Cetirizine for solar urticaria in the visible spectrum

Les anti-H1 en pratique dermatologique

INTRODUCTION

Histamine is an inflammation mediator that is fundamental for the development of some allergic reactions and is also implied in several common dermatological affections. Anti-H1s are molecules capable of couteracting the effect of histamine on its specific receptors. There are two types: first generation anti-H1 and second generation anti-H1.

OBJECTIVE

To assess the efficacy of anti-H1 in the treatment of skin diseases.

PATIENTS AND METHODS

A reference search was made using the Pubmed data bank. Critical analysis was made of the articles selected based on their evidence.

RESULTS AND CONCLUSION

Demonstration of the efficacy of anti-H1 was only confirmed in a few dermatitis. Urticaria is the indication of choice. The symptomatic use of anti-H1 may be justified within the context of other dermatitis. The second rather than the first generation molecules should be preferred because of the lesser side effects and improved pharmacokinetic profile.

Urticaria solar. Estudio de 20 casos

INTRODUCTION

Solar urticaria is an infrequent disorder, but is probably underdiagnosed. It is characterized by the sudden appearance of weals in areas that are not usually photoexposed after exposure to the sun or to artificial sources of visible or ultraviolet light. Few cases have been published in literature, so the information available about this disorder and its natural evolution is limited.

MATERIAL AND METHODS

We have compiled data from 20 patients diagnosed with solar urticaria in our department in the last 12 years (1990-2002) in order to try to obtain information about the characteristics of this condition.

RESULTS

As the most relevant characteristics of our series, we can mention the fact that 60 % of the patients were women, and the average duration of the condition before consulting a dermatologist was 3 years. In 55 % of the patients, areas that are usually photoexposed, such as the face and hands, were less severely affected (due to acclimatization or hardening). The spectra responsible for the SU were visible light, UVA and UVB, in that order. With regard to treatment, we obtained a partial response with antihistamines and photoprotectors, and good results using progressive desensitization with UVA/sunlight.

CONCLUSION

Solar urticaria is probably an underdiagnosed condition in our milieu. There are few series in literature that provide any information about the most significant characteristics of this disorder. We have compiled the most relevant data from our patients and we have compared it with the other published series in an attempt to learn more about this photodermatosis.

Second-Generation Antihistamines

Antihistamines are useful medications for the treatment of a variety of allergic disorders. Second-generation antihistamines avidly and selectively bind to peripheral histamine H1 receptors and, consequently, provide gratifying relief of histamine-mediated symptoms in a majority of atopic patients. This tight receptor specificity additionally leads to few effects on other neuronal or hormonal systems, with the result that adverse effects associated with these medications, with the exception of noticeable sedation in about 10% of cetirizine-treated patients, resemble those of placebo overall. Similarly, serious adverse drug reactions and interactions are uncommon with these medicines. Therapeutic interchange to one of the available second-generation antihistamines is a reasonable approach to limiting an institutional formulary, and adoption of such a policy has proven capable of creating substantial cost savings. Differences in overall efficacy and safety between available second-generation antihistamines, when administered in equivalent dosages, are not large. However, among the antihistamines presently available, fexofenadine may offer the best overall balance of effectiveness and safety, and this agent is an appropriate selection for initial or switch therapy for most patients with mild or moderate allergic symptoms. Cetirizine is the most potent antihistamine available and has been subjected to more clinical study than any other. This agent is appropriate for patients proven unresponsive to other antihistamines and for those with the most severe symptoms who might benefit from antihistamine treatment of the highest potency that can be dose-titrated up to maximal intensity.

Solar urticaria in Singapore: an uncommon photodermatosis seen in a tertiary dermatology center over a 10-year period

BACKGROUND

Solar urticaria is an uncommon photodermatosis, characterized by the appearance of pruritic wheals after sun exposure. In this study, we examine the photobiological characteristics of solar urticaria in the heterogeneous group of Singaporean patients.

METHODS

The photobiological features of all patients treated for solar urticaria at a tertiary dermatology center in Singapore over a 10-year period were retrospectively examined.

RESULTS

A total of 19 patients were diagnosed to have solar urticaria from 1993 to 2002. The mean age at diagnosis was 26 years, with a racial distribution of 17 (90%) Chinese, one (5%) Malay, and one (5%) Indian. Fifteen (79%) patients were males and four (21%) were females. The face/neck (47%) and arms/forearms (58%) were most often affected. Six (32%) patients had a history of atopy and two (11%) had dermographism. Fifteen (79%) patients had Fitzpatrick's skin type IV, three (16%) had skin type III and one (5%) patient had skin type V. The mean exposure time to wheal formation was 23 min. The action spectra of solar urticaria were visible light for 12 (63%) patients, ultraviolet (UV) A for one (5%), visible light and UVA for five (27%), and natural sunlight for one (5%) patient. All patients reported partial improvement with a combination of antihistamines and sunscreens as the main modality of treatment.

CONCLUSIONS

Our data suggest that solar urticaria is an uncommon photodermatosis and a rare form of urticaria. Wheals were mostly elicited by visible light and/or UVA. A combination of antihistamines and sunscreens provided a useful form of therapy for patients with solar urticaria.

Diagnosis and treatment of solar urticaria

Solar urticaria is one of the most annoying of the photodermatoses. It can be difficult to diagnosis because of phototesting problems, and it is not easy to treat. The different treatment modalities available all have their practical problems, so it is difficult to provide the patient with adequate protection. In many patients, however, treatment can reduce the symptoms and allow regular exposure of the skin to natural sunlight as the skin becomes more tolerant to the provoking wavelengths, the result being more complete protection.

Topical steroids under wet-wrap dressings in atopic dermatitis--a vehicle-controlled trial

BACKGROUND

The wet-wrap dressing technique has proved to be beneficial in cases of exacerbated atopic dermatitis (AD) skin lesions.

OBJECTIVE

The effect of wet-wrap dressings was investigated in a controlled trial comparing a steroid (mometasone furoate 0.1%)-containing and a steroid-free (vehicle) preparation in an in-patient comparison study.

METHODS

20 children aged 2-17 years with exacerbated AD were treated twice daily with wet-wrap dressings over a 5-day period.

RESULTS

AD in treated areas significantly improved in both study arms; however, the effect was significantly better in the mometasone-treated group (p < 0.01). Transepidermal water loss improved in both arms without any significant differences. Staphylococcus aureus colonization decreased during the first 3 days of active treatment independently of the therapeutic modalities chosen. At day 5, colony counts further dropped on the steroid-treated lesions.

CONCLUSION

Application of the wet-wrap dressing technique for exacerbated AD lesions is effective, combination with a topical steroid being superior to a steroid-free application without bearing the risk of a bacterial superinfection.

Treatment of urticaria. An evidence-based evaluation of antihistamines

Urticaria is a cutaneous syndrome characterized by dermal edema (wheal) and erythema (flare) that blanches with pressure. The lesions typically last less than 24 hours and are usually pruritic. In 1983, Christensen and Maibach summarized the theory behind the use of histamine H1 receptor antagonists (antihistamines) in clinical dermatology. These agents remain the mainstay of treatment for urticaria. This article reviews the medical literature on the effectiveness of antihistamines in urticarial syndromes, including acute, chronic idiopathic and the physical urticarias. Older antihistamines, such as chlorpheniramine and hydroxyzine, are effective in the treatment of urticarias, but they also have marked sedative and anticholinergic effects. Newer nonsedating antihistamines (second-generation antihistamines) have been developed that have reduced adverse effects because they do not cross the blood-brain barrier; these agents (acrivastine, cetirizine, loratadine, mizolastine, fexofenadine, ebastine, azelastine and epinastine) cause significantly less sedation and psychomotor impairment than their older counterparts. A review of the literature reveals that there are few studies which document the efficacy of second-generation antihistamines in the treatment of acute urticaria, a biologic entity that usually resolves within 3 weeks. We did not identify controlled studies that suggested superiority of any antihistamine in the treatment of acute urticaria. Loratadine or cetirizine, and possibly mizolastine, appear to be treatments of choice for chronic idiopathic urticaria. For symptomatic dermatographism, the combination of an antihistamine and an H2 antagonist, e.g. chlorpheniramine and cimetidine, appears to be effective. Very few studies have been conducted on the use of antihistamines in the treatment of cold, cholinergic, and pressure urticaria. Antihistamines are the mainstay of urticarial therapy. This evidence-based review suggests that there are efficacy differences between newer, nonsedating antihistamines and older agents in some forms of the disorder. Clearly, further well-controlled clinical trials in larger numbers of patients are needed to clarify the role of these agents in the treatment of urticaria.