Practitioner April 2010 – 254 (1728):40-41

Allergic reactions

15 Apr 2010


Dr Nigel Stollery MB BS DPD

GP, Kibworth, Leicestershire and clinical assistant in dermatology, Leicester Royal Infirmary


Granulomatous cheilitis

Granulomatous cheilitis is an uncommon condition in which the lips become swollen. There are many different causes including allergy, Crohn's disease, infections, malignancy and sarcoidosis. It generally first occurs in early adulthood. The initial onset is usually sudden and settles within hours. However, with each recurrence the swelling tends to last longer and may become permanent. The lips have a rubbery texture and may crack and feel sore. When the condition is related to an allergy the causative agent needs to be avoided. In other cases (e.g. Crohn's disease) it is important to treat the underlying disease. Granulomatous cheilitis can be treated with steroids, both topically and injected into the lips, non steroidals, sulfasalzine and mast cell stabilisers. In extreme cases surgical debulking procedures may be considered.

Lanolin allergy

When eczema fails to respond to standard treatment regimens of emollients and steroids, there may be a number of possible reasons. A common one is the presence of infection which can be treated with antibiotics. However, a less common cause is a sensitivity/allergy to the treatments themselves. If this is suspected patch testing can be used to confirm which components of the product are responsible. In this case it was the lanolin present in the emollient.


Polymorphous light eruption

There are many skin conditions associated with exposure to light. Distinguishing between the photodermatoses can be a challenge so a detailed history is very important. Polymorphous light eruption (PMLE) or sun allergy is the most common of the acquired photodermatoses affecting 10-15% of people at some time during their lives. Typically, PMLE occurs on some, but not all, sun-exposed areas as an itchy papular rash which develops within hours of sun exposure and may last for up to 10 days. Treatment options include modifying exposure to UV light, e.g. by using sunscreens, and the use of potent topical or oral steroids. In severe cases, UV desensitisation each spring can be helpful.


Drug allergy

Drug reactions are common especially with penicillins and sulphonamides. The rash is often morbilliform in appearance starting on the trunk. Diagnosis can be difficult especially when the rash does not develop until days after the drug is first taken. Care is needed as in extreme cases drug reactions may cause anaphylactic reactions, which may be life threatening. However, many people mistakenly think they have an allergy to an antibiotic, having been told so in childhood when they developed a rash. In such cases, the rash may be a viral exanthema caused by the underlying illness.


Latex allergy

Latex is the milky fluid derived from lactiferous cells of the rubber tree Hevea brasiliensis. It is a complex material from which more than 200 polypeptides have been isolated. Any one of these polypeptides may be a potential allergen. Latex is commonly found in everyday items e.g. condoms, erasers, tyres and balloons and products used by healthcare professionals such as gloves and catheters. Latex allergy is diagnosed using prick, rather than patch, testing. Sufferers from latex allergy need to be careful to avoid contact with the allergen by using latex-free products e.g. gloves where possible.


Contact dermatitis

The mechanism responsible for the rash of contact dermatitis is a delayed type IV hypersensitivity reaction. Characteristic features include reaction in all areas of the skin in contact with the allergen, sensitisation which persists indefinitely and specificity to one allergen or its close relatives. Nickel is one of the most common causes of contact dermatitis. It is used in cheap jewellery, buttons, keys and clothing fastenings such as jeans studs. In this case a bra fastening was the culprit. If the cause is in doubt patch testing should be carried out.