Drug eruptions

What is a drug? eruption?

Acute or subacute adverse cutaneous Reactions to a drug or medication include drugs rashes.

There are many types of drug rash, ranging from mild and unnoticed. eruption to a severe skin adverse reaction (SCAR) that can be deadly.

The most common drug eruptions are:

• Morbid or exanthematous drug rash
• Urticaria me angioedema (which rarely leads to anaphylaxis)

SCARs are rare:

• Drug hypersensitivity syndrome

• Stevens-Johnson syndrome / toxic epidermal necrolysis (SJS / TEN).

There are many other cutaneous Adverse reactions even:

• Acute generalized exanthematous pustulosis (AGEP) (pustular similar to psoriasis)

• Serum disease (urticaria, fever, arthralgia, lymphadenopathy)

• Hypersensitivity vasculitis (palpable purple)

• Fixed drug eruption (single or multiple recurrent blisters plates)

• Lichenoid drug rash (lichen planus-like reaction)

• Drug induced photosensitivity: phototoxicity (exaggerated sunburn) or photoallergy (eczema in places exposed to the sun)

• Bullous drug rashes (it is important to recognize immune disease, as drug withdrawal leads to elimination)

• Drug-induced lupus erythematosus.

Sometimes a drug rash is unnecessarily called a skin rash.

Drugs can also cause:

• Drug-induced skin pigmentation
• A skin problem that is not normally caused by a medicine (for example, psoriasis caused by lithium, eczema caused by retinoids)
• Systemic Contact dermatitis

• Allergic contact dermatitis and photocontact dermatitis.

• Hair hair loss or increase (hypertrichosis)

• A dystrophy or pigmentation

Certain classes of drugs have their own spectra of reactions, particularly:

• Hormones like antiandrogens.
• Chemotherapy drugs
• Anticoagulants
• Current and systemic corticosteroids
• Biological products
• Calcineurin inhibitors

• Epidermal growth factor inhibitors and targeted Cancer therapies

Who gets drug eruptions?

On average, about 2% of prescriptions for a new drug lead to a drug eruption.

• Allergic reactions For some drugs they are more common in women than men.
• exist genetic factors that predispose people to drug eruptions. These may include differences in the drug metabolism.
• Underlying viral infections and diseases can influence reactions.
• Previous allergic reaction to the drug or intolerance to the drug increases the risk of reaction to another drug. The more medications prescribed, the greater the likelihood of allergy.
• Cross reactions related to previous sensitivity to different medications, sunscreens, cosmetics, food, or insect bites can occur.

It should be noted that some symptoms are falsely attributed to a medication due to another cause.

What causes drug eruptions?

There are several causes of drug eruptions:

• True allergy: this is due to a immune mechanism
  • Immediate reactions occur within one hour of drug exposure and are IgE-mediated antibodies (urticaria, anaphylaxis).
  • Delayed reactions occur between 6 hours and several weeks from the first exposure to the drug. May be IgG mediated antibody, immune complex or cytotoxic T cells.
• Predictable reactions explainable by pharmacology.
• Medication intolerance (i.e., dose-related reactions)
• Pseudoallergy (i.e. a urticarial The reaction is supposed to be an allergy, but is actually due to the direct release of mast cells drug mediators [opioids [opioidsNSAID])

What are the clinical features of drug eruptions?

Additional systemic symptoms that accompany the drug eruption may include:

• Fever
• Discomfort
• Another organ compromise (in SCAR).

Complications of drug eruptions.

Incorrect attribution of the drug eruption can deprive the patient of a useful medicine or cause reappearance when the drug is taken at a later date.

SCAR patients can die from it. SJS / TEN can cause permanent scarring leading to blindness and deformity.

How are drug eruptions diagnosed?

A careful history, skin, and general physical examination are necessary to diagnose a drug rash and assess its severity.

• Determine any previous exposures to suspected medications.
• Review the medical history to determine the relationship between the onset of symptoms and the onset of medications.
• Some medications (such as antibiotics and antiepileptics) are more likely than others (such as heart medications) to cause drug eruptions.
• Medications may need to be stopped and then reintroduced to see if symptoms return. This is not certain if the patient had SJS / TEN or anaphylaxis.

Blood tests generally include blood count, liver function, and kidney function.

Eosinophilia it may or may not be present, and is nonspecific unless it has recently appeared.

Sometimes it is difficult to determine which medication is responsible for a rash, if any. Very few drug reactions have a confirmatory test.

• Skin intradermal/ The allergy specialist / immunologist can perform puncture tests to check for immediate reactions to penicillin and some other medications.
• Patch Sometimes the tests are done with medications believed to have caused rashes, but they can be difficult to interpret.

What is the treatment for drug eruptions?

The main thing is to identify and stop the responsible medicine as soon as possible.

The use of systemic steroids for drug eruptions, for example prednisone, is controversial. They are unnecessary if the rash is mild. Get advice from a specialist immunologist or dermatologist If the rash is severe.

• Topical corticosteroids (such as betamethasone cream) are safe in the short term and can reduce symptoms.

• Emollients It can be applied liberally and frequently.

• Drug-induced urticaria often responds to antihistamines, but they are rarely helpful for other eruptions.

Educate the patient to avoid re-exposure to responsible medication and the known drugs with which they cross-react.

How can drug eruptions be prevented?

Since the most serious drug eruptions are due to antibiotics, their use should be limited, and the underlying conditions should be treated in other ways whenever possible. For example, acne can be treated with isotretinoin.

Doctors should ask their patients about past medications. allergies when prescribing a new medicine. Drug allergies must be recorded in the medical record. Patients should remain alert and remind their doctor and pharmacist of any previous reaction they have experienced.

What is the prognosis for patients with drug eruptions?

Some patients can tolerate re-exposure to a drug that was thought to cause an earlier drug rash. Reasons for this may include:

• The medication was not responsible for the original symptoms.
• Drug sensitivity has been lost over time.
• The reaction may have depended on an underlying disease that has resolved itself.

For those with a confirmed drug allergy, an unrelated drug should be prescribed if necessary and when possible. Often these are more expensive, can be less effective, and can also have side effects and risks. Cross-reactions to similar drugs can occur due to a similar chemical structure or a drug class effect.

Graduate challenges and desensitization are sometimes carried out in specialized clinics.

Patients who have had severe Adverse drug reactions You must carry a wallet card and / or register with a drug allergy service.