Minimal effect of complete H1 receptor blockade on urticaria pigmentosa

The effect of complete H1 receptor blockade on urticaria pigmentosa was studied in 6 patients. Astemizole 10 mg tds was given for 6 weeks to achieve complete H1 receptor blockade and the response measured by change in force-weal response measurements using two different forces on a dermographic stylus and measuring response as weal diameter. Weal and flare reactions to 8 micrograms histamine were completely abolished by the astemizole but dermographic weal-force responses were reduced only by 12-15% indicating that histamine acting at the H1 receptor plays only a small part in the wealing of urticaria pigmentosa.     

The effect of cetirizine on symptoms and wealing in dermographic urticaria

The effect of cetirizine, 10 mg at night, on dermographic urticaria, was studied in 19 patients. The study design was a randomized, double-blind, crossover comparison with placebo, each treatment being given for 7 days. Patients kept a daily diary of itch and weal severity (100-mm linear analogue scale), and recorded sleep disturbance. The dermographic weal response was measured objectively with a spring-loaded stylus, and the weal threshold calculated from the force/response curve. There was a small, insignificant subjective response to placebo, but no objective response. On cetirizine, the subjective assessment of wealing was reduced from 34.3±6.7 (mean ± SEM, 0–100 scale) to 16.8±4.1 (P= 0.02), itch was reduced from 43.2±6.6 to 19.4±4.1 (P=0.001), and nights disturbed from 46.2 to 8.8% (P=0.03). There was a shift to the right in the position of the force/response curve, and the wealing threshold increased from 24.6±3.2 to 54.7±4.4 g/mm² (P=0.00001), but there was no correlation between change in itch scores and wealing threshold. Cetirizine 10 mg daily is an effective treatment in dermographic urticaria, and its usefulness will depend on the prevalence of unwanted effects.     

In dermographic urticaria H2 receptor antagonists have a small but therapeutically irrelevant additional effect compared with H1 antagonists alone

Two studies of the additional effect of an H₂ receptor antagonist when given in combination with an H₁ antagonist were undertaken in dermographic urticaria. Using a randomized, double-blind, crossover design in 19 patients, a combination of cetirizine (10 mg at night) and ranitidine (150 mg twice daily) was compared with a combination of cetirizine (10 mg at night) and placebo. The addition of ranitidine did not produce any significant difference in linear analogue scores for weal, Itch or sleep disturbance. There was a significant depression of the frictional force/wealing response curve with an increase in wealing threshold (P<0.0001) following the addition of H₂ blockade. The wealing threshold was 54.7 ± 4.4 (mean ± SEM) g/mm² for the H₁ antagonist alone, and 73.2 ± 5.7 for the combination of H₁ and H₂ antagonists. In a second similar study involving nine different patients, comparing terfenadine (120 mg twice daily) with a combination of terfenadine and ranitidine (150 mg twice daily), the weal threshold was 59.8 ± 6.6 for the H₁ antagonist alone, and 73.0 ± 6.4 for the combination of H₁ and H₂ antagonists. Thus, in dermographic urticaria, adding an H₂ antagonist to treatment with a potent H₁ antagonist gives a small, significant reduction in wealing response, but no symptomatic benefit. We conclude that involvement of the H₂ receptor in this urticarial disease is minimal, and does not justify the use of H₂ receptor antagonists.     

Assessment of the duration of action of terfenadine on histamine induced weals

In this study we aimed to quantify the reduction in area, perimeter and thickness of histamine induced weals 12, 18 and 24 h after a single oral dose of 120 mg terfenadine. Ten healthy volunteers were given 120 mg of terfenadine or placebo in a double-blind randomized two-period cross-over study. Twenty micrograms of histamine were then injected intradermally at 12, 18, and 24 h. The thickness of the resulting weal was measured by an A-scan pulsed ultrasound device. The area and perimeter of the resulting weal and flare were measured by tracing onto acetate sheets and using a digitizing tablet linked to a microcomputer. Just before each dose of histamine was injected, blood was taken to measure the level of the major metabolite of terfenadine. There was a significant difference between terfenadine 120 mg and placebo in the area and perimeter of the weal and the area and perimeter of the weal and flare at 12, 18 and 24 h, but no significant difference in weal thickness. Thus, terfenadine suppresses the wealing response caused by intradermally injected histamine over a 24 h period. It may be possible, therefore, to use a once daily dose of terfenadine.     

Characterization and analysis of skin wealing by computerized non-linear regression

Weal formation in human skin may be induced by histamine, histamine releasers and other inflammatory mediators. Weals occur spontaneously in chronic urticaria, and in response to frictional pressure in dermographic urticaria. We present an improved method for the analysis of wealing in human skin by the use of non-linear regression. The method has the advantage of speed, and by the use of non-linear regression permits the full characterization of the response curves. The time course of histamine-induced wealing is a double exponential function corresponding to the separate components of weal appearance and disappearance. Dermographic wealing corresponds to an increasing exponential function with increasing pressure. The method of computerized nonlinear regression is a considerable advance on previous methods for the analysis of urticarial wealing, the effect of vasoactive agents, and their therapeutic action.     

Clinical and immunohistological characterization of cutaneous lesions in chronic lymphocytic leukaemia

The effects of the H I receptor antagonists astemizole and chlorpheniramine on dermographism were compared in a double-blind study in sixteen patients. Both drugs resulted in a parallel and significant depression of the dermographic force-response curve and an elevation of the weal-force threshold, but the changes were greater in the patients receiving astemizole (a maximal potency shift of 74% for astemizole and 37% for chlorpheniramine). Subjective itch (10 cm line) and frequency of dermographic episodes were also reduced more by astemizole than by chlorpheniramine. The effect of astemizole was greater at 4 weeks than at 2 weeks, whereas the effect of chlorpheniramine had decreased at 4 weeks. The effect of astemizole but not chlorpheniramine was still apparent 4 weeks after treatment had been stopped. Since the degree of residual dermographism was comparable despite great differences in histamine weal inhibition a vasoactive mechanism in addition to that mediated by histamine must be involved in dermographic urticaria.     

The effect of H1 and H2 receptor antagonists on the dermographic response

The effect on dermographic wealing of an H1 and H2 receptor antagonist was studied separately and in combination. a double-blind protocol was used and dermographism was measured as the diameter of weal response to a measured force. Both H1 and H2 antagonists had a small but non-significant effect, but the combination of H1 plus H2 antagonist had an approximately additive effect which was significant. Although this indicates a role for H2 receptors in dermographism it does not establish the degree of involvement, nor whether H2 antagonists necessarily have any advantage over a potent H1 blocker alone in the treatment of dermographism.     

The antipruritic effect of a sedative and a non-sedative antihistamine in atopic dermatitis

A double-blind, randomized, cross-over study was carried out on the effect of a sedative and a non-sedative antihistamine on 25 adults with atopic dermatitis. Intensity of itch was recorded using a computerized method for self-assessment (Pain-Track) and using conventional visual analogue scales. The antipruritic effect of 3 days of treatment with the non-sedative H1 antagonist terfenadine (60 mg b.i.d.) and with the sedative antihistamine, clemastine (2 mg b.i.d.) did not differ from that found with the placebo. Our findings support the view that histamine is not of importance in the pathogenesis of itch in atopic dermatitis.     

Efficacy of H, antihistamine, corticosteroids and cyclophosphamide in the treatment of chronic dermographic urticaria

H, antihistamines relieve urticaria by blocking the action of histamine on the target tissue, while demonstration of autoantibodies in the sera of a proportion of the patients having chronic idiopathic urticaria, use of immunosuppressive drugs for the treatment of these patients has acquired the greater rationality. We evaluated the role of corticosteroids and cyclophosphamide in the treatment of chronic dermographic urticaria. Twenty-five patients, 13 males and 12 females, between 18-53 years in age, having chronic dermographic urticaria were taken up for this study. The patients were divided into three groups. Group I patients (n=9) were treated with cetirizine hydrochloride 10 mg per day orally, group II patients (n=7) were treated with betamethasone 2 mg along with cyclophosphamide 50 mg along with cetirizine 10 mg per day for a total period of 4 weeks. The patients were evaluated every week to record the therapeutic response and side effects, and then followed up without treatment for a period of 6 months to look for recurrence of the urticaria, if any. Six patients in group I and all the patients in group II and group III had complete remission while the remaining patients in group I had partial relief. The side effects included drowsiness in 4 patients. All the patients in group II had weight gain, 4 patients had acne and 2 patients developed cushingoid features. Majority of the patients relapsed within 3 days after stopping the treatment. Supplementation of the treatment with oral corticosteroids or cyclophosphamide was more effective in controlling the symptoms as compared to cetirizine alone. But a four weeks supplementation was not adequate for preventing the relapses when the drugs were withdrawn.     

Quantitative time course study of the skin response to histamine and the effect of H1 blockers. A 3-week crossover double-blind comparative trial of cetirizine and terfenadine

A controlled, randomized, double-blind, crossover study was performed in 10 healthy volunteers to compare changes of cutaneous blood flow values (CBFV) determined by laser Doppler flowmetry before and after intake of a capsule containing either 10 mg cetirizine or 60 mg terfenadine. After the determination of the initial response to the anti-H1 agents, drugs were taken daily (cetirizine 10 mg, terfenadine 120 mg) over a 3-week period and the cutaneous response to histamine and saline was evaluated weekly, exactly 4 h after the last drug intake. The following significant variations were observed (analysis of variance for repeated measurements, p less than 0.05): (1) there is a decrease of histamine-induced wheal and flare under antihistamines (anti-H1), cetirizine being more potent than terfenadine; (2) CBFV, measured on the usual flare area, i.e. at 1 cm of the site of agonist injection, decreased after drug intake. There was a gradual increase of the CBFV inhibition over the 3-week follow-up, cetirizine being more effective than terfenadine, and (3) at the site of agonist injection, reduction of the edematous wheal was associated with significant increases of CBFV after drug intake. This quantitative pharmacologic in vivo assay on the agonist action indicates that at lower doses, cetirizine has a significantly higher anti-H1 activity than terfenadine and that this effect is maintained over a 3-week period. There was no tachyphylaxis.     

Start and end of the effects of terfenadine and astemizole on histamine-induced wheals in human skin

A study was made of effects of two antihistamines, terfenadine (60 mg twice daily) and astemizole (10 mg once daily) on wheals induced by histamine dihydrochloride (10 mg/ml) in the prick test on the upper back of 15 healthy students. The suppressive effects of terfenadine on the histamine wheal appeared earlier (2 h), and disappeared earlier (within 1 day) than those of astemizole (3 days and 28 days, respectively). No difference between the maximal effects of the two drugs was seen.     

Failure of terfenadine in relieving the pruritus of atopic dermatitis

We report the results of a double-blind, placebo-controlled, cross-over study of terfenadine 120 mg twice daily for pruritus in atopic dermatitis. Twenty-eight subjects with chronic atopic dermatitis received both terfenadine 120 mg b.d. and placebo each for a period of 1 week. Response was recorded by the subjects using visual analogue scales for severity of pruritus twice daily for the last 4 days of each treatment phase. There was no benefit from terfenadine.     

Cold urticaria with persistent weals

A patient with cold urticaria is described in whom weals appeared immediately after an ice cube test for 3 min and persisted for a week as a red, tender swelling. The duration of the oedema was dependent on the intensity of the immediate reaction. If the immediate wealing was blocked by treatment with an oral antihistamine 3 h before the ice cube test, no delayed reaction was seen. Antihistamines given after the immediate wealing had occurred did not influence the delayed reaction. Reactions to intradermally injected histamine, prostaglandin E, kallikrein, serotonin and serum appeared normal.     

FACTITIOUS WEALING AT THE SITE OF PREVIOUS CUTANEOUS RESPONSE

SUMMARY.— When a weal evoked as a cutaneous allergic response has disappeared, that area of skin, although appearing normal, shows factitious wealing: this tendency persists for 72–96 hr. The phenomenon is present after weals caused by positive intradermal prick tests from various substances, after weals from certain insect bites, and on the site of fading lesions of acute urticaria. Weals caused by intradermal histamine are not followed by this factitious wealing, nor is it present on skin which has been the site of a weal in chronic urticaria.     

Photochemotherapy (PUVA) in the treatment of urticaria pigmentosa

Eight patients received PUVA for mastocytosis. Five women had typical adult-onset urticaria pigmentosa, without evidence of systemic disease. Another woman had suspected hepatic involvement while the remaining female had early-onset familial urticaria pigmentosa with morphologically atypical mast cells. The only male patient had cirrhosis with hepatic deposits of mast cells in addition to polycythaemia rubra vera. In all patients, except the man with systemic disease, there was reduced pruritus and wealing and partial to almost complete fading of the macules. The manifestations of urticaria pigmentosa recurred after treatment was discontinued. In both lesional and uninvolved skin there was no significant change in either the mean mast cell counts or mast cell ultrastructure after an average of twenty-seven PUVA exposures. In addition, PUVA did not cause a significant alteration in the histamine content of the skin. The beneficial effect of PUVA in urticaria pigmentosa therefore does not appear to be directly related to a change in mast cell numbers or morphology, or to the histamine concentration in the skin. Urticaria pigmentosa usually presents as a generalized maculo-papular rash which urticates on rubbing (Darier's sign). Many patients are troubled only by the unsightliness of the rash while some complain of pruritus, wealing or flushing. These symptoms are attributed to the release of histamine by mast cells which characteristically occur in increased numbers in the dermis. Symptomatic treatment is often unrewarding, but favourable results have been claimed for cimetidine with or without Hi blockers (Hirschowitz & Groarke, 1979; O'Laughlin & Bredfeldt, 1980) and for oral disodium cromoglycate (Soter, Austen & Wasserman, 1979; Czarnetski & Behrendt, 1981). In 1978, Christophers and colleagues reported that photochemotherapy (PUVA) produced symptomatic relief in all of ten adult patients with typical urticaria pigmentosa. Similarly encouraging results were subsequently reported from other centres (Ortonne et al., 1980; Allevato, Donatti & Cordero, 1980; Granerus, Roupe & Swanbeck, 1981; Väätäinen, Hannuksela & Karvonen, 1981). In this study we examined the effects of PUVA in eight adult patients with urticaria pigmentosa. Although PUVA produced a moderately good clinical response in seven out of these eight patients (reduced pruritus, reduced wealing and faded macules) quantitative studies failed to reveal a consistent effect of PUVA on either the mast cell population density or the histamine concentration in both lesional and clinically uninvolved skin. The findings arc discussed in relation to existing information concerning the effect of ultraviolet radiation (U VR) on mast cells and other constituents of the skin.     

The skin as a target organ for the investigation of antiallergic drugs: comparison between cetirizine and terfenadine.

Two double-blind clinical pharmacology studies were performed in atopics in order to compare the inhibitory effects of cetirizine (CTZ) 2 HCl and terfenadine (TER) on histamine and antigen-induced skin reactions. In the first study, the subjects took single intakes of CTZ 10 mg and TER 60 mg. In the second study, they took CTZ 10 mg once a day and TER 60 mg b.i.d. for 3 weeks. CTZ was more effective than TER in inhibiting histamine skin reactivity. CTZ and TER were equally effective in inhibiting antigen-induced reactions. There was no tachyphylaxis, either for CTZ or for TER.     

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 10μ/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.     

Inhibition of photosensitivity in erythropoietic protoporphyria with terfenadine

The effect of terfenadine on the response to irradiation with blue light was measured in seven patients with erythropoietic protoporphyria. Terfenadine caused significant inhibition of the immediate flare reaction, but did not alter the erythemal response localized to the irradiation sites. Treatment with beta-carotene had no effect on the flare and erythemal responses. However, the flare reaction was still inhibited by terfenadine during treatment with beta-carotene. These results show that histamine release is involved in the mechanism of porphyrin photosensitivity. H1 receptor antagonists may be of use in the treatment of patients with erythropoietic protoporphyria.     

Rupatadine 10 mg in the treatment of immediate mosquito‐bite allergy

Background People frequently experience wealing and delayed papules from mosquito bites. Wealing is mediated by antisaliva IgE antibodies and histamine. Rupatadine is a new antihistamine effective in allergic rhinitis and urticaria, but the effect on mosquito‐bite allergy is not known. Objective To determine the effectiveness of rupatadine in inmediate mosquito‐bite allergy‐confirmed adult patients. Methods A double‐blind, placebo‐controlled, cross‐over study was performed with rupatadine 10 mg and matched placebo in 30 mosquito‐bite‐sensitive adults. The mean age was 37 years and the subjects had suffered from harmful mosquito bites for a mean of 15 years. Either rupatadine or placebo was taken at 08:00 am for 4 days, followed by a 5 day wash out period and then alternative treatment was given for 4 days. On day 3, in both drug periods the subjects received two Aedes aegypti mosquito‐bites on the forearm. The size of lesions and intensity of pruritus [visual analogue scale (VAS)] were measured after 15 min bite reaction. Results Twenty‐six subjects were analysed for efficacy. The size of the 15 min bite reaction under placebo was of 106 mm² and under rupatadine, of 55 mm². This is a significant decrease (48%; P = 0.0003). The accompanying pruritus decreased from 60 (VAS; median) under placebo to 47.5 under rupatadine, which also is a significant (P = 0.019) difference. There was no significant (P = 0.263) difference in adverse events under rupatadine and placebo. Conclusion The present placebo‐controlled study in mosquito‐bite‐sensitive adults shows that rupatadine 10 mg prophylactically given is an effective treatment for the mosquito‐bite wealing and skin pruritus.     

Localized periorbital edema induced by Ibuprofen

We documented localized periorbital edema in one patient with ibuprofen sensitivity without underlying chronic urticaria. The reaction developed one hour after ingestion of 200 mg of ibuprofen. No systemic symptoms were observed. No other NSAIDs did not induce symptoms. This patient was able to tolerate doses of ibuprofen after pretreatment with terfenadine. These observations suggest that histamine played a central role in this ibuprofen-induced skin reaction. Treatment with terfenadine enabled the patient to tolerate ibuprofen without experiencing any side effects. To the best of our knowledge, this is the first reported case of periorbital edema induced by ibuprofen.