By Dr Gary Morris

The Story of a Rash after a Dive


The Incident

The diving and visibility had been good and the filming of marine ecosystems was progressing well, but deadlines had to be met, so the film crew took every opportunity to get their required shots. For the previous 10 days, diving had taken place with two or three dives daily, each lasting 45 to 60 minutes. Diving depths were up to 20 m with a lot of variation in depth; divers were ascending to get a better view and then descending to assist with another aspect of the work. This required a lot of physical effort. The divers were experienced, having done numerous dives in many locations around the world. The area where they were diving, on the coast of South Africa, was very familiar and they knew the conditions. Some of the divers on the team had been ill and could not dive, so the other team members were working harder to get things done. They were fit and healthy, but starting to tire after this intense period of work. The first dive of this particular day (when the incident occurred) was to a maximum of 18 m and lasted about an hour. The day was beautifully calm and warm.  The divers surfaced and one of the most experienced in the group felt pain in her right shoulder on removing her wetsuit. She developed itching, swelling, mottling and a purple-red discolouration of the skin on her upper arm. Other than that, she felt well and had no tingling in her hands or feet, no weakness, no headache or confusion, and she did not feel breathless. She was given oxygen for about 30 minutes and one hour after surfacing, the symptoms had markedly decreased.

The Diagnosis

The diver and her companions suspected decompression illness (DCI) and contacted the DAN Hotline. They were advised to see a local diving doctor to treat possible skin bends (cutaneous decompression sickness). They reached the doctor’s rooms about two hours after surfacing. By that time the symptoms had almost disappeared, although mild pain persisted in her upper arm. There was still slight swelling, mottling and redness of her upper arm. Her shoulder was mildly tender, but had its full range of movement. No neurological, chest, heart or other abnormalities were found. A diagnosis of Type 1, pain- only DCI with skin involvement was made. As the symptoms had mostly resolved and there were no signs of neurological involvement (Type 2 DCI), she was treated with a further hour of surface oxygen and given aspirin for the pain. She went home to rest with the instructions to ensure adequate fluid intake and to contact the doctor if any other symptoms developed. She was not permitted to dive for the next seven days. The mild pain and rash persisted for a few days, after which she returned to active diving free of symptoms.

What is “Skin Bends”?

Skin problems in diving can have various causes, including DCI, but rashes and itchiness can also be caused by stings from jellyfishes, bluebottles, coral and the spines of sea urchins and various fishes. Suit squeeze or an allergic reaction to the neoprene in wetsuits will cause a rash, pain or itchiness in a pattern resembling the folds and seams of the suit.  DCI with skin manifestations can vary from mild swelling and itching confined to a small area, to more widespread and dangerous rashes and mottling that could signal a more serious underlying problem.

Itchiness with no rash

There are many causes for itchy skin after diving. However, when this occurs after chamber or dry suit diving, it may be due to a highly localised form of decompression sickness (DCS). This type is not associated with other systemic manifestations. It is probably due to gas passing into the skin from the high pressure gas surrounding it. The cause of the itch is thought to be the formation of small bubbles in the epidermis with the release of pressure. The symptoms are mild and the itching only temporary.  No signs are visible on the skin. The areas most affected are the forearms, wrists, hands, nose and ears. No treatment is needed.

Scarlatiniform rash

This presents as a flat, itchy rash, mainly over the chest, back, shoulders or thighs. The rash appears similar to sunburn. It is also caused by bubble formation in the skin, with the release of histamine and other chemicals. The rash is not associated with any other manifestations of DCI, apart from pain. It clears with oxygen treatment or spontaneously in a few hours. Recompression is usually not needed unless the rash progresses to the more serious form or neurological symptoms develop.

Marbling of the skin

This serious form of skin bends, known as cutis marmorata, looks mottled with various shades of bright red, purple or even blue skin, with an uneven, marble-like pattern. Swelling occurs and the skin takes on an “orange-peel” appearance. The skin can be very itchy and irritated at first. It is also most common on the torso, shoulders and thighs. The discolouration may appear in patches or in severe cases may begin on the chest and spread downwards. The signs on the skin indicate what is happening elsewhere in the body; gas bubbles are found in the skin, underlying tissue and blood vessels. This is a serious condition and is usually found in conjunction with neurological DCI. A diver with this condition requires recompression.

The Significance of Skin Bends

Skin bends can indicate underlying or developing serious decompression problems

Cutaneous DCS symptoms have been known to manifest before or along with the symptoms of more serious types of DCS, such as neurological DCS. The sooner a diver gets help, the greater the chances of a full recovery. Recognising a skin bend may be the first step to timeous and effective treatment.

Skin bends may indicate a patent foramen ovale

A patent foramen ovale (PFO) is a heart condition that is thought to increase the risk of serious DCI. There appears to be a correlation between skin bends from dives well within the recreational dive tables and the presence of a PFO. Divers who have a history of unjustified skin bends are advised to seek the opinion of a diving doctor.

What to do when you think you have a skin bend

Whether the cause of a skin bend is the depth or the duration of the dive, symptoms usually appear within a few minutes to a few hours after surfacing. If a diver develops a problem with his or her skin after a dive, follow the rule: it is a bend until proven otherwise. When a skin bend is suspected, the following should be done:

  • Give the diver oxygen by mask.
  • Note the distribution of symptoms, the time of onset and the progress of the rash.
  • Note the response to oxygen and the development of any other symptoms.
  • Contact the DAN Hotline to discuss the symptoms and how to proceed.