Pathogenesis of cholinergic urticaria in relation to sweating

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.

Case Report: Hives and faints, an unusual affair

Cholinergic urticaria (CholU) is a rare condition characterized by itchy hives in the form of 1-4 mm small, raised wheals on skin, which are short-lived for duration of 15 to 20 minutes; they are caused by stimuli associated with sweating such as from physical exercise. CholU is also known as cholinergic angioedema urticaria. Hereby, we present a case report of a 42-year-old male with ChoIU who presented with systemic manifestation in the form of recurrent attacks of syncope. Diagnosis was made after a detailed history taking and all cardiac and neurological evaluations done that were normal, and widespread literature research was done to rule out other causes of syncope as systemic symptoms are rarely seen in ChoIU. His IgE antibodies levels were highly increased. He was managed with nonsedating antihistamines and health education regarding the rare condition.

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.

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.

Cholinergic Urticaria: Subtype Classification and Clinical Approach

Cholinergic urticaria (CholU) is a subtype of chronic inducible urticaria with a chief complaint of itching and/or stinging, painful papular wheals that develop simultaneously with sweating. This review specifically focuses on several subtypes of CholU and specifically investigates the relationship between CholU and anhidrosis. We review recent publications and update the evidence around CholU, including the epidemiology, clinical features, diagnostic approaches, physiopathology, subtype classification, and therapeutic approaches. Multiple mechanisms contribute in a complex manner to the development of CholU, including histamine, sweat allergy, cholinergic-related substances, poral occlusion, and hypohidrosis/anhidrosis. A new schematic of the currently known pathological conditions has been created. Specific methods for diagnosing CholU, a provocation test, and evaluation methods for disease severity/activity and disease burden of CholU are summarized. The characteristics of the diseases that should be differentiated from CholU and examination methods are also summarized. The primary finding of this review is that CholU should be categorized based on the etiology and clinical characteristics of each subtype to properly manage and treat the disease. This categorization leads to improvement of therapeutic resistance status of this disease. In particular, a sweating abnormality should be given more attention when examining patients with CholU. Because CholU is not a homogeneous disease, its subtype classification is important for selection of the most suitable therapeutic method. Further elucidation of the pathophysiology of each subtype is expected.

Impaired sweating in patients with cholinergic urticaria is linked to low expression of acetylcholine receptor CHRM3 and acetylcholine esterase in sweat glands

Background

Cholinergic urticaria (CholU), a frequent form of chronic inducible urticaria, is characterized by itchy wheals and angioedema in response to sweating. As of now, the rate and pathophysiological relevance of impaired sweating in patients with CholU are ill-defined.

Aim

To assess in CholU patients the rate and extent of impaired sweating and its links to clinical and pathophysiological features of CholU.

Patients and methods

We assessed sweating in patients with CholU (n = 13) subjected to pulse-controlled ergometry (PCE) provocation testing. Pre- and post-PCE biopsies of lesional (L) and non-lesional (NL) skin were analyzed for the expression of acetylcholine receptor M3 (CHRM3) and acetylcholine esterase (ACh-E) by quantitative histomorphometry and compared to those of healthy control subjects (HCs). CholU patients were assessed for disease duration and severity as well as other clinical features.

Results

Of the 13 patients with CholU, 10 showed reduced sweating in response to PCE provocation, and 3 had severely reduced sweating. Reduced sweating was linked to long disease duration and high disease severity. CholU patients with impaired sweating responses showed reduced sweat gland epithelial expression of CHRM3 and ACh-E.

Conclusion

Reduced sweating is common in CholU patients, especially in those with long-standing and severe disease, and it can be severe. Reduced expression of CHRM3 and ACh-E may be the cause or consequence of CholU in patients with impaired sweating, and this should be explored by further studies.

Acetylcholine-induced whealing in cholinergic urticaria - What does it tell us?

BACKGROUND

Cholinergic urticaria (CholU) is characterized by the occurrence of itchy wheals induced by sweating. Intradermal injections of acetylcholine (ACh) have been proposed to help with diagnosing CholU and subgrouping of patients, but controlled studies are largely missing.

OBJECTIVE

To compare the rates of positive ACh test results in well characterized CholU patients and controls and to identify clinical features of CholU linked to ACh reactivity.

METHODS

Acetylcholine was injected intradermally into 38 CholU patients and 73 matched healthy controls. Wheal and flare skin responses were assessed after 15 and 30 min and correlated with clinical features of CholU.

RESULTS

At 15 min after intradermal injections of ACh, wheal and flare responses were significantly more frequent in CholU patients than healthy controls, wheals: 34 % vs.15% (P = 0.028); flares: 50 % vs.18 % (P <0.001). Also, wheals were 37 % and flares 172 % larger and of longer duration in CholU patients than in healthy controls (both P < 0.01). CholU patients with ACh-induced wheals (ACh⁺) had larger flare but not wheal responses in response to histamine than those without (ACh^-; P = 0.011). Also, ACh-induced wheal responses were significantly correlated with sweating (r = 0.54, P = 0.046) in CholU patients. Finally, wheal responses lasted longer in ACh⁺ than in ACh^- patients (P = 0.03).

CONCLUSION

Intradermal ACh testing does not allow for the identification of CholU patients due to its low sensitivity. ACh-induced wheals, in patients with CholU, is linked to sweating and longer lasting symptoms. Intradermal ACh testing is an interesting tool for mechanistic studies in CholU.

Direct and indirect action modes of acetylcholine in cholinergic urticaria

Cholinergic urticaria (CholU) manifests small, itchy and/or painful wheals occurring upon perspiration and mechanically involving acetylcholine (Ach). Although a considerable number of studies have been conducted, the pathomechanisms underlying perspiration-associated release of histamine remain to be elucidated. We have proposed that CholU can be categorized into two major subtypes: Ach-indirectly induced, sweat allergic type and Ach-directly induced, depressed sweating type. In the former type, Ach evokes perspiration, and some sweat antigen(s) leaking from the sweat ducts to the dermis may stimulate mast cells to release histamine. In this scenario, the ducts might be damaged or obstructed for sweat leakage, and patients frequently exhibit positive autologous sweat skin test, representing "sweat allergy (hypersensitivity)". On the other hand, the latter Ach-mast cell directly interacting type, typically seen as "CholU with anhidrosis and/or hypohidrosis (CUAH)", eccrine sweat gland epithelial cells lack cholinergic receptor M3 expression. The expression of cholinergic receptors is completely absent in the anhidrotic areas and only slightly expressed in the hypohidrotic areas. In the hypohidrotic area, where pinpoint wheal occurs, it is hypothesized that released Ach cannot be completely trapped by cholinergic receptors of eccrine glands and overflows to the adjacent mast cells, leading to wheal formation. Thus, sweat allergy is not a requirement in this depressed sweating type. Although some additional complications, such as angioedema, anaphylaxis, and cold urticaria, have been documented, these two types represent the modes of action of Ach in this enigmatic urticaria.

Cholinergic Urticaria: Clinical Presentation and Natural History in a Tropical Country

BACKGROUND

Cholinergic urticaria (CholU) is a subset of chronic inducible urticaria characterized by the recurrent pinpoint-sized wheals that are induced by exercising or increasing core body temperature. Currently, the data of CholU in tropical climate is still limited.

OBJECTIVE

To investigate the clinical features and natural course of CholU in a tropical country.

MATERIALS AND METHODS

This retrospective chart review study analyzed the data of CholU patients aged over 18 years who visited Siriraj Urticaria Clinic, Siriraj Hospital, Bangkok, Thailand, between January 2007 and September 2019. Demographic data, clinical presentations, and results of provocation tests and other laboratory investigations were evaluated and compared with other studies reported in temperate zones.

RESULTS

Sixteen out of 2,175 chronic urticaria patients (0.7%) were diagnosed with CholU. The median age of CholU patients was 28.0 ± 11.7 years with male predominance (56.3%). Three patients (18.8%) had a history of atopy. Fifteen patients (93.8%) were positive to the exercise provocation test. Nonsedating antihistamine drugs were a main treatment (73.8%). Six patients (37.5%) were in remission at the time of the study, with a mean duration 4.3 years. The Kaplan-Meier survival analysis demonstrated that 12.5%, 35.5%, and 67.9% of patients would have disease remission within 1 year, 5 years, and 13 years, respectively.

CONCLUSIONS

The prevalence of CholU differs in each geographic region and is found to be low in tropical countries with a median duration 4.3 years. The prevalence of atopy and anaphylaxis with CholU is also lower in tropical countries than in temperate.

Sensitization against skin resident fungi is associated with atopy in cholinergic urticaria patients

Background

Cholinergic urticaria (CholU) is a common type of chronic inducible urticaria, characterized by small itchy wheals that appear upon physical exercise or passive warming. Malassezia globosa, a skin resident fungus, has been identified as an antigen that induces mast cell/basophil degranulation and wheal formation through specific IgE, in Japanese patients with atopic dermatitis and CholU. In this study we aimed in assessing the rate of IgE sensitizations against skin resident fungi in European CholU patients.

Methods

We assessed serum IgE levels to Malassezia furfur, Candida albicans and Trichophyton mentagrophytes using routine lab testing and Malassezia globosa using a newly established ELISA. We correlated the results to wheal formation and other clinical features.

Results

Four patients (of 30 tested) had elevated levels of IgE against Malassezia furfur and Candida albicans and two had elevated levels of IgE against Trichophyton mentagrophytes. Four sera (of 25 tested) had elevated levels of IgE to the Malassezia globosa antigen supMGL_1304. Sensitization to one skin fungus was highly correlated with sensitization to the other tested fungi. We saw highly significant correlations of sensitization to supMGL_1304 with wheal size in the autologous sweat skin test (r_s = 0.7, P = 0.002, n = 19), the Erlangen atopy score (r_s = 0.5, P = 0.03, n = 19), total IgE serum levels (r_s = 0.5, P = 0.04, n = 19) and a positive screen for IgE against common airborne/inhalant allergens s (sx1; r_s = 0.54, P = 0.02, n = 19).

Conclusions

Sensitization to skin resident fungi including Malassezia globosa is uncommon in European CholU patients, but is associated with atopy and pronounced wheal formation upon dermal contact with their own sweat.

Trial registration German Clinical Trials Registry DRKS-ID: DRKS00004277

Cholinergic urticaria: epidemiology, physiopathology, new categorization, and management

PURPOSE

The aim of this study was to review the evidence on the epidemiology, physiopathology, categorization, and management of cholinergic urticaria. We specifically focused on several subtypes of cholinergic urticaria and investigated the relationship between cholinergic urticaria and idiopathic anhidrosis.

METHODS

Using an integrative approach, we reviewed publications addressing the epidemiology, clinical features, diagnostic approach, physiopathology, subtype classification, and therapeutic approach to cholinergic urticaria.

RESULTS

Multiple mechanisms were found to contribute to the development of cholinergic urticaria. This disorder should be classified based on the pathogenesis and clinical characteristics of each subtype. Such a classification system would lead to better management of this resistant condition. In particular, sweating function should be given more attention when examining patients with cholinergic urticaria.

CONCLUSIONS

Because cholinergic urticaria is not a homogeneous disease, its subtype classification is essential for selection of the most suitable therapeutic method.

Neuroethology as a translational neuroscience strategy in the era of the NIMH Research Domain Criteria

The article by Latzman et al. in the current special issue utilizes a novel dataset consisting of behavioral, brain, and genomic data from a sample of 76 captive chimpanzees to make the case that negative affective expression is influenced by variation in the gene coding for arginine vasopressin receptor 1A (AVPR1A), in a sex-linked manner. A novel feature of this study is the ethological approach employed by the authors, i.e., the use of scratching as a behavioral indicator of negative affective state. I comment on conceptual and methodological aspects of this work, and consider how it interfaces with the Research Domain Criteria (RDoC) framework as described by Kozak and Cuthbert in their article for this issue.

Atopic predisposition in cholinergic urticaria patients and its implications

BACKGROUND

Cholinergic urticaria (CholU) is a frequent chronic urticaria disorder with itchy weal and flare-type skin reactions in response to physical exercise or passive warming. A higher frequency of atopy among CholU patients has been reported, but the significance of this observation is unclear.

OBJECTIVE

To assess the prevalence and relevance of atopy in CholU patients.

MATERIALS AND METHODS

Thirty CholU patients were assessed for atopic skin diathesis (atopic predisposition) by use of the Erlangen Atopy Score and divided into atopic and non-atopic predisposed CholU individuals. Both groups were assessed for disease severity (CholUSI) and activity (CholUAS7), quality of life impairment [Dermatology Life Quality Index (DLQI) and CU-Q₂ OL], seasonal exacerbation, total and specific serum IgE and comorbidities.

RESULTS

CholU patients were found to exhibit high rates of atopic predisposition (57%), with higher prevalence and scores in female than in male patients. High Erlangen Atopy Scores were linked to high CholU severity, activity and impact on QoL. Atopic predisposed CholU patients show different seasonal exacerbation patterns, IgE specificity and comorbidity profiles as compared to non-atopic CholU patients.

CONCLUSION

Atopic predisposition and cholinergic urticaria appear to be linked more closely than previously thought, which suggests shared pathogenetic mechanisms. Atopic patients with cholinergic urticaria have more severe disease and poorer quality of life than those who do not. Thus, all cholinergic urticaria patients should be assessed for atopic predisposition.

Cholinergic urticaria: More than a simple inducible urticaria

BACKGROUND

Cholinergic urticaria (ChU) is characterized by small wheals induced by an elevated core temperature. Its pathomechanism and various aspects of its clinical manifestations are still poorly understood. This study aimed to evaluate the spectrum of symptoms and signs of ChU in Korean patients.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with ChU.

RESULTS

Among 203 patients (188 male and 15 female), 29 (14%) complained only of an itching or burning sensation without visible skin eruption. The prevalence of ChU was highest in patients in their twenties (56%), while most patients first developed their symptoms during their teens (65%). Patients with a visible skin eruption showed better responses to antihistamines than those without skin lesions.

CONCLUSIONS

Physicians should consider the varying manifestations of ChU, including cholinergic pruritus and erythema as minor variants, to provide better management of ChU.

Inducible urticaria: Case series and literature review

Inducible urticaria is a heterogeneous group of skin disorders characterized by the appearance of wheals, pruritus and/or angioedema, sometimes accompanied by systemic symptoms caused by innocuous stimuli (cold, heat, pressure, etc.). This group of disorders compromises people's quality of life and most of the literature in this regard comes from case reports and case series since its epidemiology has been poorly studied and some cases are very rare. The aim of this review is to show an up-to-date overview of the available literature for various types of inducible urticarias, always beginning with an illustrative case and then describing their pathophysiological mechanisms, clinical manifestations, and treatment.

The association of cholinergic and cold-induced urticaria: diagnosis and management

Physical urticaria is often challenging to diagnose and manage. We present a case of both cholinergic and cold-induced urticaria and discuss the diagnosis and management strategies of these two important conditions.

[Inducible urticaria and chronic spontaneous urticaria]

In the recently published 2013 revision of the guidelines of urticaria, chronic urticaria (CU) gathers chronic spontaneous urticaria (CSU) and inducible urticaria (IU), and excludes pseudourticarial rashes with more than 24h-lasting rash or more than 72h-lasting angiœdema. Activity and psychosocial impact of the disease must be measured with validated scores such as Urticaria and Angioedema Activity Scores, Urticaria Control Test, CU-Q2OL, AE-QOL. Although an allergic cause is generaly absent in CU, pathomecanisms remain elusive even since the well-known role of mast cell degranulation and the presence of autoantibodies anti-FcRεI or anti-IgE. Coagulation pathways may be involved, at least as an amplifying phenomenon. Mean duration of CU is 1 to 4 years, but many patients still have symptoms after 10 years, some predictive factors being known as severity, angioedema, a positive autologous serum test, inducible urticaria. Recommended routine diagnosic tests are validated provocation tests for IU (and cryoproteins for cold urticaria), blood cell count and CRP for CSU, since a thorough history and a normal detailed physical examination should avoid unnecessary tests. Management of CU has been improved by the off-label use of increased dosages of second generation anti- H1 antihistamines, but a subsequent therapeutic intensification may be necessary in some cases. Educational program may prevent this intensification. Independent studies evaluating available molecules are needed, along with more fundamental research studies.

Elevated serum IgE against MGL_1304 in patients with atopic dermatitis and cholinergic urticaria

BACKGROUND

MGL_1304 secreted by Malassezia globosa is contained in human sweat and induces histamine release from basophils in patients with atopic dermatitis (AD) at a high positive rate. The aims of this study were to establish the enzyme-linked immunosorbent assay (ELISA) measuring specific immunoglobulins against MGL_1304 and to investigate the levels of these immunoglobulins in sera of patients with various allergic diseases.

METHODS

Purified MGL_1304 from human sweat (QRX) and recombinant MGL_1304 (rMGL_1304) were prepared for ELISA. To quantify the amount of MGL_1304-specific immunoglobulins, the standard serum was created by pooling sera of 20 patients with AD whose basophils released histamine in response to QRX. A monoclonal antibody which exhibited the highest neutralizing ability against QRX was established as Smith-2, and used as a capture antibody for the assay of QRX-specific IgE. A total of 156 subjects [normal controls (n = 23), AD (n = 63), cholinergic urticaria (CU) (n = 24), bronchial asthma (n = 32), and allergic rhinitis (n = 14)] were enrolled in this study.

RESULTS

ELISA methods to quantify the specific IgE, IgG and IgG4 against MGL_1304 in sera were successfully established. Levels of QRX-specific IgE in sera of patients with AD and CU were significantly higher than those of normal controls. Moreover, the levels of QRX-specific IgE and rMGL_1304-specific IgE in patients with AD were significantly correlated with their disease severities.

CONCLUSIONS

These ELISA methods to quantify the specific immunoglobulins against MGL_1304 are easy and useful means to assess allergy to MGL_1304. MGL_1304 contained in sweat is an important antigen for patients with AD and CU.