Sun Blister: What You Should Know

A sun blister is a fluid-filled pocket caused by a more intense sunburn; protect it, keep it clean, and seek care for severe or widespread symptoms. Blisters can appear with redness, warmth, tenderness, swelling, or later peeling. They may form hours after sun exposure and can break if rubbed by clothing or scratched.

The blister roof is a natural covering over irritated skin. Clear fluid inside is common. Do not deliberately puncture it, because opening the skin removes that protection and can allow bacteria to enter. A blister that has opened may become more painful, ooze, or develop a crust. Sunburned skin is also more vulnerable to further ultraviolet exposure, so cover the area with loose clothing and stay out of direct sun while it settles.

For more context, see [Sunburn](/conditions/sunburn/) and [Skin Blisters](/symptoms/skin-blisters/). Peeling after the inflammation improves can be part of the same healing process; avoid pulling at loose skin.

Cool the skin gently with a cool, damp cloth or a brief cool shower; avoid ice directly on the area. Pat dry, leave an intact blister alone, and wear soft, loose clothing. If it breaks, wash gently with clean water and mild cleanser, do not peel away the remaining skin, and cover it with a clean non-stick dressing. A bland moisturiser may reduce dryness once the skin is no longer hot or actively weeping; [Emollient Therapy](/treatments/medical-dermatology/emollient-therapy/) explains this approach. Drink fluids and follow the label of any pain medicine you normally can take.

Arrange prompt medical advice for extensive blistering, severe pain, marked swelling, fever, chills, vomiting, dizziness, confusion, fainting, or signs of dehydration. Seek urgent help if the skin becomes increasingly red, hot, swollen, or painful, or if pus or red streaks appear after a blister opens. Blisters involving the eyes, lips, or genitals need assessment, as do symptoms after prolonged heat exposure such as confusion or collapse. Children, older adults, and people with significant medical conditions may need earlier advice.

Do not apply steroid cream to an open blister unless a clinician has advised it. [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/) may be relevant for selected inflammatory skin problems, but treatment depends on the skin's condition and the diagnosis.

Ask whether the blister needs a dressing, which pain relief is suitable with your medicines and health conditions, and what signs of infection should prompt a review. Mention how long ago the exposure occurred, whether the blister is intact, and whether you have fever, nausea, dizziness, or eye symptoms.