Systemic photoprotection in solar urticaria with α-melanocyte-stimulating hormone analogue [Nle4-D-Phe7]-α-MSH

Br J Dermatol. 2011 Feb;164(2):407-14. doi: 10.1111/j.1365-2133.2010.10104.x.


Background: Solar urticaria is a rare photosensitivity disorder demonstrating a range of action spectra, which can inflict a very large impact on life quality despite available treatments. Melanin broadly reduces skin penetration by ultraviolet-visible wavelengths, thus increased melanization may protect in solar urticaria.

Objectives: To examine quantitatively for impact of the potent α-melanocyte stimulating hormone analogue afamelanotide ([Nle(4)-D-Phe(7)]-α-MSH, Scenesse(®); Clinuvel Pharmaceuticals Ltd, Melbourne, Vic., Australia) on the solar urticaria response and skin melanization.

Methods: Five patients with solar urticaria received a single dose of 16 mg subcutaneous afamelanotide implant in winter time. Melanin density was assessed spectrophotometrically from day 0 to day 60. Detailed monochromated light testing to geometric dose series (increment ) of wavelengths 300-600 nm was performed at 0, 30 and 60 days, with assessment of weal and flare area and minimum urticarial dose (MUD). Data were analysed by repeated-measures anova.

Results: Mean melanin density increased by day 7, peaked at day 15 and remained elevated at day 60 (P=0·03, 0·01, 0·02 vs. baseline, respectively). Baseline phototesting revealed action spectra of 320-400 (n=1), 320-500 (n=2), 300-600 (n=1) and 370-500 nm (n=1), and on afamelanotide mean rises in MUD of 1-12 and 1-3 dose increments were seen at the individual wavelengths tested, at 30 and 60 days, respectively. A significant fall in weal area occurred across responding wavelengths from 300 to 600 nm at 60 days postimplant (P=0·049 vs. baseline), accompanied by greater than twofold overall increase in MUD (P=0·058 vs. baseline).

Conclusions: Melanization following afamelanotide is accompanied by reduction in solar urticaria response across a broad spectrum of wavelengths. Further study is warranted to assess clinical benefit under ambient conditions in summer.

Publication types

  • Clinical Trial, Phase II
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Dose-Response Relationship, Drug
  • Drug Implants
  • Female
  • Hormones / administration & dosage
  • Hormones / therapeutic use*
  • Humans
  • Injections, Subcutaneous
  • Male
  • Melanins / metabolism
  • Middle Aged
  • Skin / drug effects
  • Skin / pathology
  • Skin Pigmentation / drug effects*
  • Skin Pigmentation / radiation effects
  • Sunscreening Agents / administration & dosage*
  • Ultraviolet Rays / adverse effects*
  • Urticaria / drug therapy*
  • Urticaria / metabolism
  • Young Adult
  • alpha-MSH / administration & dosage
  • alpha-MSH / analogs & derivatives*
  • alpha-MSH / therapeutic use


  • Drug Implants
  • Hormones
  • Melanins
  • Sunscreening Agents
  • alpha-MSH
  • afamelanotide