[Solar urticaria and polymorphous light eruption]. / Lichturtikaria und polymorphe Lichtdermatose.

Solar urticaria is a rare idiopathic photodermatosis. According to the current knowledge its pathogenesis is most likely based on an allergic type I reaction to an autoantigen activated by ultraviolet (UV) radiation or visible light. As many of the patients suffer from severe forms of the disease, it may therefore severely impair the quality of life of those affected. In contrast, polymorphous light eruption is a very common disease, which, according to the current data, can be interpreted as a type IV allergic reaction to a photoallergen induced by UV radiation. As the skin lesions heal despite continued sun exposure, the patients' quality of life is generally not significantly impaired. These two clinically and pathogenetically very different light dermatoses have shared diagnostics by means of light provocation and an important therapeutic option (light hardening). Herein, we present an overview of the clinical picture, pathogenesis, diagnosis and available treatment options for the above-mentioned diseases.

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.

Chronic Urticaria in Special Populations: Pediatric, Pregnancy, and the Elderly.

Chronic urticaria is an inflammatory skin disorder defined by the presence of evanescent erythematous pruritic wheals, angioedema, or both. While treatment guidelines are continuing to become more clearly defined, there is still a gap in the medical literature surrounding chronic spontaneous urticaria (CSU) treatment in vulnerable populations such as children (aged 0-18 years), pregnant women, and the elderly (aged >65 years). The purpose of this review is to provide an update on CSU in each of these special population categories by defining prevalence, identifying diagnostic considerations, and exploring current and future management options.

Urticarial Vasculitis.

Urticarial vasculitis is a rare autoimmune disorder characterized by persistent edematous papules and plaques on the skin that last longer than 24 hours, often accompanied by systemic symptoms such as joint pain and fever. Unlike common urticaria, this condition involves inflammation of small blood vessels, leading to more severe and long-lasting skin lesions with a tendency to leave a bruiselike appearance. Diagnosis is challenging and may require a skin biopsy. Associated with underlying autoimmune diseases, treatment involves managing symptoms with medications such as antihistamines and corticosteroids, addressing the immune system's dysfunction, and treating any concurrent autoimmune conditions.

Chronic Spontaneous Urticaria: Etiology and Pathogenesis.

Urticaria, also known as hives, is a common condition thought to affect up to 20% of individuals worldwide in their lifetime. This skin condition is characterized by the appearance of pruritic, erythematous papules or plaques with superficial swelling of the dermis. The major complaint is the symptom of pruritus. Angioedema, which involves a deeper swelling of dermal or mucosal tissues, may accompany urticaria. Urticaria can be classified by both time course of symptoms and the underlying etiology.

Acetylcholinesterase is regulated by exposure of ultraviolet B in skin keratinocytes: A potential inducer of cholinergic urticaria.

Cholinergic urticaria is a dermatological disease characterized by the presence of large patches of red skin and transient hives triggered by factors, such as exercise, sweating, and psychological tension. This skin problem is hypothesized to be attributed to a reduced expression of acetylcholinesterase (AChE), an enzyme responsible for hydrolyzing acetylcholine (ACh). Consequently, ACh is thought to the leak from sympathetic nerves to skin epidermis. The redundant ACh stimulates the mast cells to release histamine, triggering immune responses in skin. Here, the exposure of ultraviolet B in skin suppressed the expression of AChE in keratinocytes, both in in vivo and in vitro models. The decrease of the enzyme was resulted from a declined transcription of ACHE gene mediated by micro-RNAs, that is, miR-132 and miR-212. The levels of miR-132 and miR-212 were markedly induced by exposure to ultraviolet B, which subsequently suppressed the transcriptional rate of ACHE. In the presence of low level of AChE, the overflow ACh caused the pro-inflammatory responses in skin epidermis, including increased secretion of cytokines and COX-2. These findings suggest that ultraviolet B exposure is one of the factors contributing to cholinergic urticaria in skin.

Update on Urticaria and Angioedema.

Urticaria and angioedema are caused by immunoglobulin E- and non-immunoglobulin E-mediated release of histamine and other inflammatory mediators from mast cells and basophils. Diagnosis is made clinically, and anaphylaxis must be ruled out if urticaria or angioedema is present. A limited nonspecific laboratory workup should be considered unless elements of the history or physical examination suggest specific underlying conditions. The mainstay of treatment is avoidance of triggers when and if triggers are identified. The first-line pharmacotherapy is second-generation H1 antihistamines, which can be titrated to greater than standard doses.

Overexposure to ultraviolet radiation in solar urticaria.

A man in his 50s was diagnosed with solar urticaria following monochromated light testing that demonstrated exquisite photosensivity to ultraviolet (UV) A, UV B (UVB) and visible light.Treatment options for this photodermatosis are limited; UVB phototherapy is one modality that can be appropriate in some patients. This is administered at very low doses in a controlled environment to induce skin hardening.1 To self-treat his condition, the patient used a commercial sunbed on two occasions several days apart. He noted an immediate flare of solar urticaria after first use with associated dizziness. Following the second use, he felt generally unwell and was witnessed to lose consciousness and displayed jerky movements of his limbs while a passenger in a car. Investigations including a head MRI and an EEG were normal; an anoxic seizure caused by a flare of solar urticaria was later confirmed.Solar urticaria is a rare photodermatosis that is poorly understood and difficult to treat. The condition has a significant impact on the quality of life of patients. Severe cases can be associated with systemic symptoms that could be life-threatening.

The role of the environment in allergic skin disease.

PURPOSE OF REVIEW: This paper explores how environmental factors influence allergic skin diseases, including atopic dermatitis (AD), contact dermatitis (CD), urticaria, angioedema, and reactions to drugs and insect bites. RECENT FINDINGS: Research indicates a significant impact of environmental elements on allergic skin diseases. High air pollution levels exacerbate symptoms, while climate change contributes to increased skin barrier dysfunction, particularly affecting AD. Allergen prevalence is influenced by climate and pollution. Irritants, like those in detergents and cosmetics, play a major role in CD. Plants also contribute, causing various skin reactions. Understanding the interplay between environmental factors and allergic skin diseases is crucial for effective management. Physicians must address these factors to support patient well-being and promote skin health amidst environmental changes.

Overview of Dermatological Manifestations Associated with the COVID-19 Infection.

COVID-19 is an infectious disease caused by SARS-CoV-2 that is characterized by respiratory symptoms, fever, and chills.[1] While these systemic symptoms are widely known and well understood, there have also been reports of dermatological manifestations in patients with COVID-19. These manifestations include chilblain-like lesions, maculopapular lesions, urticarial lesions, necrosis, and other varicella-like exanthems.[2] The pathogenesis of these lesions are not well understood, but the procoagulant and pro-inflammatory state induced by COVID-19 infections may be contributing to varied cutaneous manifestations.[3] Drug interactions and concurrent hypersensitivity reactions have also been postulated.[4] This review aims to compile and analyze various retrospective studies and case reports to summarize the clinical presentation of dermatological lesions associated with COVID-19 infections and suggest further areas of research.

Cold-induced anaphylaxis triggered by drinking cold water.

Cold urticaria is an inducible urticaria in which hives and angioedema appear after exposure to cold. The symptoms of cold urticaria often are limited to hives/angioedema. However, in up to 20% of cases, cold exposure may trigger anaphylaxis. We report the case of an 11-year-old boy previously diagnosed with chronic spontaneous urticaria who developed facial swelling, itchy hives, difficulty in breathing, vomiting and abdominal pain within 5 minutes of drinking cold water. He received a standard dose of non-sedating second-generation antihistamines at home. He was observed in the emergency room for 2 hours and discharged with an epinephrin autoinjector. During the subsequent outpatient clinic visit, an ice cube test was performed which confirmed the new diagnosis of comorbid cold-induced chronic urticaria. On further questioning, the parents reported occurrence of hives following swimming in the swimming pool. Cold-induced urticaria should be suspected in cases of anaphylaxis associated with cold exposure. Patients with chronic forms of urticaria who present with new anaphylaxis should be assessed for a potential concomitant cold-induced form.

Clinical Features and Outcomes of Acute versus Chronic Urticaria Triggered by COVID-19 Infection.

OBJECTIVE: Although acute urticaria (AU) and urticaria-like rash are commonly reported with COVID-19 infection, chronic spontaneous urticaria (CSU) triggered by COVID-19 is rare. The authors compared the features of COVID-19 infection-induced chronic CSU and AU to determine which patients' COVID-19 infection leads to CSU and possible indicators of chronicity. METHODS: The authors retrieved the charts of patients diagnosed with AU or CSU following COVID-19 at the Urticaria Centers of Reference and Excellence and compared patients in terms of demographic characteristics, length of time between infection and onset of urticaria, duration of urticaria, COVID-19 disease severity, laboratory test results, vaccination, and treatment status. RESULTS: A total of 92 patients were included in the study: 7 with CSU following COVID-19 and 85 with AU after COVID-19. The mean duration of urticaria for CSU and AU following COVID-19 was 13.0 ± 6.0 months and 7.1 ± 3.4 days, respectively. The average time between COVID-19 and the start of urticaria was longer in the CSU group (20.7 ± 3.9 days vs 4.5 ± 2.8 days, respectively; P = .000). No between-group differences were found for any other parameters. CONCLUSIONS: The onset of urticaria more than 2 weeks after COVID-19 infection may serve as an indicator for urticaria chronicity beyond 6 weeks and may help physicians predict the possible course of urticaria associated with COVID-19 infection. The relevance of basopenia and eosinopenia needs to be determined.