Although the UK summer weather can be unpredictable at times, most people who have psoriasis find that the sun helps to improve their skin’s appearance. For some, the change is dramatic, with red scaly patches almost disappearing altogether during summer months in a warm climate.
As with any source of UV, sunlight comes with some dangers. UVA wavelengths penetrate the deeper layers of the skin and are largely responsible for the tanning effect of the sun. However, UVA can eventually cause damage to the skin, resulting in the typical signs of photoaging: wrinkles, broken veins, sagging skin, and age spots. Meanwhile, UVB is largely responsible for sunburn. It is thought that episodes of severe sunburn, especially in young people, increase the risk of melanoma skin cancer in the future. Also, a bad sunburn can cause psoriasis to start where the skin is burned, this is called the Koebner phenomenon.
Sun sensitivity
It is a good idea to understand the risks and in particular your sun sensitivity. The Fitzpatrick photo typing scale, which describes how the skin reacts to sun exposure, was developed in 1975 by Thomas B. Fitzpatrick, the American dermatologist, as a way to classify the typical response of different types of skin to sunlight. The Fitzpatrick scale remains a recognised tool for dermatological research into human skin pigmentation.
So what type are you?
Type 1: Pale white; blond or red hair; blue eyes; freckles — Always burns, never tans
Type 2: White; fair; blond or red hair; blue, green, or hazel eyes — Usually burns, tans minimally
Type 3: Cream white; fair with any hair or eye colour; quite common — Sometimes mild burn, tans uniformly
Type 4: Moderate brown; typical Mediterranean skin tone — Rarely burns, always tans well
Type 5: Dark brown; Middle Eastern skin types — Very rarely burns, tans very easily
Type 6: Deeply pigmented dark brown to black — Never burns, tans very easily.
So, it is wise to gradually expose your skin to the sun to avoid sunburn. Excessive lifetime exposure to all wavelengths of sunlight can increase the risks of skin cancers, and this has been illustrated in the great increase in the number of skin cancers seen in recent decades since overseas holidays have been affordable and widely available. You are at the highest risk if you are fair and your skin does not tan easily.
Remember, appropriate clothing becomes your first line of defence against the burning and blistering which could lead to the Koebner phenomenon. Sunscreens with a sun protection factor (SPF) for your skin type, clothing, a hat, and UV-protective sunglasses should become your friends.