Solar Urticaria

Symptoms

Solar urticaria are hives (large, itchy red bumps) that develop after only a few minutes of exposure to sunlight. The hives appear within 10 minutes of sun exposure and go away within an hour or two after leaving the sunlight. The rapid onset and disappearance of the reaction is a trademark of solar urticaria.  People with large affected areas often have headaches and feel weak and nauseated. [Merck Manual Home Edition] Skin cells containing potent chemicals (histamine) release these after sunlight exposure and cause blood vessels to dilate. The patient feels itchy and notices red patches which may become swollen. It may look like nettlerash or wheals. The reaction subsides within an hour of sunlight avoidance. A flare does not cause any residual damage to the skin. [Dundee] Solar urticaria is a rare photodermatosis characterized by pruritus (itching), stinging, erythema (redness), and wheal formation after a brief period of exposure to either natural sunlight or an artificial light source emitting the appropriate wavelength. The reaction is localized to exposed areas of the skin, but can occur through thin clothing. Solar urticaria disappears rapidly within several minutes to a few hours without pigmentary change, if further sun exposure is avoided. The reaction leaves no residual skin changes. This disorder can be quite disabling and difficult to manage.

Patients may complain of pruritus (itching), erythema (redness), and wheal formation of varying degrees after a short period. Like most other photodermatoses, skin lesions in solar urticaria may occur on any exposed area, even if skin was covered with thin clothing. Face and dorsal aspect of the hands, which chronically are exposed to the sun, are affected less severely than other parts of the body, perhaps due to acclimatization and "hardening".  Mucosal involvement (eg, tongue, lip swelling) has been reported. Other symptoms, such as headache, nausea, vomiting, bronchospasm, and syncope, have been reported, but are considered rare. Upon cessation of sun exposure, the rash begins to disappear within several minutes to a few hours and rarely lasts beyond 24 hours. Rapid disappearance of the rash when avoiding further sun exposure is essential to the diagnosis of solar urticaria. [Emedicine]

If a large enough area of the body is affected, the loss of fluid into the skin may result in light-headedness, pallor and nausea. It's important if you have this complaint to avoid developing a state of shock by limiting the affected areas. It is potentially serious if large areas of the body are exposed (ie sunbathing). You will feel light headed, nauseated and go pale. One or two cases of swimmers collapsing has been described.[Dundee]

Statistics:

• Solar urticaria comprises only 4% of US patients with photosensitive disorders.
• Internationally, solar urticaria comprises 5.3% of the cases of photosensitive dermatoses worldwide. [Emedicine]
• About 40% of people with solar urticaria are sensitive to UVB and UVA light. [Entrez PubMed]
• About 60% of them are sensitive to UVB, UVA and visible light.[Entrez PubMed]
• Solar urticaria is less than 1% of people with urticaria.
• Solar urticaria occurs in all races with a slight preference for females.[Emedicine]
• Solar urticaria has a wide range of onset (10-70 y) with a mean age of 35 years. It has been reported to occur in infancy. [Emedicine]
• The disease typically persists for years and but may resolve spontaneously. In about one fourth of cases solar urticaria is associated urticaria or a history of atopic dermatitis.[photodermatology]
• Is it hereditary? No! [Dundee]
• See the Scotland study of 87 solar urticaria patients.

Causes of solar urticaria

THIS SECTION NEEDS MORE WORK

It seems that sunlight generates a "photoallergen" in your skin and the immune system reacts against this, resulting in histamine release. Nobody knows what triggers it initially. Some people develop it after taking Chlorpromazine (Largactil) a major sedative. Some patients with erythropoietic protoporphyria (a rare condition) also have solar urticaria. Tar and pitch have provoked solar urticaria in some patients.[Dundee]

Is it hereditary? No! [Dundee]

Chronic medical conditions or an illnesses or allergens can cause chronic hives, and some folks are "cured" by solving things that are wrong with their body. (For example, I had a remission from solar urticaria after being treated for bronchitus.) See Causes of Urticaria to see if any of the conditions might apply to you.

Sunscreens and  avoidance:

Avoiding the sun or even indoor lights is the best protective measure with the smallest side effects. Wear protective clothing, sunscreens, and conside using using UV protective shields over glass windows. Try altering lifestyle to minimize the time spent outside during the day (ie, changing job hours or shifting to indoor recreational activities). Some patients with UV-A or visible induced solar urticaria may also find the use of self-tanning lotions containing dihydroxyacetone helpful. [Emedicine]

Most patients with solar urticaria have provocative wavelengths in the UV-A and visible ranges, especially green or blue. Most sunscreens protect against UV-B light. About 40% of people with solar urticaria are sensitive to UVB and UVA light, and about 60% of them are sensitive to UVB, UVA and visible light.

• UVB sunscreen rating - measured with spf rating which measures sunburn protection. Most commercial sunscreens protect against.
• UVA sunscreen rating - measured with ppd rating which measures tanning or persistent pigment darkening.
• Visible or blue light rating - there is no rating and sunscreens for visible light are very rare. See the  Visible light sunscreens web page.

See the sunscreen web pages (left menu) for more information about suitable sunscreens. The most highly recommended and tested sunscreen is Anthelios XL, SPF 60, PPD 28 which protects against both UVA and UVB light. You want a high SPF or high PPD in a sunscreen. For those of us sensitive to visible light, there are no commercial sunscreens that protect against visible light. See the  Visible light sunscreens web page.

Solar Urticaria links:

Emedicine solar urticaria article is written for doctors, and it includes recommended treatment options including antihistamines. This would be good to print out and take with to your doctor.
http://www.Emedicine.Com/derm/topic448.Htm

Here is a 33 page document on urticaria and angioedema if you want to do some reading. Http://www.Harcourt-international.Com/e-books/pdf/740.Pdf

Histamine Avoidance Diet

Have you noticed your allergic symptoms worsen after eating eggs, shellfish, fish, strawberries, pineapple, tomatoes, chocolate or drinking  alcohol, especially wine and beer? For those of us with allergies, our bodies responding to allergies produce  too much histamine, and that is why we take "anti"-histamines. Some foods that contain large amounts of histamine or release histamine can cause bad allergic symptoms. In particular, alcohol such as red wine can be a major trigger. (I have found the histamine avoidance diet to be very helpful in reducing my allergic symptoms.)

Drug Treatments

Do consult with your doctor regarding any treatments or medical advice suggested by this website.

Antihistamines: The allergic reaction causes histamine to be released. "Anti" histamines block histamine receptors and help stop the runaway allergic reaction. So it is good to take antihistamines before you except a reaction to take place. (I take antihistamines on a daily basis, and I have found them to be very helpful in reducing my symptoms.) Prescription strength Cetirizine (Zyrtec) and Fexofenadine (Allegra) seem to the preferred antihistamines, but over the counter antihistamines like Claritin (24 hour non-sedating) or Benadryl (sedating) can also be helpful. Note that Benadryl is good to take after an allergic episode and better for swelling like angioedema. In addition to H1 type antihistamines, you might try adding an H2 antihistamine such as Ranitidine (Zantac) which helps with stomach symptoms. For more drug treatment information see  [Emedicine].

Because solar urticaria involves IgE-mediated mast cell degranulation with consequent histamine release, the first line of treatment consists of long-acting, nonsedating antihistamine H1 blockers. Often such agents will achieve a protective factor of 10 or more. The extent to which this will be useful depends on severity of disease itself. For example, someone who gets hives after just a few seconds of sun exposure is unlikely to benefit from antihistamine monotherapy. A patient requiring 10 min or more of exposure would show more benefit. Antihistamines seem to be able to block wheal response and minimize pruritus (itching), but do not eliminate erythema reaction entirely. This tendency should be explained to the patient. [Emedicine]

Antimalarials such as hydroxychloroquine (Plaquenil)  are used to treat certain photosensitive eruptions including solar urticaria. Their efficacy, however, is unpredictable.  [Emedicine]

Other Treatments

In antihistamine resistant cases of solar urticaria, photochemotherapy with increasing exposures to oral PUVA has shown to be effective. In cases of particularly sensitive patients UVA, broadband UV-B or narrowband UV-B initially may be required as a PUVA pre-desensitation.  Desensitisation phototherapy or photochemotherapy. Patients are treated three times weekly for five weeks in an irradiation cubicle. This causes skin thickening and pigmentation which protect the patient, and allows exposure thereafter to direct sunlight to keep the effect topped up.[Dundee]

Phototherapy:
Phototherapy with UV-A, broadband UV-B, or narrowband UV-B, as well as photochemotherapy with oral 8-MOP plus UV-A successfully are used in solar urticaria. Desensitization treatments usually are performed in the spring. Unfortunately, the tolerance induced by these modalities is often short lived and maintenance therapy is needed. [Emedicine]

UVA rush hardening:
Recently UVA rush hardening for the treatment of solar urticaria has been reported. Patients with solar urticaria were exposed to multiple UVA irradiations at 1-hour intervals per day. With this rush hardening regimen, protection was achieved within 3 days. The induction of tolerance by subsequent irradiation might be a very effective therapy, however it is very time-consuming.[photodermatology]

PUVA therapy:
PUVA can achieve disease improvement or remission lasting several months. Based on the available evidence, it is probably the treatment of choice for patients not sufficiently helped by antihistamines.[Emedicine] Click for more information on PUVA therapy.  Extracorporeal Photochemotherapy (Photopheresis) might be of some benefit in serum-factor negative patients with recalcitrant cases of solar urticaria (publication in press). [photodermatology]

Plasma exchange therapy:
Plasmapheresis - a technique in which some of the patient's blood plasma is removed by machine and the red blood cells are then returned to the patient's circulation. This removes a circulating factor from the blood that may be involved in causing the urticaria, and is demonstrably present in a small proportion of patients. The technique is still being evaluated and is not always effective. Plasma exchange therapy has been reported effective in a few cases, especially in those patients with a circulating factor in their serum demonstrated by a positive intradermal test. On the contrary, therapy has been reported ineffective in some centers. Until more definitive studies are conducted to evaluate the efficacy of this therapy, it should be reserved as a last resort.[Emedicine] In patients with a detectable serum factor the removal of this by plasmapheresis has been used successfully and resulted in clinical remissions persisting for several month. It should be used when when other treatments have failed.[photodermatology]

Oral Cyclosporin A has be reported to be effective in severe cases of solar urticaria where other treatments have failed.[photodermatology]

Recently a case has been reported about the successful treatment of a severe solar urticaria by intravenous immunoglobulin, but further investigations are required. [photodermatology]

In recalcitrant cases antimalarials, doxepin, indomethacin and beta-carotene were used to treat solar urticaria. The efficacy is unpredictable. [photodermatology]

Search PUBMED for Solar Urticaria:

Click Search and enter "solar urticaria" or any other search term that you may want to find. The pubmed search should give research results on the topic you are interested in.