Management of allergy, rashes and itching

Chapter 12 Management of allergy, rashes and itching





Introduction


The vast majority of skin problems that present in the community are minor in nature. Unfortunately, very occasionally, the development of seemingly innocuous symptoms such as a rash and/or itching can be the presenting symptoms of a life-threatening condition – namely anaphylaxis or meningococcal septicaemia. Whilst other clinical conditions can mimic both anaphylaxis and meningitis, especially in the early stages, there are usually clues in the presentation that help to minimise the delays in administering appropriate therapy. It is not possible in this chapter to cover all potential causes of a skin rash and/or itching. Rather, this chapter aims to focus on important conditions that require recognition, treatment and possible referral in the acute pre-hospital setting. The objectives of this chapter are listed in Box 12.1.





Primary survey


Assess for an ABC problem in patients with itching and/or a rash (Box 12.2). The recognition of developing airway obstruction is critical, particularly in the presence of anaphylaxis. Patients may complain initially of a feeling of tightening in the throat, be unable to complete sentences or have audible airway noise (stridor or wheeze). If airway obstruction becomes complete, then prompt initiation of a surgical airway will be required.





Secondary survey (including history taking)


Having ensured that your patient has no immediately life-threatening problems on their primary survey or the need for immediate hospital admission, you will be left with a patient for whom a careful history and examination should elucidate whether further treatment is required and whether or not the patient can be safely left at home. A history of the presenting complaint should be taken, any other information noted and an examination performed as described earlier in this series. Remember that the skin is the largest organ in the body and adequate exposure may be required to allow a thorough examination to be completed. Obviously, the degree of exposure will be dictated by the prevailing circumstances and nature of the presenting complaint(s).



History


The following will be helpful in establishing the diagnosis in someone presenting with a rash or itching. Unfortunately, there are few clinical tests that can help in the diagnostic process, which relies heavily on the use of a logical process to identify and eliminate serious problems.









Past medical history/drug history


Any past history of similar events should be noted. Many drugs can be implicated in the development of allergic reactions and anaphylaxis. Aspirin accounts for about 3% of anaphylactic reactions and symptoms may occur hours after ingestion.5 Those allergic to aspirin may also be sensitive to NSAIDs, which may cause a similar reaction. A similar allergic relationship can occur with penicillins and cephalosporins. Even people who have had no previous problems with penicillins may experience an anaphylactoid reaction after taking them. Diabetics are at a higher risk of cellulitis.




Examination


See Chapter 2 relating to patient examination. It is always advisable to check and document the vital signs of any patient who presents with a possible allergic reaction or rash. This includes the measurement of temperature, pulse, blood pressure and respiratory rate. An elevated temperature and/or the presence of enlarged (and often painful) lymph glands in the submandibular and/or cervical regions suggests the possibility of an infective process. It is sensible to test for neck stiffness in any patient who presents with a rash and systemic upset. The patient’s neck should be passively flexed forwards towards the chest wall, a manoeuvre that should not be painful to complete. If neck flexion causes pain, then Kernig’s and Brudzinski’s signs should be tested:







Examination of the skin


As previously mentioned, it is important to ensure adequate exposure of the skin, especially in younger children who may be less able or likely to bring the presence of a rash to your attention. In a significant proportion of patients with meningococcal septicaemia, the rash starts on the palms of the hands and/or the soles of the feet so be sure to examine these carefully. Is the rash painful to the touch? Document any swelling of the tissues, especially around the face and the eyes. Gently examine inside the mouth looking for swelling of the tongue. Note the presence of any scratch marks on the body. Note the colour associated with any rash – does the rash disappear or change colour when pressure is applied? (Ideally this should be done with the base of a clear glass.) Table 12.3 lists the common terms used to describe physical changes in the skin associated with the presence of a rash.


Table 12.3 Terms used to describe rash-induced skin changes



























Terminology Description Clinical examples
Macular Non-infiltrated flat lesions which differ in colour from adjacent areas of skin Erythema, purpura
Papular Well demarcated raised lesions in the skin of varying sizes Urticarial wheals, planar warts
Vesicular Small protuberances with a central cavity containing clear liquid Chickenpox
Excoriations Very superficial wounds in the surface of the skin Scratches
Purpura Small patches of non-blanching discolouration caused by bleeding from small superficial blood vessels in the skin Petechiae – Small spots of purpura Ecchymoses – Large confluent patches of purpura Meningococcal disease Idiopathic thrombocytopaenic purpura (ITP) Henoch–Schonlein purpura (HSP)





Management plan


Depending on the suspected diagnosis and clinical condition of the patient, the usual management plan can be summarised as one of the following five choices:







Where indicated, appropriate home management options are discussed for each condition.


Jun 14, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Management of allergy, rashes and itching

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