Inducible forms of chronic urticaria are characterized by an early age of onset and a long duration of disease. In addition, cold and cholinergic urticaria have a risk of developing systemic, sometimes life-threatening, reactions. Determining the pathogenetic mechanisms and laboratory and clinical predictors of their development is an open question in the understanding of these diseases. This literature review demonstrates the current known facts that allow the identification of patients with cold and cholinergic urticaria in high-risk groups of anaphylaxis development and, therefore, the possibility to prevent emergency situations and to manage them in time. For cold and cholinergic urticaria, observations of Kounis syndrome–acute coronary syndrome (myocardial infarction or unstable angina) have been described. A series of trials, including the large international multicenter COLD-CE study of anaphylaxis in cold urticaria, have identified early age of urticaria onset, severe clinical symptoms, shortening of the critical temperature threshold, comorbid bronchial asthma, concomitant angioedema, and pruritus of the earlobes as warning signs. No such large-scale studies have been conducted for cholinergic urticaria. Among the few high-risk factors for systemic reactions in cholinergic urticaria described in the literature is the occurrence of angioedema. Thus, it is possible to identify some patients in the high-risk group already at the stage of initial anamnesis collection, and additional data can be collected during the examination. Laboratory biomarkers, clinical predictors, understanding the mechanisms of anaphylaxis by physical triggers or their consequences, and optimal options for pathogenetic therapy are still unresolved issues that require further research. The aim of this review is to provide a content analysis of current knowledge about chronic inducible urticarias in order to increase clinicians’ awareness and, consequently, reduce the risk of urgent conditions associated with them.

Paederus dermatitis is an acute irritant contact dermatitis caused by inadvertent contact with rove beetles of the genus Paederus (Coleoptera: Staphylinidae). The condition may be difficult to recognize in individuals and healthcare professionals from non‑endemic regions because the characteristic skin lesions can mimic other inflammatory, infectious, or vesiculobullous dermatoses. The causative toxin, pederin, is associated predominantly with female beetles and is produced by endosymbiotic bacteria of the genus Pseudomonas. We present a series of cases of Paederus dermatitis observed in Russian physicians working in Nicaragua. Several hours after presumed contact with Paederus beetles, the patients developed burning and mild pruritus followed by erythematous macules and streak‑like lesions. Over the following days, grouped vesicles and non‑tense bullae developed, with subsequent erosions, crusting, and post‑inflammatory hyperpigmentation and hypopigmentation. The diagnoses were established clinically on the basis of the characteristic morphology, exposure history, and epidemiological setting. Conservative treatment resulted in gradual resolution of the inflammatory lesions within approximately 2–3 weeks, with residual post‑inflammatory hyperpigmentation. This case series highlights the diagnostic value of recognizing the characteristic linear and bizarrely configured lesions of Paederus dermatitis, particularly in healthcare professionals working in endemic regions.

Inducible forms of chronic urticaria are characterised by an early age of onset and a long duration of disease. In addition, cold and cholinergic urticaria have a risk of developing systemic, sometimes life-threatening, reactions. Determining the pathogenetic mecha-nisms, laboratory and clinical predictors of their development is an open question in the understanding of these diseases. This literature review demonstrates the current known facts that allow to identify patients with cold and cholinergic urticaria in high-risk groups of anaphylaxis development, and, therefore, the possibility to prevent emergency situ-ations and to manage them in time. For cold and cholinergic urticaria, observations of Kounis syndrome - acute coronary syndrome (myocardial infarction or unstable angina) have been described. A series of trials, including the large international multicentre COLD-CE study of anaphylaxis in cold urticaria, have identified early age of urticaria onset, severe clinical symptoms, shortening of the critical temperature threshold, comorbid bronchial asthma, concomitant angioedema and pruritus of the earlobes as warning signs. No such large-scale studies have been conducted for cholinergic urticaria. Among the few high-risk factors for systemic reactions in cholinergic urticaria described in the literature is the occurrence of angioedema. Thus, it is possible to identify a part of patients in the high-risk group already at the stage of initial anamnesis collection, ad-ditional data can be received during the examination. Laboratory biomarkers, clinical predictors, understanding the mechanisms of anaphylaxis by physical triggers or their consequences, optimal options for pathogenetic therapy are still unresolved issues that require further research. The aim of this review is to provide a content analysis of current knowledge about chronic inducible urticarias in order to increase clinicians' awareness and, consequently, reduce the risk of urgent conditions associated with them.

Symptomatic dermographism (SD) is the most common form of chronic inducible urticaria, typically presenting with pruritic, linear wheals that appear within minutes after stroking the skin and resolve within 30 minutes. However, not every linear urticarial eruption following friction or scratching is true SD. We present three clinical cases initially misdiagnosed or suspected as classic SD, but which after detailed evaluation proved to be different entities. The first case was an atypical follicular subtype of SD itself, with a false-negative initial FricTest. The second case was cholinergic dermographism — a rare variant of cholinergic urticaria requiring two concurrent triggers (sweating and stroking) — in a patient with hyperhidrosis. The third case was flagellate dermatitis caused by consumption of inadequately cooked Shiitake mushrooms, with lesions persisting for days and no response to antihistamines. These cases highlight that even a characteristic linear wheal pattern is not pathognomonic for SD. A thorough history, recognition of atypical morphologies, and appropriate provocation testing (including combined triggers when needed) are essential to avoid diagnostic pitfalls and initiate effective therapy.