From the Guidelines
Papular urticaria is a common allergic skin reaction caused by insect bites, particularly from mosquitoes, fleas, bedbugs, or mites. It appears as small, itchy, red bumps or hives that can last for days to weeks, unlike typical hives which resolve within 24 hours. The condition is most common in children but can affect anyone. According to the guidelines for evaluation and management of urticaria in adults and children 1, despite thorough evaluation, many cases remain unexplained, but it may be possible to assign a specific aetiology to individual cases of urticaria. Treatment focuses on relieving symptoms with oral antihistamines like cetirizine (10mg daily for adults, adjusted for children based on weight) or diphenhydramine (25-50mg every 6 hours for adults), and topical anti-itch creams containing 1% hydrocortisone applied 2-3 times daily to affected areas. Some key points to consider in the management of papular urticaria include:
- Relieving symptoms with oral antihistamines and topical anti-itch creams
- Preventing further insect bites with repellents and protective clothing
- Avoiding scratching to prevent secondary bacterial infections
- Considering a short course of oral steroids for severe cases, as prescribed by a physician. The condition occurs because the body develops a hypersensitivity reaction to proteins in the insect saliva, causing the immune system to release histamine and other inflammatory chemicals that create the characteristic itchy bumps. Most cases resolve without complications, but scratching can lead to secondary bacterial infections requiring antibiotic treatment.
From the Research
Definition and Characteristics of Papular Urticaria
- Papular urticaria is a common and often distressing childhood disorder manifested by chronic or recurrent papules caused by a hypersensitivity reaction to the bites of mosquitoes, fleas, bedbugs, and other insects 2.
- Individual papules may surround a wheal and often have a central punctum.
- The histopathology of papular urticaria consists of mild subepidermal edema, extravasation of erythrocytes, interstitial eosinophils, and exocytosis of lymphocytes.
Diagnosis and Etiology
- The diagnosis of papular urticaria has evolved over the years and has many synonyms, with its most common present day usage relating to a cutaneous reaction presumably from an apparent exposure to insects 3.
- Insight to etiology is important and can be partially determined by clinical history and clinical pattern of symptoms.
- Increasing appreciation of the role of environmental mites and ectoparasites has allowed for more precision in diagnosis to specifically treat the cause.
Treatment and Management
- The primary challenge in therapy often relates to the achievement of the goal of symptom relief, which is often difficult because of the chronicity of the syndrome when the patient is seen by a specialist 3.
- Antihistamines, and mainly H1 antihistamines, are the mainstay of antiurticaria therapy, with second-generation antihistamines being considered first-line agents in the treatment of chronic urticaria due to their safety and efficacy profile 4, 5, 6.
- Some patients may require higher doses of H1 antihistamines alone or in combination with other classes of medications, including H2 antihistamines, leukotriene receptor antagonists, or first-generation H1 antihistamines 6.