About Sun Rashes
There are a number of conditions which leave skin red and itchy. Sun rash and sun allergy are often used to describe the condition, especially when it occurs after being in the sun. The most common form of sun rash is called polymorphic light eruption (PMLE). Another type of reaction, solar urticaria, is more closely aligned with allergy.
PMLE may be genetic
Reactions to the sun could be genetic, often times found in people with Native American heritage. PMLE is also experienced by people who are not acclimated to intense sun exposure. People who live in northern climates taking a vacation in the Caribbean would be an example. Symptoms of this severe skin rash appear several hours after sun exposure and may include small bumps over the sun-exposed areas of skin, dense clumps of small bumps, and hives on the extremities.
The hereditary type of PMLE presents differently. Redness, burning and itching can last a few days or weeks. Symptoms can also include fatigue, chills, headache and nausea. It may be experienced periodically throughout the summer months.
Solar urticaria presents more like an allergy
Symptoms of solar urticaria include itchiness, redness, blisters, wheezing, dizziness and even loss of consciousness in severe episodes. Antihistamines can be used for quick relief, but a doctor's advice may be necessary for long term care.
Treatment for a sun rash
Mild cases don't need treatment. More severe cases can benefit from steroid cream or pills. If you have severe reactions to the sun, preventive measures are strongly advised. First, limit your exposure to the sun, especially when it is most intense between 10am and 4pm. Also, use sunscreen all the time. A high SPF sunscreen that specifically blocks ultraviolet A and ultraviolet B rays is most important to incorporate into a daily routine. Reapply often. Finally, cover up your skin. A broad-brimmed hat, long sleeves, scarves, long pants or long socks should all be used to protect your skin. The more tightly woven the fabric is the better.
Source: Mayo Clinic, WebMD