People suffering from pollen allergies, atopic dermatitis or allergic asthma are often advised spend a holiday at the seaside or in the mountains. Pollen levels decline significantly at altitudes over 2,000 metres, and mites cannot survive above 1,600 metres. The dry mountain air also makes life difficult for mould spores.
The sea has similar positive effects on health. The damp sea air contains few pollutants. The high level of salt and the minerals in the water alleviate the symptoms of skin diseases such as atopic dermatitis. Nearly all atopic dermatitis patients experience an improvement in skin condition, reports Angela Schuh of the Ludwig Maximilian University of Munich in a review article on climate therapy (DMW 2011).
So a holiday at the seaside will likely bring about some positive effects. But even at the most beautiful beaches, dangers lurk that can trigger allergic reactions.
The climate at the seaside is composed of humidity and temperature, UV rays, wind direction and atmospheric salinity. The temperature and humidity are mostly well balanced for the organism. Because the wind comes as a fresh breeze from the sea during the day and at night from the land, there is generally a lower level of allergens in the air.
However, house dust mite or mould allergies are not alleviated by spending time at the seaside, since the damp sea air is a good breeding ground for both these allergens.
In natural medicine, UV rays and the wind are believed to have a stimulating effect on the organism (Grifka 1995). But it is difficult to determine exactly how the many factors in the sea climate affect the organism. There are hardly any scientific studies on the individual aspects.
If the sky is blue and the temperature is high, a cool breeze often masks the intensity of UV rays. One to two out of 100 people in Central Europe experience polymorphous light eruption with prolonged exposure to sunlight; this is more commonly referred to as a sun allergy (Gambichler et al. 2009). Sunburn, solar dermatitis and worsening skin allergy symptoms can be prevented by using sunscreen and wearing long clothing. If you absolutely must sunbathe, it is safer to gradually increase your body’s exposure to the sun.
What’s that itch?
The waters are also impacted by climate change. The surface of the water is growing warmer, and the sea level and CO2 levels are rising slowly but steadily. The warm water provides good conditions for many parasites and bacteria to multiply.
If the skin comes into contact with them, allergic or inflammatory reactions can occur.
If itching only occurs on covered areas of the skin, such as under a swimming costume or diving suit, small jellyfish or sea anemone larvae may be the trigger. These tiny animals have vesicles filled with a toxin that is released on pressure. For someone surfing, the larvae are often crushed under the arms or the feet or the part of the torso lying on the board. The toxin can trigger itching while swimming or up to several hours afterward. Small raised, red dots appear, which look similar to flea or mosquito bites. This allergic skin reaction is also known as ‘sea bather’s eruption’ and was first described back in 1949. These reactions are usually harmless and disappear on their own within a few days.
Two Indian scientists published a summary of everything that can trigger skin reactions while bathing (Sridhar et Deo, Indian J Dermatol 2017). In their article, they described nearly 40 causes. Here are two examples of common triggers:
- Cercarial dermatitis, also known as swimmer’s itch: Cercariae are the larvae of flukes. They live in fresh water at temperatures over 20 degrees Celsius. The initial contact usually goes unnoticed. If antibodies are formed, the body reacts when cercariae penetrate the skin again and produces severe itching, redness and swelling (hives) at the point of entry. Since larvae rapidly die in the skin, the symptoms disappear after three to seven days. Specific treatment is not necessary.
- Contact dermatoses: Some people experience an allergic reaction to swimming equipment, such as swim goggles, fins, diving suits and nose clips that have been produced using a cure accelerator or plastic (such as diphenylthiourea or phenol formaldehyde resins).
Cortisone creams can help alleviate acute symptoms. The allergy triggering material should then be avoided in future.
Grifka J (Hrsg.) Naturheilverfahren. Urban&Schwarzenberg 1995
Kapitel 3.8 Klimatherapie, S. 90 ff.
Gambichler T, Al-Muhammadi R, Boms S. Immunologically mediated Photodermatoses. Am J Clin Dermatol 2009; 10: 169–80.
Zuberbier T. Shellfish Allergy. ECARF website, 2016