Symptoms of Sunburn
Sunburn presents with erythema (redness), pain, and edema (swelling) that typically peaks within 12-24 hours after UV exposure, followed by hyperpigmentation and skin peeling. 1
Primary Clinical Manifestations
The acute sunburn reaction develops through a predictable timeline:
Immediate to Early Phase (0-24 hours)
- Erythema (skin redness) - the hallmark sign that develops dose-dependently based on UV exposure intensity 2
- Skin warmth and tenderness
- Edema (swelling) of affected areas
- Pain - can range from mild discomfort to severe burning sensation 3
Peak Phase (12-36 hours)
Research demonstrates two distinct peaks of inflammation: the first at approximately 12 hours and a second, often more pronounced peak at 36 hours post-exposure 3. During this phase:
- Maximal erythema - skin appears bright red to deep crimson
- Severe pain and burning - patients describe sensations ranging from stinging to intense burning 4
- Blistering - in severe cases, fluid-filled blisters form, indicating second-degree burns 2, 5
- Increased skin blood flow - measurable with laser Doppler, persisting beyond 96 hours 3
Hyperalgesia (Heightened Pain Sensitivity)
A critical but often overlooked feature is the development of both:
- Heat hyperalgesia - pain threshold can drop by up to 7.7°C from baseline 3
- Pressure hyperalgesia - mechanical pain threshold decreases significantly 3
- This maximal hyperalgesia coincides with the second blood flow peak between 30-60 hours post-exposure 3
Severe Variant: "Hell's Itch"
A rare but debilitating complication called "Hell's Itch" can emerge 24-72 hours after UV exposure, characterized by:
- Intense, burning pruritus (itching) described as "fire ants" or "thumbtacks" on the skin 4
- Severity rating of 8-10/10 on pain scales
- Resistance to standard treatments - antihistamines, topical lidocaine, NSAIDs, and aloe vera are typically ineffective 4
- No associated rash or fever 4
Late Phase (Days to Weeks)
- Hyperpigmentation - darkening of affected skin 1
- Desquamation (peeling) - shedding of damaged epidermis 1
- Gradual resolution of erythema and pain
Systemic Symptoms
In extensive sunburns (>10% body surface area in adults, >5% in children):
Warning Signs Requiring Emergency Evaluation
Immediate EMS activation is warranted for 5:
- Facial burns with signs of inhalation injury
- Difficulty breathing
- Singed nasal hairs or soot around nose/mouth (indicating potential airway compromise)
- Burns involving face, hands, feet, or genitals (require specialized burn center care) 5
- Large surface area involvement (>10% adults, >5% children) 5
Important Clinical Pearls
The severity of sunburn correlates directly with future skin cancer risk. Severe, blistering sunburns are specifically associated with increased risk for both melanoma and basal cell carcinoma 2. This is particularly concerning when occurring during childhood or adolescence, as these early exposures play a disproportionate role in future melanoma development 2.
The visible inflammatory response (erythema and edema) represents only the surface manifestation of deeper DNA damage to epidermal cells - damage that persists regardless of symptomatic treatment 6. This underscores why prevention through UV avoidance remains far superior to any post-exposure treatment 1.