Hives, known medically as urticaria, are a very common problem They are sometimes known as ‘heat lumps’, appearing as raised’ red lumps which tend to come and go over any part of the body and which are extremely itchy. They are the result of increased capillary permeability, or ‘leaky bloodvessels’. The condition has been closely studied by allergists, dermatologists, pharmacologists, and immunologists. As a result the mechanism of action is reasonably well understood. It is thought that various processes, both allergic and non-allergic, lead to the release of certain chemicals, the most important of which is histamine. These chemicals influence the small blood vessels and capillaries of the skin, leading to skin changes which are characteristic of hives.

There are various known causes of hives (and probably as many unknown).

Infections. Parasitic infection, in particular various fungi, intestinal worms and hydatids, has frequently been associated with hives. So, also, have viral hepatitis and glandular fever in the presymptomatic stages. Similarly, upper respiratory tract infections may be accompanied by hives. Occasionally bacterial infections such as streptococcal or unsuspected focal dental or sinus infection may cause hives.

Physical causes. For instance the pressure of belts or shoes may cause localized hives (in this case called pressure urticaria), as may cold air, water or other cold substances. Heat may also cause localized hives if the heat source is local, or generalized urticaria if the condition is provoked by exercise. A still rarer form of hives, solar urticaria, is an allergy to different wave-lengths of ultraviolet light.

Internal disease. Very occasionally conditions such as lupus erythemaetosus, leukaemia, or cancer of some organ may cause hives. These can usually be excluded as possible causes by appropriate physical and blood examinations.

Psychological pressure. Emotional stress may either cause or aggravate hives. Whether emotional factors alone can produce these changes is uncertain. Before blaming ‘nerves’, the various other possible causes must be adequately excluded. Furthermore, treatment should be instituted to relieve the distressing appearance and itch, which only aggravate the stress. Adequate explanation and reassurance that the condition is self-limiting, must also be given to the patient.


Share and Enjoy:

Random Posts