unusual and they have been reported mainly in children. It is uncommon for Spitz naevi to recur after surgery and far more unusual for a recurrence to occur in an agminate form. Such lesions may mimic multiple satellite and in-transit metastases which can occur in malignant melanoma, and close follow up of any new lesions occurring in this case is intended.

Facial granulomatous lymphoedema and syringomyelia

The term orofacial granulomatosis was introduced for orofacial lesions which resemble Crohn's disease clinically and histologically in patients without gastrointestinal disease. The Melkersson-Rosenthal syndrome and its oligosymptomatic form Meischers granulomatous cheilitis are usually felt to be part of the same spectrum of disease. Oedema usually involves tissues of the lower half of the face. We describe a patient with histological changes consistent with those found in orofacial granulomatosis, but with isolated localized oedema of the right periorbital tissues. The patient also had syringomyelia which has not previously been described in association with orofacial granulomatosis.

Dermatomyositis treated with high-dose intravenous immunoglobulins and associated with panniculitis

Polymyositis and dermatomyositis are idiopathic inflammatory myopathies characterized by subacute symmetrical weakness of proximal limb and trunk muscles. Dermatomyositis is distinguished from polymyositis by the presence of rash. We describe an adult patient with treatment-resistant childhood-type dermatomyositis who made a good response to high dose intravenous immunoglobulins. Additionally, there was evidence of panniculitis which is an unusual histopathological finding in dermatomyositis.

Multiple lentigines confined to psoriatic plaques

The development of naevus spilus-like hyperpigmentation at sites of resolving plaques of psoriasis has been reported previously. Although the mechanism is not understood, PUVA therapy has been implicated in most cases. We report an additional case in which lentigines, confined to sites of resolving psoriasis, occurred following oral PUVA. We also describe similar clinical features in two patients who had not received PUVA, which strengthens the observation that this treatment is not a prerequisite for development of this unusual pattern of pigmentation.