Drug eruption

General

A drug eruption is an undesirable allergic reaction of the skin and / or mucous membrane to the ingestion or topical application of a certain drug and is often an indication of a drug allergy.
Therefore, other organ systems in addition to the skin can also be affected by the body's reaction.

For more information, see the main Rash article.

Exanthem as an overreaction of the body

The root cause one Drug eruption is a side effect on a certain one drug.
In principle can any drug as triggers, with some active ingredients causing allergic reactions far more often than others.

A high risk for one Drug eruption contain, for example, the intake of:

• penicillin (up to 10% have a penicillin allergy) and others
• Antibiotics how Sulfonamides or Cephalosporins, also
• Thyroid hormones,
• some Painkiller (for example Naproxen or pyrazalone),
• Cardiovascular drugs (for example ACE-Inhibitors) or
• Immunoglobulins.

To the Overreaction of the body, it happens that the body's own defense system wrongly assesses a component of the drug as dangerous and therefore one Defense reaction initiates.

Please also read our page Medication rash.

Special case with Pfeiffer's glandular fever

The skin rash which is located under a Ampicillin-therapy if one is sick Pfeiffer's glandular fever (Mononucleosis) forms.

This represents no allergy in a narrow sense, why patients return when they are cured of the disease without hesitation Can take ampicillin.

Skin rash as the main symptom

The Leading symptom of a Drug eruption is the characteristic skin rash, this can be:

• small or
• large spots or
• lumpy.

In addition there is different shapesthat the rash can take on are some of the most common:

• photoallergic dermatitis,
• Contact dermatitis,
• Hives and Purpura.

Often the skin rash on the legs and arms and then gradually spreads to the upper body. The rash can be practical, however every part of the body manifest, but with an individual it will (without the reason being known) again and again at the same place or point to the same spots if an allergic reaction occurs again.

Neither that localization and that Appearance can provide a conclusion about the causative drug, only the point in time of its emergence allows association to take a certain medication.

Typically, the first symptoms appear between the 7th and 12th Day of treatment with the new drug. Once the body is sensitized and the active ingredient is taken again, so arise Exanthema usually within two days and are then more often associated with other systemic symptoms.

In some sufferers, the rash becomes pronounced itching accompanied. Except for the skin rash additional symptoms may occur, such as:

• Swelling of the mucous membrane in mouth or throat,
• Vomit,
• diarrhea or less often a reduced general condition with fever.

Other conditions associated with a rash, such as measles, scarlet fever, or rubella, are important differential diagnoses when a drug eruption is suspected.

diagnosis

If a drug eruption is suspected, a doctor should be consulted. However, its definitive diagnosis is often difficult for him for various reasons.

On the one hand, many sufferers do not even think about the fact that a new skin rash could be related to taking a new drug if it only forms days or even weeks afterwards. Even for a doctor, with the help of the medical history, it is often not possible to unequivocally assign the skin reaction to a specific drug.

Sometimes it is even more difficult that several new drugs were taken at the same time or that a viral disease was present at the same time, which could also have been the cause of the rash.

In addition, skin tests (the prick or patch test), which otherwise have a relatively high informative value in diagnosing allergies, often do not help here, since in many cases the drug eruption is only a so-called pseudo-allergy.

Renewed exposure to the suspected trigger can only be expected of the patient in rare cases, since one does not want to cause a risk of a severe second allergic reaction. In case of doubt, the doctor should issue the person concerned with an allergy pass that contains all active ingredients that could be used for the allergic reaction in order to prevent it from occurring again.

An allergic reaction or drug eruption should not be confused with the so-called Stevens-Johnson syndrome, a skin reaction also triggered by drugs. However, this is a serious disease with painful skin peeling and blistering.

Duration

Usually a drug eruption sounds within less days after stopping the drug again. No later than within a week should the complaints have passed.
Severe allergic reactions or even an anaphylactic shock, which is an acute circulatory failure, can take several weeks to recover.

therapy

The therapy one Drug eruption assumes the causative drug immediately discontinued becomes.

At need further treatment can be provided by a alternative Active ingredient be replaced. Further symptomatic treatment measures can also be used to alleviate the symptoms:

• To that itching counteracting will be common Antihistamines used, which curb the allergic reaction.
• Also cortisone is used in some cases.

This drug lowers that Immune reaction of the body and can in more severe cases either than Suppositories or infusion administered. Usually the drug eruption disappears within a few dayson its own after stopping the causative drug. In more severe cases, it sometimes takes time too few weeks.

Therape with cortisone

To relieve local discomfort you can Creams and Anoint with a high fat content and Cortisone be applied. Hydrocortisone is mostly used.

Cortisone inhibits the Inflammatory and immune response and improves the discomfort.
In the event of a very pronounced reaction or symptoms such as shortness of breath, shock or circulatory failure, cortisone is administered via the vein.

prophylaxis

The recurrence of a Drug eruption can be counteracted by using the triggering agent consistently avoids. This is especially important because a second reaction is usually one greater extent accept as the first.

Allergy type

The drug eruption is one type 4 allergic reaction.
In this reaction there is initially one Awareness of the person affected who has not yet developed a rash. This means that the first-time use of a drug sensitization of the immune system takes place, but there is still no rash.
In the next intake of the drug comes about 12-48 hours after taking to the drug eruption, which can look very different. Usually the drug eruption shows up in non-sensitized patients 9th day of taking.

However, an allergic reaction is not always the trigger for a drug eruption.