Contact Urticaria and Related Conditions. Clinical Review

Contact urticaria (CoU) is an immediate contact reaction occurring within minutes to an hour after exposure to specific pro-teins or chemicals. CoU is categorised into non-immunologic (NI- CoU) and immunologic (I- CoU) types, with I- CoU potentiallyleading to anaphylaxis. Both forms of CoU can be associated with protein contact dermatitis and the CoU syndrome. Patientswith I- CoU may also have other type I (immediate) allergic diseases, such as allergic conjunctivitis, rhinitis, asthma or foodallergy. This review provides a detailed overview of CoU and related conditions, focusing on triggers, diagnostic methods andmanagement strategies. NI- CoU is typically triggered by low molecular weight chemicals, while I- CoU involves IgE-mediatedhypersensitivity to both high molecular weight proteins and low molecular weight chemicals. Early diagnosis is crucial, thoughCoU is often underrecognized. The diagnostic approach includes a thorough medical history, physical examination, evaluationof photographs, (non)invasive skin tests and in vitro assessments. Management strategies prioritise trigger avoidance and phar-macological treatments when avoidance is not fully possible. For I- CoU, second-generation H 1-antihistamines are the first-linetreatment. Severe cases of I- CoU may benefit from anti-IgE therapy (omalizumab). Patients at risk of anaphylaxis should carryan adrenaline auto-injector and wear a medical alert bracelet.