Sea urchins belong to a group of about 950 living species of spiny sea animals that are related to starfish and sand dollars. They often have calcium in their spines and may be mistaken for shells or rocks because of their appearance. Their spines are their defense mechanism. Read more: Can Sea Urchins Kill You? Article
Multimedia: Slideshows, Images & Quizzes
-
Healthy Aging: Causes of Muscle Weakness
From aging to illness, many things can cause your muscles to get weaker. Learn about the causes and what you can do to make it...
-
Picture of Tattoo Allergic Reaction
Tattoo Allergic Reaction. It is possible to have reactions to the inks or the metals in the needles used in tattoos, causing...
-
Picture of Contact with Sea Urchin
Contact with Sea urchin. Sea urchins don’t attack, but if you step on one or somehow get impaled by their spines, it can be...
-
Picture of Allergic Reaction to Lipstick Tattoo
Some people develop allergic reactions to tattoo pigments -- especially red pigments. See a picture of Lipstick Tattoo Allergic...
-
Picture of Photoallergic Reaction
An allergic reaction caused by drugs in which ultraviolet exposure changes the structure of the drug so that it is seen by the...
-
Healthy Eating: Best and Worst Seafood Dishes for Your Health
Seafood seems like a healthy choice. But the way it's cooked makes a difference. Find out about the best and worst seafood dishes...
QUESTION
What percentage of the human body is water? See AnswerRelated Disease Conditions
-
Cuts, Scrapes, and Puncture Wounds
Learn about first aid for cuts, scrapes (abrasions), and puncture wounds, when to see a doctor, if tetanus shots are necessary, and how to spot signs of infection.
-
What Are the 4 Types of Allergic Reactions?
Allergists recognize four types of allergic reactions: Type I or anaphylactic reactions, type II or cytotoxic reactions, type III or immunocomplex reactions and type IV or cell-mediated reactions.
-
How Long Does an Allergic Reaction Last?
Allergic reactions may last for varying lengths of time. They may take a few hours to a few days to disappear. If the exposure to the allergen continues, such as during a spring pollen season, allergic reactions may last for longer periods such as a few weeks to months.
-
Fatigue and Exhaustion
Fatigue can be described in various ways. Sometimes fatigue is described as feeling a lack of energy and motivation (both mental and physical). The causes of fatigue are generally related to a variety of conditions or diseases, for example, anemia, mono, medications, sleep problems, cancer, anxiety, heart disease, and drug abuse.Treatment of fatigue is generally directed toward the condition or disease that is causing the fatigue.
Treatment & Diagnosis
From 
Healthy Resources
Featured Centers
Health Solutions From Our Sponsors
Subscribe to MedicineNet's General Health Newsletter
By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.