What causes unexplained red rashes and itching on the body?

　　In general, unexplained red bumps and itching on the body may be caused by physiological factors such as dry skin and environmental irritation, as well as pathological factors such as urticaria, eczema, and contact dermatitis. If discomfort symptoms occur, it is recommended to seek timely medical treatment at a qualified hospital. Detailed analysis is as follows:

　　1. Dry Skin

　　When the skin remains dehydrated for a prolonged period, the stratum corneum may become damaged and its barrier function weakened, making it prone to itching and red bumps. Daily routines should include reducing the frequency of bathing, avoiding excessively hot water, and applying moisturizing lotion immediately after bathing, such as Vaseline moisturizing lotion, vitamin E cream, or urea cream, to maintain skin hydration.

　　2. Environmental Irritation

　　Exposure to allergens in the environment, such as pollen, dust mites, and animal dander, or stimulation from temperature changes and excessive ultraviolet exposure, may trigger skin reactions. It is advisable to avoid known allergens as much as possible, take protective measures when outdoors, such as wearing masks and applying sunscreen, and regularly clean and dust indoor spaces.

　　3. Urticaria

　　Urticaria is characterized by dilation of small blood vessels and increased permeability in the skin and mucous membranes, leading to wheals and itching, often associated with allergies or infections. Under a doctor's guidance, antihistamine medications such as ebastine tablets, levocetirizine dihydrochloride dispersible tablets, or desloratadine granules may be used. Scratching should be avoided to prevent worsening of symptoms.

　　4. Eczema

　　Eczema is an inflammatory skin reaction caused by various internal and external factors, characterized by erythema, papules, and itching, and tends to recur frequently. As directed by a physician, calamine lotion, desonide cream, or hydrocortisone butyrate cream may be applied topically. Spicy and irritating foods should be avoided, and the skin should be kept clean and dry.

　　5. Contact Dermatitis

　　Contact dermatitis occurs when the skin reacts to certain exogenous substances, causing inflammation at the contact site, with symptoms such as erythema, papules, and itching. Contact with the allergen should be discontinued immediately, and treatment under medical guidance may include mometasone furoate cream, loratadine syrup, or fexofenadine hydrochloride tablets. Hot water washing of the affected area should be avoided.

　　In daily life, it is important to wear loose and breathable cotton clothing to avoid skin irritation from friction; maintain a regular sleep schedule to enhance immunity; follow a light diet, consume more fresh fruits and vegetables, and reduce intake of allergenic foods. If symptoms persist or worsen, seek medical attention promptly to identify the cause and receive appropriate treatment.