Physical urticaria is a distinct subgroup of the

urticaria Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Hives may burn or sting. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasti ...

that are induced by an exogenous physical stimulus rather than occurring spontaneously. There are seven subcategories that are recognized as independent diseases. Physical urticaria is known to be painful, itchy and physically unappealing; it can recur for months to years of a person's life.

Signs and symptoms

Urticaria are characterized by dermal

edema Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's Tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels t ...

(wheal, swollen) and

erythema Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not assoc ...

(flare, red), also known as hives. Hive lesions typically last less than 24 hours and are usually

itch Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

y (pruritic). Hives can appear anywhere on the body and they may change shape, move around, disappear and reappear over short periods of time.

Types of hives

Acute urticaria (short-term): can develop suddenly and will last ''less'' than 6 weeks. About 1 in 6 people will have acute hives at one point in their life. Chronic urticaria (long-term): can develop suddenly and will persist ''more'' than 6 weeks. This type of urticaria is uncommon and occurs in only 0.1% of the population. 20% of people with chronic urticaria report still having problems 10 years after its onset.

Causes

The cause of physical urticaria is unknown but it has been suggested to be an

autoimmune In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". P ...

disease. Suggesting that antibodies, which are produced by the immune system to protect humans from foreign microbes, are binding to body tissue; damaging body tissue. In some cases physical urticaria can be a symptom of an underlying health issue such as:Grattan C, Black AK. Urticaria and angioedema. In: Bolognia JL, Jorrizo JL, Rapini RP, editors. Dermatology. Vol. 1. London: Elsevier, 2003: 287–302 *

Thyroid disease Thyroid disease is a medical condition that affects the function of the thyroid gland. The thyroid gland is located at the front of the neck and produces thyroid hormones that travel through the blood to help regulate many other organs, meaning t ...

Hepatitis Hepatitis is inflammation of the liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pa ...

Infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

Cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

Food allergies A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure ...

Atopy Atopy is the tendency to produce an exaggerated immunoglobulin E (IgE) immune response to otherwise harmless substances in the environment. Allergic diseases are clinical manifestations of such inappropriate, atopic responses. Atopy may have a ...

Diagnosis

Sub-categories

There are seven sub-categories of physical urticaria: * delayed pressure urticaria (DPU) *

cholinergic Cholinergic agents are compounds which mimic the action of acetylcholine and/or butyrylcholine. In general, the word "choline" describes the various quaternary ammonium salts containing the ''N'',''N'',''N''-trimethylethanolammonium cation. F ...

urticaria (ChU) *

cold urticaria Cold urticaria (essentially meaning cold hives) is a disorder in large red welts called hives (''urticaria'') form on the skin after exposure to a cold stimulus. The hives are usually itchy and often the hands and feet will become itchy and swoll ...

(CU) *

solar urticaria Solar urticaria (SU) is a rare condition in which exposure to ultraviolet or UV radiation, or sometimes even visible light, induces a case of urticaria or hives that can appear in both covered and uncovered areas of the skin. It is classified as a ...

(SU) * Acute pressure urticaria (AU) * chronic idiopathic urticaria (CIU) * symptomatic dermatographism urticaria (SDU) (most common)

Treatment

Antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provides re ...

agents are the typically prescribed drug for the treatment of physical urticaria. They block the effect of histamine, a compound produced by the body which forms a part of the local immune response consequently causing inflammation. Some research has suggested that the use antihistamines and

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

in synergy are better for the treatment of physical urticarias. The cascade of events that link the autoantibody-antigen reaction with the production and release of histamine is not well characterized. Therefore, the focus of treatment for physical urticaria has been on characterizing the effectiveness of antihistamines rather than analysis of receptor binding or the pathomechanisms.

References

{{Urticaria and erythema Urticaria and angioedema Dermatologic terminology