Welts, medically known as urticaria or hives, are a common skin reaction characterized by raised, itchy bumps. These welts can be red or skin-colored, vary in size, and often appear suddenly on the skin. While they can occur at any time, many individuals notice these skin manifestations specifically at night.
Welts from Pests and Environment
External factors encountered at night can trigger welts. Insect bites are a common cause, especially from nocturnal biters. Bed bug bites often present as red, swollen, and itchy welts, sometimes with a dark spot at their center. These bites can appear in distinct patterns, such as lines, clusters, or zigzag formations, on exposed skin. Mosquitoes also deliver itchy, red, and swollen bites that can transform into welts.
The sleeping environment can harbor allergens that provoke skin reactions. Dust mites, microscopic organisms thriving in bedding, mattresses, and upholstered furniture, are a frequent trigger. Pet dander, tiny skin flakes, saliva, and urine proteins, can also cause hives or skin rashes upon contact. These allergens accumulate in bedrooms, increasing exposure at night. Mold spores, airborne particles released by mold, can trigger allergic responses, including itchy welts or hives.
Understanding Hives and Allergic Reactions
Beyond external irritants, the body’s internal allergic responses can manifest as welts, which are itchy, raised bumps. This reaction occurs when the immune system releases chemicals, such as histamine, causing tiny blood vessels to leak fluid into the skin.
Hives can be categorized by duration and triggers. Acute urticaria typically lasts less than six weeks and is often a reaction to specific triggers like certain foods, medications, or infections. In contrast, chronic spontaneous urticaria persists for six weeks or longer, often without an identifiable cause, and may be linked to autoimmune dysfunction. Contact dermatitis, another skin reaction, occurs when skin directly touches an irritant or allergen, such as new laundry detergents or certain fabrics, leading to an inflammatory response and welts.
Less Common Skin Reactions
Less common conditions can also cause welts that might be more apparent at night. Dermatographia, often called “skin writing,” is a condition where light scratching or pressure on the skin results in raised, inflamed lines or welts. Lying on rough bedding or rubbing against sheets can easily trigger this reaction, though the welts typically fade within 30 minutes.
Pressure urticaria involves the development of welts in areas subjected to sustained pressure. This can occur from sleeping positions or tight clothing, with welts appearing immediately or several hours later. Psychological stress can also exacerbate or trigger hives in susceptible individuals. The body’s response to stress involves the release of chemicals like histamine, which can lead to the formation of these welts.
Managing Welts and When to See a Doctor
Managing welts involves self-care and professional medical attention. For immediate relief, over-the-counter antihistamines, available as oral medications or topical creams, can help reduce itching and swelling. Applying cool compresses to affected areas can also provide soothing comfort. Avoiding scratching welts is important to prevent further irritation or infection. Identifying and removing potential triggers from the home, such as regularly washing bedding or using hypoallergenic products, can help prevent recurrence.
Seek medical advice if welts are widespread, persist for more than a few days or weeks, or recur frequently without an obvious cause. Professional evaluation is also advised if over-the-counter treatments prove ineffective, or if welts are painful, blister, or show signs of infection. Immediate emergency medical care is necessary if welts are accompanied by difficulty breathing, swelling of the face, lips, or throat, as these can be signs of a severe allergic reaction known as anaphylaxis.