Clinuvel Pharmaceuticals (ASX: CUV) has received ethical approval to begin Phase II testing of its solar urticaria (SU) treatment.

SU is a severe but rare disease that effects less than one per cent of the population. An SU sufferer's skin becomes badly sunburned after limited contact with the sun.

More prolonged exposure can cause red welts to appear on the skin, and can cause fainting, nausea and headaches. Symptoms last up to 24 hours.

Clinuvel hopes its new photo-receptive drug, CUV1647, can prove an effective preventative treatment for SU sufferers.

CUV1647 is expected to have a number of applications in the treatment of human diseases caused by abnormal quantities of melanin in the skin.

The trial will be conducted at Hope Hospital in Manchester in the UK.