Cholinergic Urticaria: Subtype Classification and Clinical Approach

Skin reaction patterns in cholinergic urticaria

BACKGROUND

Skin reaction patterns vary across patients with cholinergic urticaria (CholU), but their definition, prevalence, and clinical significance remain ill characterized.

METHODS

Patients with CholU underwent pulse-controlled ergometry provocation testing to analyze skin reaction patterns and their correlation with location, onset, severity, sweating behaviour, clinical features, disease control, and quality of life (QoL) impairment.

RESULTS

Based on the size, color, spacing, and shape of wheals as well as their surrounding skin responses, we identified six distinct types of CholU skin reactions, which differed in prevalence, from 83% (Type I) to 11% (Type VI) of patients affected. Almost all patients (94%) had ≥1 type of skin reaction pattern. Sweating was reduced in the majority of CholU patients and most prominently reduced in patients with Type VI skin signs (very small, round, red, widely spaced wheals with surrounding anemic halo), which emerged exclusively on the extremities. Type V skin signs (large, irregular, anemic, widely spaced wheals with moderate size erythema) were associated with the most severe clinical presentation and poorest QoL.

CONCLUSIONS

Our analysis showed that most patients have more than one type of skin reaction patterns and that different skin signs are linked to distinct features. Future studies should determine any links between treatment response and types of skin signs in CholU.

Allergic Diseases and Mental Health

Neuropsychiatric symptoms have long been acknowledged as a common comorbidity for individuals with allergic diseases. The proposed mechanisms for this relationship vary by disease and patient population and may include neuroinflammation and/or the consequent social implications of disease symptoms and management. We review connections between mental health and allergic rhinitis, atopic dermatitis, asthma, vocal cord dysfunction, urticaria, and food allergy. Many uncertainties remain and warrant further research, particularly with regard to how medications interact with pathophysiologic mechanisms of allergic disease in the neuroimmune axis. Proactive screening for mental health challenges, using tools such as the Patient Health Questionnaire and Generalized Anxiety Disorder screening instruments among others, can aid clinicians in identifying patients who may need further psychiatric evaluation and support. Although convenient, symptom screening tools are limited by variable sensitivity and specificity and therefore require healthcare professionals to remain vigilant for other mental health "red flags." Ultimately, understanding the connection between allergic disease and mental health empowers clinicians to both anticipate and serve the diverse physical and mental health needs of their patient populations.

Chronic Inducible Urticaria

Chronic inducible urticaria (CIndU) is characterized by the appearance of hives (urticaria) and/or angioedema in response to specific triggers or stimuli. For accurate diagnosis, anamnesis-driven specific, and if available, standardized trigger testings, as well as patient reported outcomes, should be applied. The currently recommended treatment algorithm is the same as for chronic spontaneous urticaria but is largely off-label for CIndU. New, and possibly more disease-specific, treatment options are needed for CIndU patients, who are often severely impacted by their disease. Several clinical trials are currently ongoing.

New insights into chronic inducible urticaria

PURPOSE OF REVIEW

Chronic inducible urticaria (CIndU) is a group of long-persisting and challenging to manage diseases, characterized by recurrent wheals and angioedema induced by definite triggers. In this review, we address recent findings on CIndU pathogenesis, diagnosis as well as its treatment, and we discuss novel potential targets that may lead to the development of more effective therapies for CIndU patients.

RECENT ADVANCES

Meaningful advances in the understanding of its pathogenesis have been reported in the last decades. Novel CIndU-specific patient-reported outcome measures enable a closer and better evaluation of patients. CIndU is a hard-to-treat disease that highly impairs quality of life (QoL) of affected patients. Provocation tests allow to diagnose CIndU subtypes. The only licensed and recommended treatment for CIndU are second generation non-sedating H1-antihistamines, which lack efficacy in many cases. Omalizumab off-label use has been assessed in all types of CIndU with overall good outcomes. Promising emerging therapies currently assessed in chronic spontaneous urticaria are paving the path for novel treatments for CIndU.

Efficacy, safety, and serum cytokine modulation by olopatadine hydrochloride and desloratadine citrate disodium combination therapy in urticaria

OBJECTIVES

To assess the efficacy, safety, and impact on serum cytokines of olopatadine hydrochloride (OLP) combined with desloratadine citrate disodium (DES) in treating urticaria.

METHODS

We retrospectively analyzed 114 urticaria patients treated at the Affiliated Hospital of Xinyang Vocational and Technical College from March 2020 to March 2023. The control group (55 patients) received DES, while the research group (59 patients) received OLP+DES combination therapy. We compared efficacy, safety (including epigastric pain, dry mouth, lethargy, dizziness, and fatigue), changes in serum cytokines (interleukin [IL]-2, IL-4, and interferon [IFN]-γ), symptom resolution (wheal number, wheal size, and itching degree), and 3-month recurrence rates. A univariate analysis was also conducted to identify factors influencing urticaria recurrence.

RESULTS

The research group exhibited a significantly higher overall efficacy rate, lower incidence of adverse events, and reduced recurrence rates at 3 months (all P<0.05) compared to the control group. Post-treatment, the research group showed significant increases in IL-2 and IFN-γ levels and reductions in IL-4 levels, wheal number, wheal size, and itching degree (all P<0.05). Factors such as history of drinking/smoking, IL-2 levels, and treatment method were associated with urticaria recurrence (all P<0.05).

CONCLUSIONS

The combination of OLP and DES is an effective and safe treatment option for urticaria, significantly improving serum cytokine profiles, alleviating symptoms, and reducing recurrence risk.

Targeting histamine receptor 4 in cholinergic urticaria with izuforant (LEO 152020): results from a phase IIa randomized double-blind placebo-controlled multicentre crossover trial

BACKGROUND

Cholinergic urticaria (CholU) is a common subtype of chronic inducible urticaria, where signs and symptoms (e.g. pruritic wheals and angioedema) are triggered by sweating due to physical exercise, passive warming and by other sweat-inducing situations. While guidelines recommend treatment with second-generation H1 antihistamines, approximately 90% of patients report uncontrolled disease. Targeting the histamine 4 receptor (H4R) has shown promise in preclinical/clinical studies of allergic/inflammatory diseases. Izuforant (LEO 152020) is a selective oral H4R antagonist with expected dual antipruritic and anti-inflammatory effects.

OBJECTIVES

To assess the effects of izuforant in adults with CholU, a common type of chronic urticaria driven by histamine and characterized by high skin levels of H4R expression.

METHODS

This was a phase IIa randomized double-blind placebo-controlled multicentre crossover trial where patients with CholU with an inadequate response to ≥ 1 standard dose of H1 antihistamine received izuforant 100 mg twice daily or placebo (EUCTR2020-004961-38-DE; NCT04853992). The primary endpoint was change from baseline in Urticaria Activity Score. Exploratory endpoints included CholU activity score over 7 days, urticaria control test, Physician Global Assessment, patient global assessment of severity (PGA-S), provocation tests, Dermatology Life Quality Index and CholU quality of life (CholU-QoL). Pharmacokinetic and pharmacodynamic parameters, and serum biomarkers were assessed, as well as safety and tolerability.

RESULTS

Nineteen patients were randomized and included in the full analysis set; 18 completed treatment [mean (SD) age 29.5 (9.8) years; mean (SD) CholU duration 8.0 (6.3) years]. The primary and most of prespecified exploratory endpoints were not met; there were significant improvements in PGA-S for izuforant vs. placebo (P = 0.02), and nonsignificant improvements for other endpoints in quality of life and histamine skin prick test. All adverse events (AEs) experienced with izuforant were considered mild. The most frequently reported (> 1 patient) were nausea (three patients) and upper abdominal pain (two patients), occurring more frequently with izuforant vs. placebo (one patient each). There were no treatment-related serious AEs and no patient receiving izuforant discontinued the study. Treatment with izuforant did not cause downregulation of H4R.

CONCLUSIONS

This is the first study to explore the role of H4R as a therapeutic target in urticaria. Targeting H4R with izuforant was well tolerated but did not demonstrate significant improvements vs. placebo in the primary endpoint and all but one prespecified exploratory endpoint in CholU.

Clozapine-induced cholinergic urticaria: a case report

Clozapine, renowned for its efficacy in treatment-resistant schizophrenia, is associated with rare yet potentially severe side effects, including hematological disorders, myocarditis, seizures and gastrointestinal obstruction. Dermatological adverse effects, though less serious, can profoundly impact patients' quality of life. We present the first reported case of cholinergic urticaria induced by clozapine, in a 25-year-old male with treatment-resistant schizophrenia. Four months into clozapine therapy, the patient developed intensely pruritic erythematous lesions triggered by sweating, significantly impairing his daily activities. Despite attempts at management, including dose reduction and antihistamine therapy, the urticaria persisted. However, a favorable outcome was achieved upon switching to quetiapine. This case underscores the importance of recognizing and managing treatment-related adverse effects, even when they arise late in treatment, and highlights the need for individualized therapeutic approaches.We discuss potential mechanisms underlying clozapine-induced cholinergic urticaria and emphasize the significance of patient-centered care in optimizing treatment outcomes in schizophrenia.

Altered Sweat Composition Due to Changes in Tight Junction Expression of Sweat Glands in Cholinergic Urticaria Patients

In cholinergic urticaria (CholU), small, itchy wheals are induced by exercise or passive warming and reduced sweating has been reported. Despite the described reduced muscarinic receptor expression, sweat duct obstruction, or sweat allergy, the underlying pathomechanisms are not well understood. To gain further insights, we collected skin biopsies before and after pulse-controlled ergometry and sweat after sauna provocation from CholU patients as well as healthy controls. CholU patients displayed partially severely reduced local sweating, yet total sweat volume was unaltered. However, sweat electrolyte composition was altered, with increased K+ concentration in CholU patients. Formalin-fixed, paraffin-embedded biopsies were stained to explore sweat leakage and tight junction protein expression. Dermcidin staining was not found outside the sweat glands. In the secretory coils of sweat glands, the distribution of claudin-3 and -10b as well as occludin was altered, but the zonula occludens-1 location was unchanged. In all, dermcidin and tight junction protein staining suggests an intact barrier with reduced sweat production capability in CholU patients. For future studies, an ex vivo skin model for quantification of sweat secretion was established, in which sweat secretion could be pharmacologically stimulated or blocked. This ex vivo model will be used to further investigate sweat gland function in CholU patients and decipher the underlying pathomechanism(s).

The many faces of pediatric urticaria

Urticaria is a common disease that can affect individuals of all age groups, with approximately one-quarter of the population experiencing it at least once in their lifetime. Lesions characterized by erythema and itchy hives can appear anywhere on the body. These can vary in size ranging from millimeters to centimeters, and typically clear within 24 h. About 40% of patients with urticaria have accompanying angioedema, which involves localized deep tissue swelling. Urticaria usually occurs spontaneously and is classified into acute and chronic forms, with the latter referring to a condition that lasts for more than 6 weeks. The prevalence of chronic urticaria in the general population ranges from 0.5% to 5%, and it can either be inducible or spontaneous. The most common form of pediatric urticaria is acute and is usually self-limiting. However, a broad differential diagnosis should be considered in children with urticaria, particularly if they also have accompanying systemic complaints. Differential diagnoses of pediatric urticaria include chronic spontaneous urticaria, chronic inducible urticaria, serum sickness-like reaction, urticarial vasculitis, and mast cell disorders. Conditions that can mimic urticaria, including but not limited to cryopyrinopathies, hyper IgD syndrome, Periodic Fever, Aphthous Stomatitis, Pharyngitis and Adenitis (PFAPA), Tumor Necrosis Factor Receptor Associated Periodic Syndrome (TRAPs), and Schnitzler syndrome should also be considered. The many faces of pediatric urticaria can be both easy and confusing. A pragmatic approach relies on clinical foresight and understanding the various forms of urticaria and their potential mimickers. This approach can pave the way for an accurate and optimized diagnostic approach in children with urticaria.

General anesthetic management in two patients with an anaphylaxis history cholinergic urticaria

BACKGROUND

Cholinergic urticaria is triggered by an increased body temperature after exercise, passive warming, or emotional stresses. The anesthetic management used for two patients with an anaphylaxis history after cholinergic urticaria is described.

CASE PRESENTATION

Patient 1: A 34-year-old female was scheduled for a right-side thyroidectomy. At 27 years old, she experienced post-exercise anaphylaxis and repeated episodes of hives following exercise, sunbathing, mental stresses, and the consumption of spicy foods. Patient 2: A 35-year-old female was scheduled for a laparoscopic ovarian cystectomy. At 19 years old, she experienced anaphylaxis after a long bath and then hives after hot showers, bicycle riding, and long walks. For both patients, intraoperative passive warming was not performed to prevent excessive warming, and prophylactic antiemetics and multimodal analgesia were used to minimize their perioperative stresses.

CONCLUSION

Careful anesthetic management is necessary to prevent anaphylaxis during anesthesia in a patient with a history of cholinergic urticaria.

A single-blind, randomized, crossover study on the efficacy of icatibant for sweating-induced dermal pain (icatibant for sweating-induced dermal pain)

INTRODUCTION

Severe dermal pain triggered by sweating stimuli, such as bathing, exercise, and mental stress, significantly affects patients' daily lives. The pathomechanism underlying the sweating-induced dermal pain remains poorly understood and there exists no standard treatment for such pain. This study aims to evaluate the effectiveness of icatibant as an analgesic, a bradykinin B2 receptor antagonist, in treating sweating-induced dermal pain, and to establish the role of bradykinin in pain induction.

METHODS/DESIGN

A multicenter, exploratory, crossover, single-blinded, placebo-controlled randomized, comparative study will be conducted to evaluate the efficacy of subcutaneous icatibant injection (30 mg) in treating sweating-induced dermal pain. Ten patients will be enrolled and assigned randomly in a 1:1 ratio to either the icatibant-placebo or placebo-icatibant groups. The primary endpoint is the change in the visual analog scale scores for dermal pain induced by thermal load before and after treatment with icatibant or placebo. Secondary endpoints include changes in the duration of dermal pain, blood and plasma histamine levels, serum angiotensin-converting enzyme levels, and histological evaluation of skin tissue samples at the site of dermal pain.

DISCUSSION

The effectiveness of icatibant against sweating-induced dermal pain would provide clear evidence for the involvement of the bradykinin-bradykinin B2 receptor pathway in the pathogenesis of this condition. This finding may contribute to a better understanding of the underlying mechanisms of dermal pain associated with sweating stimuli and has the potential to improve patients' quality of life by suggesting potential treatment options, specifically, using drugs that inhibit bradykinin or suppress its production.