Hives (known medically as urticaria) are smooth, raised, red, pink or white bumps of varying sizes that can appear suddenly anywhere on the body. Hives are a sign that the whole body is experiencing a hypersensitivity reaction. Fluid escaping from blood vessels becomes trapped in parts of the skin and lining membranes of the body, causing localized swelling.
Hives can occur anywhere on the body where there is skin. Therefore, you can also get hives inside your throat. These can be very dangerous as your breathing can be obstructed by these hives.
Hives can be caused by classic allergic reactions in which histamine triggers an inflammatory response. It can also be caused by a number of other regulatory systems in the body in response to different types of triggers.
Having had hives myself, I can say that the rapid appearance can be quite alarming. The hives themselves can also be quite pronounced. Allergic hives can appear in minutes and in some cases hives can appear in seconds.
The most common allergic triggers fall in 5 categories:
- drugs, especially antibiotics;
- foods, especially fish, shellfish, nuts, peanuts, eggs, berries and food additives;
- insect bites or stings;
- inhalant allergens, such as animal danders, pollens and molds;
- contact allergens which can include chemicals, plant substances, skin creams, cat scratches, moth scales or even animal saliva.
Hives usually last a few hours or a day and go away on their own. However, episodes can continue for varying periods of time.
There are two kinds of hives:
- Allergic urticaria, which we've discussed. These are caused by the body's allergic reaction to substances it encounters.
- Non-allergic urticaria. These are caused by factors other than an allergic reaction.
The best treatment option for hives is to identify and remove the cause. Medications, such as antihistamines, may be recommended to relieve symptoms only if it can be determined that the hives are caused by allergy. In cases where hives are not related to allergy, the removal of the cause can be much more difficult.
There are some common triggers for hives. While it varies from individuals, these may include:
- Allergens (e.g., foods, pollens, animals, insect stings).
- Irritants (e.g., cosmetics)
- Autoimmune diseases
- Other factors (e.g. extremes in temperatures, sunlight, tight-fitting clothing, etc.)