Suppression of wheal and flare in histamine test by the main H1 antihistamines commercialized in Brazil

Background:Several dermatoses are mediated by histamine, such as urticaria, angioedema, and papular urticaria. There are no Brazilian studies comparing the potency of antihistamines.Objectives:To evaluate the tolerability and efficacy of the main commercial brand and generic H1 antihistamines, regarding the suppression of the wheal and flare to the histamine test.Methods:A quasi-experimental, open study with 10 healthy adults submitted to the histamine test on the ventral aspect of the forearms. After 20 minutes, wheal and flares were measured. The tests were performed after two hours of intake of dexchlorpheniramine, hydroxyzine, levocetirizine, fexofenadine, cetirizine, loratadine, ebastine, desloratadine, epinastine and rupatadine, as well as generics of loratadine, cetirizine and fexofenadine.Results:All antihistamines presented a reduction in the wheal compared to the control (p <0.02), as well as in the flare, except for rupatadine (p = 0.70). In the internal comparison, cetirizine, fexofenadine, epinastine, levocetirizine, dexchlorpheniramine and hydroxyzine were the most potent, with no difference between them (p > 0.1). As for halo, cetirizine, epinastine, hydroxyzine and fexofenadine were the most potent, with no difference between them (p > 0.1). The most common adverse effect was drowsiness, which was more prevalent among first-generation drugs (p < 0.01). Generic loratadine, fexofenadine and cetirizine halos were higher than their controls (p >0.03)..Study limitations:A single-center study evaluating only aspects related to histamine.Conclusions:Brazilian commercial antihistamines presented different profiles of inhibition of wheal and flares in the histamine test, as well as adverse effects. Generic loratadine, fexofenadine and cetirizine presented larger flares than brand drugs.     

Multiple H1-antihistamine-induced urticaria

H₁‐antihistamines are widely used in the treatment of various allergic diseases. Particularly, a cornerstone of the management of chronic idiopathic urticaria is treatment with H₁‐antihistamines. However, a few cases of H₁‐antihistamine‐induced urticaria have been reported. A 34‐year‐old woman presented with a 4‐month history of recurrent urticaria, which was prominently exacerbated by the administration of H₁‐antihistamines. The patient consented to a provocation test of fexofenadine among drugs including cetirizine and hydroxyzine, which were suspected of inducing severe symptoms in episodes. One hour after challenge with 12 mg fexofenadine (one‐fifth of the therapeutic dose), a urticarial reaction rapidly developed on nearly the entire body with remarkably increased levels of plasma histamine (190 nmol/L) and plasma leukotriene B4 (150 pg/mL). In challenge tests with other antihistamines, generalized urticaria occurred 5 and 1 h after intake of 10 mg loratadine and 10 mg bepotastine, respectively, whereas challenges with chlorpheniramine, mequitazine and azelastine were all negative. Skin prick tests with H₁‐antihistamines used in the challenges were all negative, indicating that the urticarial reactions after challenges with the causative drugs might not be immunoglobulin E‐mediated. Among the causative drugs in our case, cetirizine and hydroxyzine are the piperazine derivatives, whereas fexofenadine, bepotastine, ebastine and loratadine are the piperidine derivatives. The chemical structures of both derivatives are very similar. Therefore, in this case, H₁‐antihistamine‐induced urticaria may have been due to cross‐reactivity between metabolites of these drugs, but not to drugs before metabolization. Hypersensitivity to H₁‐antihistamines should be considered when urticarial lesions worsen after H₁‐antihistamine treatment.     

Plasma concentration of selected neuropeptides in patients suffering from psoriasis

The aim of this study was to evaluate plasma levels of substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) during psoriasis course. METHODS: Seventy-three patients with psoriasis and 32 healthy volunteers were included. Detailed demographic and disease anamnesis was obtained from every patient. The disease severity was assessed using the Psoriasis Area and Severity Index score. Plasma levels of SP, CGRP, VIP and NPY were measured radioimmunologically. RESULTS: Plasma levels of SP and NPY did not significantly differ between patients with psoriasis and controls (median SP: 52.8 and 57.9 pg/ml, respectively; P = 0.32; median NPY: 8.5 and 8.2 pg/ml, respectively; P = 0.67). CGRP plasma concentration was significantly elevated in psoriatic individuals both before (median 43.1 pg/ml) and after treatment (median 45.4 pg/ml), in comparison with healthy donors (median 13.5 pg/ml; P < 0.01 and P = 0.03, respectively). Treatment did not significantly influence plasma CGRP levels (P = 0.3). Median VIP plasma concentration in psoriatics before treatment was significantly higher compared with healthy controls (medians 66.9 and 60.1 pg/ml, respectively; P = 0.04), but the therapy resulted in significant decrease in VIP plasma level (median 19.0 pg/ml; P < 0.001). In psoriatic patients significant correlations were noted between NPY and VIP (R = 0.34; P < 0.01), and VIP and CGRP plasma levels, both before (R = 0.28; P = 0.03) and after the treatment (R = 0.44; P < 0.01). CONCLUSIONS: Based on our results and previous literature data it could be suggested that neuropeptides may be involved in the development of psoriatic lesions.     

Efficacy and safety of antihistamines in allergic skin disorders

Background For patients with urticaria, H₁-antihistamines remain the gold standard medical treatment of choice. They act by blocking H₁ receptors on the vascular endothelial cell surface. Newer, non-sedating antihistamines such as loratadine also act to some extent by blocking the release of histamine from mast cells, basophils and human skin tissue. Efficacy All of the newer antihistamines (loratadine, terfenadine, astemizole and cetirizine) have been shown to have comparable efficacy to the classic sedating antihistamines and to be significantly superior to placebo in terms of symptom improvement. Loratadine has been shown to be at least as effective as the other non-sedating agents and cetirizine. Antihistamines also have a potential benefit in the management of patients with atopic dermatitis. In two studies, loratadine was found to be significantly superior to placebo in the reduction of pruritus. Safety In terms of safety, the newer antihistamines have important differences. Cetirizine, for example, causes dose-related sedation and functional impairment compared to placebo. In contrast, loratadine has no such sedative effects. Terfenadine and astemizole have also been shown to be free of sedative effects, but exceeding the recommended dose of either may increase the risk of a serious cardiac arrhythmia, torsades de pointes. Plasma levels of both terfenadine and astemizole may also be increased as a result of interaction with various drugs. In contrast, loratadine has not been shown to induce ECG changes, even at doses of 40 mg o.d. for 90 days.     

Second- and third-generation antihistamines in the treatment of urticaria

ABSTRACT: Chronic urticaria is mainly idiopathic in nature and can be difficult to treat. While less responsive to antihistamine therapy than acute urticaria, antihistamines still play a key role in the management of symptomatology. While many of the antihistamines still commonly used to treat urticaria are first generation H₁ antagonists (e.g., diphenhydramine, hydroxyzine), the more recently developed second-generation agents (e.g., loratadine, cetirizine) and their metabolites—the third-generation antihistamines (e.g., fexofenadine, norastemizole, descarboxyloratadine)—possess many of the desirable clinical effects of the first-generation agents with a more tolerable side effect profile. This review discusses the advantages and disadvantages of each of the various second- and third-generation agents available, and presents some of the data showing the differences among these agents in the treatment of chronic urticaria.     

Occurrence of substance P,vasoactive intestinal peptide,and calcitonin gene-related peptide in dermographism and cold urticaria

Summary Substance P (SP), calcitonin gene-related peptide (CGRP), and vasoactive intestinal peptide (VIP) were assayed in lesions and normal skin of patients with dermographism and cold urticaria utilizing suction-induced blisters. There was no difference in SP and VIP concentrations between challenged and control skin of urticaria patients. On the whole, however, the concentration of both neuropeptides, and VIP in particular, was higher in the urticaria patients than in control subjects. CGRP levels were not increased. SP and VIP in blood samples from veins draining challenged skin areas were below the detection limit. It is concluded that SP and VIP may potentiate histamine in wheal formation and thus contribute to the increased reactivity of the skin to trauma and temperature changes in patients with physical urticaria.     

Loratadine and cetirizine in the treatment of chronic urticaria

Aim This study was designed to compare loratadine and cetirizine in controlling the symptoms of chronic urticaria. Subjects One hundred and sixteen adult patients with chronic urticaria. Methods In this double-blind study the patients were randomly divided into three therapeutic groups: 38 received loratadine (10 mg), 40 cetirizine (10 mg) and 38 placebo tablets once daily for 28 days. Steroid-dependent subjects and patients with physical urticaria or with angioncurotic hereditary oedema as well as pregnant or breast-feeding women were excluded from the study. A suitable wash-out period was observed in case of previous treatments for the same disease. Itching, erythema, number of lesions and diameter of the largest one were evaluated according to a scale from 0 (absent) to 3 (severe). The minimum entry study score for itching plus number of lesions had to be at least equal to three. Control visits were scheduled after 3, 7 and 14 days of therapy. Symptoms, disease status, therapeutic response, side effects and compliance were evaluated at each visit. Diary cards were filled in by patients at home. Results Active drugs compared to placebo significantly reduced global clinical symptoms (p < 0.05). Loratadine was more rapid in developing its activity than the other two agents (p < 0.01 at day 3). Each single symptom showed the same trend. At the end of the study 24 (63%) patients treated with loratadine, 18 (45%) with cetirizine and 5 (13%) with placebo were free from symptoms. Four failures occurred with loratadine, six with cetirizine and seventeen with placebo. The tolerability profile was similar for all three groups. One patient receiving cetirizine dropped out due to severe gastric pain. Conclusions Loratadine is more active and safer than cetirizine in the treatment of chronic urticaria.     

Effects of acrivastine, loratadine and cetirizine on histamine-induced wheal and flare responses

It is accepted that studies evaluating histamine-induced wheal and flare reactions in the skin represent a simple and reliable method for demonstrating pharmacodynamic activity and pharmacokinetics of the H1-receptor antagonists. In this study, the effects of single oral doses of acrivastine (8 mg), loratadine (10 mg) and cetirizine (10 mg) on the histamine-induced wheal and flare reactions were compared in 60 healthy volunteers. The wheal and flare responses were produced by prick test using 1% histamine solution. Measurements were performed before the ingestion of antihistamines (baseline values) and afterwards at 15, 30, 90, 240, 360 min and 24 h. The values obtained for each antihistamine were compared with each other and with baseline values. Cetirizine was found to be superior to acrivastine and loratadine for the suppression of wheal and flare responses at 240, 360 min and 24 h (P < 0.05) and acrivastine was superior to the other two antihistamines for the suppression of flare response at 30 min (P < 0.05). Our results indicate that a single dose of cetirizine provides a more effective and long acting suppression on wheal and flare reactions in urticaria when compared to acrivastine and loratadine.     

Treatment of Urticaria

Urticaria is a cutaneous syndrome characterized by dermal edema (wheal) and erythema (flare) that blanches with pressure. The lesions typically last less than 24 hours and are usually pruritic. In 1983, Christensen and Maibach summarized the theory behind the use of histamine H₁ receptor antagonists (antihistamines) in clinical dermatology. These agents remain the mainstay of treatment for urticaria. This article reviews the medical literature on the effectiveness of antihistamines in urticarial syndromes, including acute, chronic idiopathic and the physical urticarias. Older antihistamines, such as chlorpheniramine and hydroxyzine, are effective in the treatment of urticarias, but they also have marked sedative and anticholinergic effects. Newer nonsedating antihistamines (second-generation antihistamines) have been developed that have reduced adverse effects because they do not cross the blood-brain barrier; these agents (acrivastine, cetirizine, loratadine, mizolastine, fexofenadine, ebastine, azelastine and epinastine) cause significantly less sedation and psychomotor impairment than their older counterparts. A review of the literature reveals that there are few studies which document the efficacy of second-generation antihistamines in the treatment of acute urticaria, a biologic entity that usually resolves within 3 weeks. We did not identify controlled studies that suggested superiority of any antihistamine in the treatment of acute urticaria. Loratadine or cetirizine, and possibly mizolastine, appear to be treatments of choice for chronic idiopathic urticaria. For symptomatic dermatographism, the combination of an antihistamine and an H₂ antagonist, e.g. chlorpheniramine and cimetidine, appears to be effective. Very few studies have been conducted on the use of antihistamines in the treatment of cold, cholinergic, and pressure urticaria. Antihistamines are the mainstay of urticarial therapy. This evidence-based review suggests that there are efficacy differences between newer, nonsedating antihistamines and older agents in some forms of the disorder. Clearly, further well-controlled clinical trials in larger numbers of patients are needed to clarify the role of these agents in the treatment of urticaria.     

High dose cetirizine: a case report

We report the case of a 46-year-old man who tolerated 50 mg per day of cetirizine for the treatment of chronic idiopathic urticaria. The patient denied any sedation or somnolence and had no difficulty performing routine daily functions including driving. He had tried other antihistamines, including fexofenadine, loratadine, and hydroxyzine without improvement.     

Use and safety of antihistamines in children

ABSTRACT: Although first-generation antihistamines remain popular for the treatment of seasonal allergic rhinitis, atopic dermatitis, and urticaria in children, second- and third-generation antihistamines hold clear advantages over the first-generation agents, especially for the pediatric patient. The less frequent dosing schedule of the second- and third-generation agents makes administration easier for the parent. With less sedation and lower risk of adverse effects, the safety profile of second- and third-generation agents appears superior to that of first-generation agents. After briefly discussing the use of first-generation antihistamines, the pharmacokinetics, safety, and use of the newer antihistamines loratadine, cetirizine, and fexofenadine in the pediatric patient are reviewed.     

咪唑斯汀、氯雷他定及西替利嗪对小鼠变应性接触性皮炎作用的比较研究

目的:比较咪唑斯汀、氯雷他定及西替利嗪对小鼠变应性接触性皮炎(ACD)的抑制作用。方法:建立小鼠ACD模型,采用致敏前及诱发后两种给药方法,口服不同剂量咪唑斯汀、氯雷他定及西替利嗪,观察抑制作用。结果:致敏前开始给药,3种药物均能明显抑制ACD小鼠耳肿胀(P<0.05),但咪唑斯汀的抑制作用强于氯雷他定及西替利嗪(P<0.05);诱发后开始给药,咪唑斯汀组小鼠耳肿胀消退快于氯雷他定及西替利嗪(P<0.05)。结论:咪唑斯汀对小鼠ACD抑制作用强于氯雷他定和西替利嗪。     

Occurrence and distribution of neuropeptides in the human skin. An immunocytochemical and immunochemical study on normal skin and blister fluid from inflamed skin

The content and distribution of substance P (SP), somatostatin, vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP) and neuropeptide Y (NPY) in human skin were investigated. Radioimmunoassay was performed on pooled tissue samples from several regions (fingers, toes, axillas and thighs) and on tissue fluid from spontaneous blisters on inflamed skin. Immunocytochemical localization showed all peptides examined except somatostatin to be present in nerve fibers. Nerve fibers storing SP and CGRP, which were found to coexist, were mostly present as free nerve endings in the superficial part of dermis and in epidermis. SP/CGRP fibers were most abundant in fingers and toes. VIP fibers and NPY fibers were localized in the deeper parts of dermis around blood vessels and acini of sweat glands. Also fibers containing these neuropeptides were most common in fingertips and toes. VIP occurred in relatively high amounts also in skin from axilla whereas NPY in this region was below detection limit. Immunoreactive somatostatin was found in low concentrations in tissue extracts and was not present in amounts sufficient for reliable immunostaining. Fluid from spontaneous blisters on inflamed skin contained detectable amounts of all neuropeptides.     

Inhibition of neuropeptide degradation suppresses sweating but increases the area of the axon reflex flare

The neuropeptides CGRP (calcitonin gene‐elated peptide) and substance P (SP) mediate neurogenic inflammation. Both are degraded by the neutral endopeptidase (NEP) which can be blocked by phosphoramidon. The aim was to evaluate the effect of NEP inhibition on sweating and vasodilatation. Dermal microdialysis was performed on the skin of 39 subjects. Two fibres were perfused with phosphoramidon (0.01%, 0.02% or 0.2%), two with saline. Acetylcholine (ACh) was either added to the microdialysis perfusate (n = 30, 10⁻² m ) or thermoregulatory sweating was induced (n = 9). Co‐application of phosphoramidon reduced cholinergic and thermoregulatory sweating. However, the flare size – a localized increase in superficial blood flow after ACh‐application – was significantly increased. The increase in flare size is most probably due to increased CGRP levels. The inhibition of sweating by phosphoramidon may involve an increase in SP, a reduction in CGRP‐degradation fragments or a direct inhibitory action of phosphoramidon.     

Effectiveness of as‐needed antihistamines in chronic spontaneous urticaria patients under omalizumab treatment

The question how second‐generation antihistamines (sgAHs) should be used when chronic spontaneous urticaria (CSU) is under control with omalizumab is still unanswered. This study aimed to investigate the effectiveness of as‐needed sgAHs in patients with well‐controlled urticaria under omalizumab treatment. Patients from four different urticaria centers who were treated with omalizumab 300 mg/4 weeks for at least 3 months, had well‐controlled urticaria (Urticaria Control Test: 16 > UCT≥12) and were using sgAHs only if needed, were included in this study. In order to assess effectiveness of sgAHs, change in the itch, hives, and total itch‐hives scores before and after sgAHs were evaluated using modified urticaria activity score‐twice daily. Fifty‐three patients [38 female (71.7%)] with mean age 41.1 ± 11.4 years were included in this study. Median sgAH intake per patient throughout the 4 week‐intervals was 3 (2–5) tablets. sgAH intake decreased itch, hives and total itch‐hives scores 45.7% ± 52.9, 42.4% ± 39.1, and 50.2% ± 51.1, respectively (P < .001 for all). This decrease was similar in both isolated‐urticaria and urticaria‐and‐angioedema phenotypes. Baseline IgE levels were positively correlated with the decrease of three symptom scores (r = 0.31, P = .05; r = 0.375, P = .017; r = 0.31, P = .05, respectively) that showed in patients with higher baseline total IgE levels, as needed sgAH intake decreased the symptom scores less. Our study showed that sgAHs may still be an effective option for the treatment of the intermittent symptoms in patients with well‐controlled urticaria under omalizumab treatment. Baseline total IgE levels may be used as a potential biomarker for sgAH effectiveness in these patients.     

NERVE GROWTH FACTOR, NEUROPEPTIDES AND CUTANEOUS NERVES IN ATOPIC DERMATITIS

Introduction:

Neurogenic components, as neurotrophic factors and neuropeptides, are probably involved in the pathogenesis of atopic dermatitis (AD) with the neuroimmunocutaneous system as they modify the functions of immunoactive cells in the skin. Nerve growth factor (NGF) is the best-characterized member of the neurotrophin family. Both NGF and neuropeptides (NPs) may be associated with the disease pathogenesis.

Aim:

This study aims to evaluate the plasma level of NGF and NPs in AD patients and correlate them with the disease activity and nerve changes in the skin by electron microscopy.

Materials and Methods:

Plasma levels of NGF and vasoactive intestinal peptide (+VIP) were measured by an immunoenzymatic assay while plasma levels of calcitonine gene related peptide (CGRP) and neuropeptide Y (NPY) were measured by radioimmunoassay in 30 AD patients in comparison to 10 normal non-atopic controls. Electron microscopic study was done in 10 AD patients.

Results:

It has been found that there is significant increase of plasma levels of NGF and NPs in AD patients compared with controls. There is a positive correlation between the plasma levels of NGF and disease activity (correlation coefficient = 0.750, P<0.005). There is a significant correlation between the number of Schwann axon complex, evidenced by electron microscopic examination and plasma level of NGF in AD patients.

Conclusion:

It has been concluded that these neurogenic factors; NGF and NPs modulate the allergic response in AD, probably through interactions with cells of the immune-inflammatory component. NGF might be considered as a marker of the disease activity.     

Therapy of acute and chronic urticaria

Background The drug management of chronic urticaria can be divided into three approaches: (i) blockade of released histamine at the receptor sites; (ii) blockade of histamine release from mast cells; and (iii) blockade of other mediators and possible inflammatory and cellular components. The first approach is the most successful and widely used. It primarily involves the use of H₁-antihistamines, although tricyclic antidepressants and H₂-antihistamines also have a place. Treatments The usefulness of classic H₁-antihistamines, such as hydroxyzine, may be limited by side-effects (most notably, sedation). The four most widely used of the newer antihistamines are loratadine, terfenadine, astemizole and cetirizine. These antihistamines are significantly superior to placebo and have similar efficacies comparable with hydroxyzine. Novel agents and methods, including nifedipine, sulphasalazine and plasmapheresis have been tried with some success in refractory patients. Guidelines If acute cases are inadequately controlled, short-term oral corticosteroids may be added. Systemic corticosteroids are occasionally indicated for the management of severe acute urticaria, severe serum sickness, pressure urticaria or urticarial vasculitis, or to break the cycle of a resistant case, but have no place in regular therapy for chronic urticaria. For those with severe acute urticaria with signs of respiratory distress, possible treatments include subcutaneous epinephrine, systemic corticosteroids and intramuscular H₁-antihistamines. Patients with chronic urticaria inadequately controlled on H₁-antihistamines alone may benefit from the addition of a classic antihistamine, a tricyclic antidepressant or an H₂-antihistamine. A short course of systemic corticosteroids may help those with severe chronic refractory disease.     

Serum substance P and calcitonin gene-related peptide levels in Behçet's disease and their association with disease activity

Background. Substance P (SP) and calcitonin gene‐related peptide (CGRP) are neuropeptides that have a role in several cutaneous diseases and inflammations. Aim. To evaluate SP, CGRP and serum interleukin (IL)‐8 levels in Behçet's disease (BD) and to explore the relationship of these peptides with BD activity. Methods. The study group comprised 30 patients with BD, and 30 healthy individuals acted as controls. Serum levels of SP, CGRP and IL‐8 were determined by micro‐ELISA test during the active and inactive disease periods of patients with BD. These data were compared with each other and controls. Active and inactive periods of BD were established. Results. The mean ± SD serum CGRP (ng/ml) and IL‐8 levels (pg/ml) in inactive BD (5.87 ± 2.49 and 0.62 ± 0.24, respectively) were significantly higher than the control group (4.74 ± 1.17 and 0.46 ± 0.11) (P < 0.05 for both). The difference between serum CGRP and IL‐8 levels in active BD were also significantly higher than in inactive BD (P < 0.05 for both). Serum SP values (ng/ml) in active BD (18.27 ± 5.38) were significantly higher than in inactive BD (15.26 ± 5.74) and controls (12.6 ± 4.45) (P < 0.05 for all), whereas the difference between the serum SP values in inactive BD and the control group was not statistically significant (P > 0.05). Conclusion. Serum SP and CGRP may have a role in the pathogenesis of BD. In addition, serum IL‐8, SP and CGRP levels can be used as laboratory parameters indicating activity in BD.     

Methotrexate: a useful steroid-sparing agent in recalcitrant chronic urticaria

Background Reports of methotrexate for chronic urticaria are anecdotal. Objectives To assess the effectiveness of methotrexate in steroid‐dependent chronic urticaria, its impact on steroid reduction and any differences in response between patients with and without functional autoantibodies. Methods A retrospective case‐note review of 16 patients with steroid‐dependent chronic urticaria treated with methotrexate was carried out. Ten patients had chronic ordinary/spontaneous urticaria (CU), including three with associated delayed‐pressure urticaria; four patients had normocomplementaemic urticarial vasculitis (UV); and two patients had idiopathic angio‐oedema without weals. Median disease duration before methotrexate was 48·5 months (range 12–164). All were unresponsive to antihistamines and second‐line agents, except prednisolone. Eleven were assessed for autoimmune urticaria with the basophil histamine release assay (n = 5), autologous serum skin test (n = 5) or both (n = 1). Response to methotrexate was scored: no benefit; some benefit (fewer weals and symptomatic improvement but no steroid reduction); considerable benefit (improvement with steroid reduction); or clear (no symptoms, off steroids but on antihistamines). Results Twelve of 16 patients (eight CU, three UV, one idiopathic angio‐oedema) responded. Three showed some benefit, seven considerable benefit and two cleared. Four of eight responders and three out of three nonresponders showed evidence of functional autoantibodies. The dose to achieve a steroid‐sparing effect was 10–15 mg weekly (cumulative dose range 15–600 mg, median 135 mg). Methotrexate was well tolerated. Conclusions Methotrexate may be a useful treatment for steroid‐dependent chronic urticaria. Functional autoantibodies do not correlate with response. The beneficial effects of methotrexate may be anti‐inflammatory and immunosuppressive. It may therefore benefit chronic urticaria independently of the pathogenic mechanism, whether autoimmune or not.     

US Prescription trends of antihistamines for atopic dermatitis, 2011‐2016

Antihistamine use for primary treatment of atopic dermatitis (AD) is not recommended, but current guidelines state that sedating antihistamines are favored over non‐sedating antihistamines for relief of burdensome pruritus. We analyzed the National Ambulatory Medical Care Survey data to compare use of antihistamines between dermatologists and non‐dermatologists. Overall, dermatologists are more likely to prescribe sedating than non‐sedating antihistamines when compared to non‐dermatologists (P < .001, δ_abs = 0.45). Patients under 21 years old (P = .03, δ_abs = 0.10) and Black patients (P < .001, δ_abs = 0.19) were also more likely to receive sedating antihistamines than non‐sedating antihistamines. These findings highlight the differential prescribing practices for atopic dermatitis among physicians.