Localized heat urticaria (heat contact urticaria)

Potential Therapeutic Approaches for Chronic Urticaria: Beyond H1-Antihistamines and Biologics

Chronic urticaria is a disease that can significantly impact a patient's quality of life and ability to function. There are effective treatment options, such as nonsedating antihistamines or biologics, but some patients do not respond to these therapies, or the therapies are not available or affordable to all patients. This review aims to summarize potential treatment strategies for patients (1) who do not respond to antihistamines and (2) cannot readily access or do not respond to biologics. The review emphasizes the importance of sound clinical practice, including correct diagnosis of chronic urticaria phenotypes, treatment of associated comorbidities, and consideration of add-on pharmacological and nonpharmacological approaches. Although some treatments may lack high-quality evidence, they may still be justifiable in certain cases, provided that there is shared decision-making, regular reassessment, and early recognition of adverse events.

Heat urticaria: a revision of published cases with an update on classification and management

Heat urticaria (HU) is a rare type of physical inducible urticaria, characterized by itchy erythema and well-demarcated weals appearing soon after heat exposure. Most cases occur in female patients aged 20-45 years. Both localized and generalized forms exist, depending on the limitation of the reaction to the skin area directly exposed to the physical stimulus or the involvement of distant sites, respectively. In most cases, HU is an immediate reaction, but delayed forms (mostly familial) have been described. HU is a long-lasting disease with overall duration at diagnosis of approximately 2 years. In about half of cases it is associated with systemic symptoms such as weakness, wheezing, headache, flushing, nausea, vomiting, diarrhoea, tachycardia, even dyspnoea or syncope. The main differential diagnosis includes cholinergic urticaria, exercise-induced anaphylaxis and solar urticaria. The diagnosis of HU is established by provocation testing, which is also helpful to evaluate the critical temperature threshold. The mean threshold temperature is about 44 °C. A heat desensitization programme can be an effective treatment. Nonsedating H1 antihistamines administered at licensed doses are the mainstay of symptomatic therapy in nearly 60% of patients, but full symptom relief is achieved in only a minority of them. Omalizumab has proven effective in recent case reports.

Localized heat urticaria

Localized heat urticaria is one of the rarest of the physical urticarias, characterized by well-defined urticarial lesions sharply confined to sites of heat exposure. We describe a case of localized heat urticaria in a 40-year-old woman. Because of the rarity of this disorder, much remains to be elucidated. The clinical features, pathogenesis and therapy are reviewed.