Fixed drug eruption (FDE) is an allergic skin reaction or mucocutaneous area due to the use of certain drugs. Characterized by the emergence of repeated lesions in the same location. Drugs are generally harmless if used according to the dosage and indications. A drug allergy occurs when there is an abnormal response of the immune system to a substance.
General symptoms of drug allergy :
- Red patches on the skin.
- Itchy.
- Swollen.
- Dizzy.
- Out of breath.
- Anaphylaxis.
Disease equation :
- Fixtum exanthema.
- Fixed exanthem.
Etiopathogenesis.
Drugs that often cause Fixed drug eruption (FDE) :
- Oral contraceptives.
- Barbiturates.
- Phenolphthalein.
- Phenacetin.
- Salicylates.
- Naproxen.
- Nystatin.
- Minocycline.
- Sulfonamides.
- Tetracycline.
- Metronidazole.
- Curtain.
- Sulindac.
- Tolmetin.
- Malate.
- Bleomycin.
- Busulfan.
- Zidovudine.
- Chlorpromazine.
- Hydantoin.
- Cyclophosphamide.
- Clofacimine.
- Antimalarial.
- Procarbacin.
- Doxorubicin.
Skin reactions to drugs can occur through immunologic or non-immunological mechanisms. Drug eruption is a drug allergy that occurs through an immunologic mechanism. This occurs in patients who are hypersensitive to certain drugs.
Light molecule drugs act as incomplete antigens (haptens). Drugs in the form of haptens must first combine with proteins, tissues, serum from cell membranes to form antigen complexes (hapten protein complexes).
Drugs with heavy molecules can function directly as complete antigens.
Factors that determine a drug in eliciting an immune response :
- Molecular characteristics and sensitization.
- Individual metabolic variation.
- Immunogenetic ability.
- Age.
Factors influencing the occurrence of Fixed drug eruption (FDE) :
- Drug exposure.
- Incident time.
- Drug use elimination test.
- Repeated drug use.
Clinical description.
Fixed drug eruption (FDE) is characterized by :
- One or several erythematous lesions.
- Lesions often appear on the face and genital area.
- Causes injuries such as burns.
- Although acute inflammation resolves slowly, local hyperpigmentation persists with repeated drug exposure.
- The lesion will reappear in the same place.
- New lesions are round or oval in shape.
- Plaque-shaped with an erythematous appearance.
- The skin will turn purple or brown.
- Lesions usually develop within 30 minutes - 8 hours after drug administration.
- The lesions are initially solitary but with repeated administration of the drug new lesions may reappear and existing old lesions may enlarge.
- Lesions are more common on the limbs of the hands, feet, genitalia (glans penis) and perianal area.
- Lesions may appear around the mouth and eyes.
Characteristics of Fixed drug eruption (FDE) :
- Reactions occur after repeated use of the drug. Reaction time 8-9 days.
- The manifestation of a drug eruption does not depend on the pharmacological and chemical use of the drug.
- Very small amounts of the drug can induce a severe reaction, even if the drug has been used for a long time.
- The same drug can cause different reactions in the same person at different times.
Supporting investigation.
The diagnosis of fixed drug eruption (FDE) can be made by histopathological examination.
Diagnosis.
The diagnosis of Fixed drug eruption (FDE) is based on :
- History.
- Clinical abnormalities.
- Special inspection.
Treatment.
Causal treatment ️ Avoiding allergy-causing drugs (if the drug has been determined). Avoid drugs that have a chemical structure similar to allergy-causing drugs (one class).
Systemic treatment➡️ Corticosteroids, and Antihistamines.
Topical treatment➡️ Topical treatment depends on the condition of the skin disorder, dry or wet. If the skin is wet it can be compressed. If the skin is dry, you can use a corticosteroid cream.
Identification of the drug causing Fixed drug eruption (FDE) ️➡️ knowing the chronology of the administration of these drugs. Only drugs that have been used for 8-21 days are included in the suspect list.
Prognosis.
Fixed drug eruption (FDE) will heal if the cause can be identified and immediately removed.
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