STINGS: HYDROIDS

In the case we previously presented, a hydroid sting may have been the culprit that resulted in serious infection. Let’s take a closer look at hydroids, what they are and how stings should be managed

WHAT ARE HYDROIDS?

Hydroids look like plants, seaweed or clumps of feathers. Like their relatives, fire corals and jellyfish, these animals have tiny stinging cells known as nematocysts. As in the aforementioned case, the stinging nematocysts may also fire into the skin of unsuspecting divers, which typically results in a cluster of red welts and bumps that burn and itch.

The severity of symptoms of envenomation depends on:

• the hydroid species;

• venom dose; and

• body location.

SIGNIFICANT ENVENOMATIONS

Hydroid stings producing symptoms such as nausea, vomiting, shortness of breath or confusion are considered significant. Susceptible individuals can develop an allergic reaction, which may be severe. Anaphylaxis is a potentially deadly allergic reaction that can involve respiratory distress, airway compromise and other unstable vital signs. Anyone suspected of having a serious allergic reaction should quickly seek medical care.

TREATMENT

There is no consensus for the treatment of a hydroid sting as different species may react differently to various first aid procedures, including the application of vinegar and heat.

In general, it appears sensible to: • Rinse the skin immediately

with seawater. Try to refrain from rubbing the area, as this may induce further nematocyst discharge.

Pain can be treated with the local application of heat or cold or by analgesics if necessary.

Once cleaned, topical steroids such as hydrocortisone and antihistamines are commonly employed to reduce local skin irritation and itching.

ABOVE LEFT Aglaopheniacupressina, also known as fireweed, has a powerful sting and should be avoided

ABOVE RIGHT A hydroid sting typically appears as a cluster of red welts and bumps that burn and itch