[4][1] The injury may show small purple or black dots or staining of the skin from the natural dye inside the sea urchin.

[5] However, an allergic reaction or large enough dose of the toxins (such as puncture by > 15-20 spines) may lead to systemic effects such as nausea, vomiting, paraesthesia, generalized weakness, and respiratory distress.

[6] There are reports of accidental drowning due to the muscular paralysis, numbness, and disorientation caused by puncture from a flower urchin, but they remain difficult to confirm.

[7] Granulomas that happen to form near or within tendons, joints, or muscles may obstruct normal function of those structures, leading to chronic discomfort, movement deficits, or local inflammation.

[7][9][10] Other common remedies include salicylic acid paste, hot candle wax, vinegar, and urine, but evidence of their benefit remains unclear.