What causes itchy skin and red bumps?

Skin itching and red bumps may be caused by various factors, including: 1. Insect bites: After an insect bite, the skin may develop a localized inflammatory reaction or a systemic allergic reaction, manifesting as skin itching and red bumps. These often appear as isolated or scattered spindle-shaped red papules, with possible punctum or blisters on the top. 2. Eczema: Eczema is an inflammatory skin disease of unknown multifactorial origin. It presents with skin redness, swelling, itching, and possibly small bumps. Eczema can occur on multiple areas such as limbs, face, and neck. 3. Urticaria: Urticaria is associated with food, drug allergies, or infections. It presents as skin itching and red wheals of varying sizes that may spontaneously resolve within several hours but tend to recur repeatedly. 4. Contact dermatitis: When the skin comes into direct contact with allergens (such as metals, pollen, etc.), an allergic reaction may occur, presenting as redness, itching, and bumps at the contact site. 5. Solar dermatitis: Caused by ultraviolet light allergy, it commonly appears on sun-exposed areas such as the face and neck, presenting with symptoms such as small blisters and small papules, accompanied by significant itching.