Forms of Urticaria
Speaking urticaria is similar to speaking of headaches: both causes and forms vary greatly. The spectrum ranges from short-lasting, mild discomfort to years of constant torment and from clear, easily avoidable triggers to (not so few) cases in which the cause is never found. Also, it is not always easy to identify boundaries between urticaria and other diseases. Some forms of allergies look very much like urticaria, and the processes in the immune system and the body are also partly the same, but also partly very different from the processes observed, for example, in connection with asthma, hay fever, or classic food allergies.
The many different clinical pictures of urticaria can be divided according to their duration into acute (less than 6 weeks) and chronic (more than 6 weeks) and into three major groups according to their course:
- the spontaneous urticaria
- the physical urticaria and
- the group of other types
The forms of spontaneous urticaria
- Acute spontaneous urticaria: Hives or angioedemata are formed and fade away after hours or days—at the latest after six weeks.
- Chronic spontaneous urticaria: Hives or angioedemata are formed; the symptoms persist for more than six weeks.
Subforms of physical urticaria are:
- Urticaria factitia: Rubbing, scratching, or scrubbing the skin.
- Cold urticaria: Contact between the skin and cold.
- Heat urticaria: Contact between the skin and warmth/heat.
- Solar urticaria: UV light or sunlight
- Pressure urticaria: Pressure
- Vibration urticaria / vibratory angioedema: Vibrations
Other forms are
- Aquagenic urticaria: Contact between the skin and water.
- Cholinergic urticaria: Raised temperatures (for example due to hot baths).
- Contact urticaria: Contact between the skin and certain substances.
- Exercise-induced urticaria/anaphylaxis: Physical strain.
What is spontaneous urticaria and why do we distinguish between acute and chronic urticaria?
In spontaneous urticaria, wheals and other discomfort occur “out of the blue”, i.e., affected patients cannot predict when the next attack of their disease will occur and they cannot usually consciously trigger such an attack. In spontaneous urticaria every part of the body can be affected.
In acute urticaria, the most common subtype overall, there is a maximum of 6 weeks of discomfort, i.e., acute urticaria disappears within a few days to weeks after the first appearance of hives or swelling of deep skin (often just as inexplicably as it has come). In most cases of acute hives there is a one-time attack that can often cause great anxiety—not least because the symptoms have been completely unknown to those affected up to this time.
Chronic urticaria, i.e., spontaneous urticaria lasting more than six weeks, is very much rarer than acute urticaria.