What is the first line of treatment for photo eczema (also known as photodermatitis)?

First-Line Treatment for Photodermatitis

The first-line treatment for photodermatitis (photo eczema) is avoidance of the triggering UV radiation combined with topical corticosteroids such as hydrocortisone for symptom relief.

Diagnosis and Classification

Photodermatitis (photo eczema) can be categorized into several types:

• Photo-irritant contact dermatitis (PICD)
• Photoallergic contact dermatitis (PACD)
• Photosensitive atopic dermatitis
• Other photosensitivity disorders

Treatment Algorithm

First-Line Management:

1. UV Avoidance and Protection

   • Identify and avoid triggering wavelengths of light
   • Use high SPF sunscreens
   • Wear protective clothing
   • Limit outdoor activities during peak UV hours

2. Topical Corticosteroids

   • Hydrocortisone (1%) for mild cases 1
   • Apply twice daily to affected areas
   • Indicated for temporary relief of itching, inflammation, and rashes due to eczema

3. Antihistamines

   • Sedating antihistamines are useful for severe pruritus
   • Non-sedating antihistamines have little value in photodermatitis 2
   • May require large doses in some cases

Second-Line Management (if first-line fails):

1. Phototherapy (Paradoxically)

   • Narrowband UVB (NB-UVB) is the first choice for phototherapy 2
   • Consider only after first-line treatments have failed
   • Works through "hardening" or desensitization of the skin

2. PUVA (Psoralen + UVA)

   • Should only be considered if NB-UVB has not been adequately effective 2
   • Higher risk of long-term adverse effects including premature skin aging and cutaneous malignancies

Special Considerations

For Specific Types of Photodermatitis:

• Photo-irritant reactions: Commonly caused by plants, psoralens, and medications 3

  • Focus on identification and avoidance of the irritating chemical

• Photo-allergic reactions: Often caused by sunscreens and topical NSAIDs 3

  • Requires photopatch testing for accurate diagnosis
  • Treatment centers on identification and avoidance of allergens

Common Pitfalls to Avoid:

1. Misdiagnosis: Photodermatitis can mimic other conditions like polymorphic light eruption, solar urticaria, and lupus 3

   • Consider photoprovocation testing to confirm diagnosis in unclear cases

2. Inappropriate phototherapy: Starting phototherapy without proper testing can worsen symptoms in some patients 4

   • Always determine UV sensitivity through phototesting before initiating phototherapy

3. Overlooking systemic causes: Some medications and systemic disorders can cause photosensitivity

   • Review all medications and consider systemic diseases before finalizing diagnosis

Monitoring and Follow-up

• Assess response to treatment within 2-4 weeks
• If no improvement with first-line therapy, consider referral to a dermatologist for specialized testing and treatment 2
• For recurrent or severe cases, prophylactic phototherapy during spring may be necessary 5

The management of photodermatitis requires careful identification of triggers and appropriate selection of treatments based on the specific type and severity of the condition.