Pruritis

Carl Edmonds feels that this is a common manifestation of diving in a compression chamber, most likely due to the release of small bubbles from gas dissolved in the epidermis. In this mild form, no signs are visible, and the itching is temporary, mild, comes and goes and is more marked around the ears, wrists and hands. He does not consider this a systemic manifestation of decompression sickness.

Similar cases of itching, burning, increased heat and visible rashes occur after many dives and clear spontaneously or with 100% oxygen and aspirin and probably should not be recompressed. However, there have been recent reports of an association with skin bends with patent foramen ovale [UKSDMC] and there are now recommendations that divers with this condition be checked for PFO.

Patchy erythema (Cutis Marmorata)

Patchy, reddish-purple mottled areas can occur, especially around the shoulders and trunk. These are intensely pruritic and are due to a local vascular reaction from bubbles in the tissues below the dermis. This has a more serious connotation and is thought of as a systemic manifestation of decompression sickness and is often associated with other more serious types of DCS, such as chokes. All of these divers should be treated with recompression.

Lymphatic Obstruction

Blockage of the dermal and subcuticular lymphatics with bubbles usually results in edema and a peculiar pitting of the skin called peau d’orange (French, meaning skin of the orange, or, orange-peeling). This is pigskin appearance more often seen over the trunk of the body and again is evidence of a more serious form of DCS.

References:

Edmonds, et al: Medical Aspects of Diving, The Medical Journal Of Australia; 1972, 2:1199-1416