Sunburn Effects: How UV Radiation Damages Your Body

Sunburn (solar erythema) is an acute inflammatory response to UV radiation (UVB 290–320 nm, UVA 320–400 nm) causing direct DNA damage and oxidative stress.

1. Acute Inflammation

• Erythema peaks 12–24 hrs; pain, edema, warmth
• Mediators: prostaglandins, cytokines (IL-1, TNF-α), ROS
• Vasodilation, neutrophil infiltration

2. DNA Damage and Mutagenesis

• Direct (UVB): Cyclobutane pyrimidine dimers (CPDs), 6-4 photoproducts
• Indirect (UVA): ROS → 8-oxoguanine, strand breaks
• p53 mutations → clonal expansion → squamous cell carcinoma (SCC), basal cell carcinoma (BCC)
• Melanoma: Intermittent intense exposure (sunburns) → BRAF/NRAS mutations

3. Photoaging (Chronic)

• Collagen/elastin degradation (MMP upregulation)
• Wrinkles, laxity, leathery texture, telangiectasias
• Solar lentigines ("age spots"), actinic keratoses (premalignant)

4. Severe Sunburn (Sun Poisoning)

• Blistering (2nd degree), fever, chills, nausea, headache
• Fluid/electrolyte imbalance → dehydration, hypotension
• May require IV fluids, hospitalization

5. Immune Suppression

• UV → local and systemic immunosuppression
• Impaired antigen presentation, Treg activation, ↓ Langerhans cells
• Increased susceptibility to infections, reduced vaccine efficacy
• Lasts days to weeks

6. Ocular Damage

• Photokeratitis (corneal "sunburn")
• Cataracts (cortical, posterior subcapsular)
• Macular degeneration (UVA/blue light)
• Pterygium, pinguecula

7. Long-Term Carcinogenesis

• Cumulative UV dose → SCC, BCC
• Intermittent high-dose (sunburns) → melanoma
• Childhood burns especially potent for melanoma risk

Prevention: The Only Cure

• Broad-spectrum SPF 30+ (UVA+UVB)
• Reapply q2h, after swim/sweat
• Seek shade 10 AM–4 PM
• UPF 50+ clothing, wide-brim hat, UV-blocking sunglasses
• Avoid tanning beds (Group 1 carcinogen)

Every sunburn adds to your lifetime skin cancer ledger. The skin remembers.