If discomfort from a lingering rash remains sharp and throbbing despite antihistamines, what issue does this suggest?

A deeper mechanical issue like an embedded particle or developing localized infection

Monitoring the effect of over-the-counter antihistamines provides a useful self-assessment tool for determining the nature of persistent irritation following marine contact. If a standard oral antihistamine provides temporary, noticeable relief from itching, it strongly indicates that the underlying process has a significant inflammatory or allergic component, suggesting hypersensitivity that needs time to resolve. Conversely, if the discomfort persists and the sensation is described as sharp, throbbing, or actively worsening even when antihistamines are utilized, this pattern shifts the concern away from a simple hypersensitivity reaction. Such symptoms point toward a more structural problem, such as a fragment of coral or other debris embedded deep within the dermis acting as a foreign body, or the early stages of a localized bacterial infection, both of which necessitate a completely different treatment path focused on removal or antibiotic clearance rather than just dampening immune signaling.