Physical urticaria

In some individuals, urticarial weals are provoked by physical stimuli, e.g. friction (dermographism), heat or cold. Exercise may induce weals, particularly on the upper trunk (cholinergic urticaria). Physical urticarias may require combined Hj- and receptor receptor antagonists fully to block the vascular effects of histamine, which causes flushing and hypotension. Cyproheptadine is usually the preferred choice of Hj-antihistamine but causes drowsiness. 

Doeglas HMG (1975 b) Reactions to aspirin and food additives in patients with chronic urticaria, including the physical urticarias. Br J Dermatol 93 135-144 Doeglas HMG (1977) Dietary treatment of patients with chronic urticaria and intolerance to aspirin and food additives. Dermatologica 154 308-310 Doeglas HMG, Bleumink E (1975) Protease inhibitors in plasma of patients with chronic urticaria. Arch Dermatol 111 979-985... 

Urticarias resulting from non-chemical insults are classified as physical urticarias (see Chap. 21 by Henz). 

Physical urticaria is classified according to the nature of the eliciting stimulus, i.e., mechanical, thermal or electromagnetic (Table i). Rarely, urticaria has also been reported in association with decompression and with X-ray and argon laser treatment (reviewed in Henz et al. 1997). Cholinergic urticaria is often classified as physical urticaria since an increase in body heat is involved. Aquagenic urticaria is elicited by a chemical rather than a physical stimulus to the skin surface, with the water dissolving a water-soluble... 

Physical urticarias are not known to be induced by specific occupations, but they may become manifest in this setting. This holds particularly for professions requiring heavy mechanical work. Increased physical and sportive activities may also explain the higher frequency of manifest cholinergic and delayed pressure urticaria in men (Table 1). Severely affected persons... 

Table 1. Classification, clinical and diagnostic aspects of physical urticaria...

Table 2. Epidemiologic data on physical urticaria and occupational activities potentially affected...

Most types of physical urticaria share three common characteristics they can be repeatedly elicited by specific stimuli, the symptoms usually develop rapidly, and the lesions also disappear in a short time, with the skin again assuming a normal appearance. Exceptions to these rules are the delayed types of physical urticaria (Table 2). 

All patients with physical urticaria note itching at the site of whealing, although some experience stinging or burning instead. Deep swellings, particularly in areas where the skin cannot expand, such as at the hands and over joints, tend to be painful. In few... 

While the majority of wheals in physical urticaria develop rapidly and are of short duration, reactions can also appear with a delay of 2 h or even 4-8 h after stimulation. The most frequent representative of this group is delayed pressure urticaria, with lesions persisting for up to 3 days. 

The methodology of testing for physical urticaria is outlined in Table 1 and described below in more detail for each special type of physical urticaria. The presence of physical urticaria is easily missed when... 

As with other types of urticaria, effective treatment of physical urticaria requires an exact diagnosis. Underlying diseases must be treated in secondary types of physical urticaria caused by other diseases. Furthermore, the patient must be instructed to avoid the eliciting stimuli. This is particularly important when symptoms are intense or even life threatening. 

Since the majority of symptoms is due to histamine release, antihistamines almost invariably afford relief from itching and suppress whealing. In case of nonresponsiveness, other anti-inflammatory agents can be tried. Corticosteroids should be avoided because of the chronicity of the disease. In most types of physical urticaria, a refractory period is observed which can be used to induce temporary tolerance. 

Patients with this type of physical urticaria develop deep wheals in skin regions exposed to high pressure. 

Cold urticaria is defined as urticaria or angioedema on exposure to cold. Lesions can be provoked through contact with firm cold bodies, cold fluid, cold air via a chilling effect and, sometimes, by lowering of the body core temperature. In 96% of patients with cold urticaria, the disease is idiopathic. Compared with other forms of physical urticaria, it... 

Doeglas HMG (1975) Reaction to aspirin and food additives in patients with chronic urticaria, including the physical urticarias. Br J Dermatol 110 382-388... 

Physical urticaria. Physical urticarias are characterised by the appearance of wheals or angio-oedematous manifestations after physical stimulation. Frequently, different forms of physical urticaria may coexist in the same subject, and they often spontaneously recover (especially from the acquired forms). Occupational physical factors, e.g. low or high temperatures, etc., can thus trigger recurrence of the symptoms. 

Dermographic urticaria is the most frequent form of physical urticaria, and it is characterised by the development of wheals in those sites exposed to even mild traumas (scratching, rubbing, etc.). Moreover, a typical dermographic reaction is present in the case of mastocytosis, even in the absence of apparent skin lesions. 

Rudzki E, Rebandel P, Grzywa Z (1989) Patch tests with occupational contactants in nurses, doctors and dentists. Contact Dermatitis 20 247-250 Scheman AJ, Katta R (1997) Photographic allergens an update. Contact Dermatitis 37 130 Torresani C, Periti I, Beski L (1996) Contact urticaria syndrome from formaldehyde with multiple physical urticaria. Contact Dermatitis 35 174-175... 

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