Hives or urticaria is red itchy spots that appear on the skin, their bump-like appearance being the reason for the given name. They usually occur when a person develops an allergy to a drug, insect sting or food item. Infections or stress may also lead to the condition due to the release of certain chemicals such as histamine or mast in the body. Histamine is released when the body is in contact with toxins or pollen. This is a common condition that usually occurs in individuals who are more prone to allergies.
Normally hives lasts about one to two days and in this duration it may change rapidly in size and location by the hour. It may appear to have completed receded, only to quickly reappear in another spot. Hives may be accompanied by a deeper swelling known as angioedema and may also appear in mucous membranes, the eyes and lips.
Chronic urticaria lasts about six weeks and in about 80% of the cases cannot be traced to any allergic reaction. Urticaria may cause difficulty in breathing and shock but this occurs only in rare cases and hives hardly leads to life threatening situations. Hives affects 15 to 20% of the population at some time in the course of their lives. Acute hives in children may be caused due to a viral infection.
It is said that having hives may lead to stress, but stress does not lead to hives. However some studies show that emotional stress may cause hives, as do extreme hot or cold weather conditions. Chronic stress and tension may cause hives, so it is important to find ways to relax and take some time off your normal routine. Stress affects the immune system and may indirectly lead to hives especially when it persists for a long period of time. Stress is known to affect the hormonal balance and the body chemistry leading to hives.
Hives usually recedes by itself without any serious implications. In severe conditions, drugs or injections may be prescribed. Only in rare cases where a swelling blocks the airway and prevents the person from breathing properly, would it be described as an emergency.
Pruritus is a skin disease associated with conditions pertaining to autoimmune disorders and other advanced complications like liver cirrhosis. Pruritus cases vary from mild to complex as the symptoms associated with the condition generally aggravate with age. Untreated pruritus can be a big hindrance to an individual's normal life as it interferes with sleep patterns leading to irritability and stress. In some cases the causative agent for this disease is the Hepatitis C virus which accounts in 20% of the population.
Pruritus occurs mostly in the wrist and ankles as a scratch. The intensity of the itch facilitates other factors such as eczema, impetigo and induced urticaria. The immune response releases histamines causing allergic reactions. The association of pruritus with allergic reactions is identified by the presence of serotonin. The serotonin release caused because of pruritus occurs in case of preexisting medical conditions such as polycythemia, lymphoma and cholestasis.
The identification and diagnosis of pruritus is closely associated with the evaluation of dermatological condition of the patient. Progressive pruritus is noticed with contact dermatitis, urticaria, scabies, pediculous infections of the genital region, folliculitis and xerotic eczema.The factors associated with the respective causes along with pruritus are fomites, dust, bites, chemicals and photosensitivity. Atopic dermatitis induces aggressive form of pruritus. The intense forms of atopic dermatitis associated pruritus usually occur in pregnant women, infants and veterans. Systemic causes of pruritus involve preexisting conditions such as Hodgkin's lymphoma, HIV, scleroderma, multiple myeloma, chronic renal failure and many other conditions.
Pruritus diagnosis involves meticulous procedures in examining the exact history of the patient to rule out other forms of allergic reactions. The information pertaining to the patient history includes several factors such as travel zones, food and occupation. Differentiation of non-septic and septic forms is done to identify systemic involvement of the disease. Secondary infections and malignancies associated have to be identified. Specific sites are identified on the skin reaction to respective drug therapy is carefully monitored.
Avoid stress which delays the healing process. Topical creams are prescribed for allergic forms of pruritus. Skin cleansing is an important step. It is predominantly done to prevent secondary infections and conditions such as psoriasis. Patients who have history of sunburn and sensitivity to extreme temperatures need to relieve the stress upon immune system that reacts immediately to such conditions. Hydration of the skin helps in the restoration of the skin cells to facilitate the process of healing. Change of diet and lifestyle is prescribed to patients who are sensitive foods such as nuts, seafood etc. Patients with a history of contact dermatitis are advised to use skin safe deodorants, shampoos and bubble bath solutions. Oral antihistamines are recommended to ease the immune system's reactivity. Hot water bath and tight clothing are to be avoided in case of pruritus as it may aggravate the condition. Topical creams containing corticosteroids are recommended during the onset of a pruritic reaction. In case of secondary infections associated with pruritus, antibiotics are given.
Anaphylaxis is a hypersensitive reaction due to contact through allergens. These allergens induce an immediate immune response that is life threatening in most occasions. Anaphylactic reactions produce various clinical symptoms such as urticaria, respiratory congestion and gastrointestinal disturbances. Anaphylactic response is caused by certain type of compounds which may include proteins, pollen, venom, hormones and also some food extracts. The immunoglobulin E or IgE is responsible for the onset of anaphylactic reaction when exposed to an allergen.
Mechanism of anaphylactic reaction
A series of reactions take place in the body when anaphylaxis is triggered. The IgE which has a half-life of two days, binds to the fragment crystallizable or FC receptor part of the basophils and mast cells. This process is activated when the person comes in contact with an allergen which in turn mediates cellular de granulation and their release of biogenic amines such as histamine and serotonin. The effects of these biogenic amines may include the smooth muscles which generally constrict at the bronchiolar region and broncho capillary venules. It also causes the arteriole dilation.
Anaphylactic responses are of different types and are associated with allergen sources of different kinds such as pollen, food, insects and also some drugs. It happens because of the antigen contact to which the patient had been previously exposed. This type of antigen is also called an allergen. Systemic anaphylaxis is a serious condition in which the mast cells of the connective tissue become activated resulting in dangerous effects such as airway obstruction, swelling of the epiglottis and ultimately suffocation. Systemic anaphylaxis proceeds into another condition called anaphylactic shock which happens because of suffocation induced by the respective allergen. In addition to these, anaphylaxis may also result because of extreme physical exercise. This condition is also called exercise induced urticaria. Allergies to food like eggs and milk are common among infants. Other than these, underlying conditions such as hay fever, asthma and eczema may also induce anaphylaxis if untreated.
Anaphylactic shock is widely reported in people after consuming foods such as peanuts and Brazil nuts. Such food products induce the anaphylactic reaction in an instant causing severe discomfort and sometimes death. Many people also experience anaphylactic reactions because of penicillin administration. Some reactions of anaphylaxis also include excess production of mucous in the mouth, nose and throat. Atopic patients are highly susceptible to anaphylaxis. Patients having an underlying atopic condition produce high amount of IgE antibodies and hence they must be monitored carefully.
Diagnosis of Anaphylaxis
Anaphylactic reaction is diagnosed based on clinical symptoms such as skin rash (insect bites), hoarse voice, chest congestion, breathing difficulty, diarrhea, vomiting and abdominal cramps. Identification of the source is the predominant factor in the diagnosis of anaphylactic reactions. Thorough examination of the cause with immediate life saving measures must be done. Anaphylaxis can be fatal if not managed properly.
Avoid foods that induce the condition. In the case of anaphylactic reaction, medical attention must be sought immediately. Oral medications such as Benadryl or diphenhydramine are given. EpiPen or injectable epinephrine is the drug of choice to control the anaphylactic reaction. Intravenous antihistamine drugs and oral steroids are given for a period of time to prevent the reoccurrence of the anaphylactic reactions.
Bibliography / Reference
Collection of Pages - Last revised Date: February 16, 2019