What is the first line of treatment for photodermatitis?

First-Line Treatment for Photodermatitis

Narrowband UVB (NB-UVB) phototherapy is the first-line treatment for photodermatitis, with topical corticosteroids used for symptomatic relief during acute flares. 1

Understanding Photodermatitis

Photodermatitis refers to abnormal skin reactions triggered by exposure to ultraviolet radiation. These include:

• Polymorphic light eruption (PLE)
• Chronic actinic dermatitis (CAD)
• Solar urticaria (SU)
• Actinic prurigo (AP)
• Erythropoietic protoporphyria (EPP)

Treatment Algorithm

First-line treatments:

1. Acute symptomatic relief:

   • Topical corticosteroids (medium to high potency) for 2-4 weeks
   • Hydrocortisone for mild cases, applied up to 3-4 times daily 2

2. Prevention/long-term management:

   • Narrowband UVB phototherapy (primary treatment)
   • Administered 3-5 times weekly according to minimal erythema dose (MED)
   • Initial dose: 50% of MED
   • Treatments 1-20: Increase by 10% of initial MED 1

Second-line treatment:

• PUVA (Psoralen + UVA) therapy when NB-UVB fails or triggers eruptions
• PUVA should be considered before other systemic treatments 1
• Typically administered 2-3 times weekly for 12-20 treatments

Special considerations by condition:

• Polymorphic Light Eruption (PLE):

  • NB-UVB first, PUVA if NB-UVB fails
  • Risk of provoking PLE during initial treatments (12-50% of cases)
  • Consider prophylactic potent topical steroids after each exposure 1

• Chronic Actinic Dermatitis (CAD):

  • PUVA under close supervision with topical/systemic corticosteroid cover
  • Should be performed in specialized units 1

• Solar Urticaria (SU):

  • Requires specialized phototesting to determine action spectrum
  • Treatment must be guided by patient's specific wavelength sensitivity 1

• Erythropoietic Protoporphyria (EPP):

  • NB-UVB is first choice; PUVA rarely appropriate 1

Practical Management Tips

• Timing of phototherapy: In temperate climates, administer in early spring to maximize benefit throughout summer 1

• Managing provocation episodes:

  • Apply potent topical steroids
  • Reduce dose increments
  • Omit 1-2 treatments if severe 1

• Post-treatment recommendations:

  • Continue cautious natural sunlight exposure to maintain resistance
  • Use high SPF sunscreens for extended outdoor exposure 1, 3

• Maintenance considerations:

  • Benefit typically diminishes several weeks post-phototherapy
  • Annual desensitization generally not recommended due to skin cancer risk 1

Pitfalls and Caveats

1. Risk of provocation: Initial phototherapy treatments may trigger flares, particularly with PLE

2. Long-term risks: Balance therapeutic benefit against skin carcinogenesis risk with repeated PUVA treatments

3. Specialized care needed: Conditions like CAD and SU require treatment in specialized units with expertise in phototherapy

4. Individualized dosing: Treatment must be based on minimal erythema dose (MED) and/or Fitzpatrick skin type 1

5. Maintenance challenges: The photoprotective effect may subside if administered too early in the year; if too late, patients may already have suffered eruptions 1

By following this treatment approach, most patients with photodermatitis can achieve significant improvement in symptoms and quality of life.