👉 Erythemal is a medical term that refers to a type of skin rash or blister caused by an allergic reaction. It occurs when the immune system mistakenly attacks and inflames the skin's dermis, leading to redness, swelling, and sometimes pain. Common causes include food allergies, insect bites, pollen, and certain medications. Treatment may involve antihistamines, corticosteroids, or local application of creams with anti-inflammatory ingredients.