The first steps in history are as follows:

• Review the patient’s complete medication list.
• Document any history of previous adverse reactions to drugs or foods.
• Consider alternative etiologies (like: viral exanthems and bacterial infections).
• Note any concurrent infections, metabolic disorders, or immunocompromise.

In addition, the following should be noted and detailed:

• The interval between the introduction of a drug and the onset of the eruption.
• Route, dose, duration, and frequency of drug administration.
• Use of parenterally administered drugs (more likely to cause anaphylaxis).
• Use of topically applied drugs (more likely to induce delayed-type hypersensitivity).
• Use of multiple courses of therapy and prolonged administration (risk of allergic sensitization).
• Any improvement after drug withdrawal and any reaction with readministration.

Physical examination should address clinical features that may indicate a severe, potentially life-threatening drug reaction, including the following: Mucous membrane erosions, Blisters, Nikolsky sign, Confluent erythema, Angioedema and tongue swelling, Palpable purpura, Skin necrosis, Lymphadenopathy, High fever, dyspnea, or  hypotension

Drugs taken orally, injected, delivered by patch application, rubbed onto the skin (e.g. creams, ointments and lotions) can all cause reactions. The appearance of drug eruptions varies depending on the mechanism of the drug reaction.

Fibrosing reactions have been associated with a variety of chemical exposures. Nephrogenic systemic fibrosis has been associated with gadolinium contrast agents that used for MRI studies. Individuals with renal failure may have a buildup gadolinium in the skin and other organs and may recruit CD34-positive bone marrow-derived fibrocytes into lesional areas. Toxic oil ingestion has been associated with morphea, and Texier disease has been associated with phytomenadione (vitamin-K1) injections.

Name some drugs that occur reactions are: Amoxicillin, Trimethoprim-sulfamethoxazole, Ampicillin, Semisynthetic penicillin, Blood (human), Penicillin G, Cephalosporins, Quinidine, Gentamicin sulfate, Packed red blood cells, Mercurial diuretics, Heparin.

Drugs that commonly cause serious reactions are Allopurinol, Anticonvulsants, NSAIDs, Sulfa drugs, Bumetanide, Captopril, Furosemide, Penicillamine, Piroxicam, Thiazide diuretics,

Drugs unlikely to cause skin reactions are: Digoxin, Meperidine, Acetaminophen, Diphenhydramine hydrochloride, Aspirin, Aminophylline, Prochlorperazine, Ferrous Sulfate, Prednisone, Codeine, Tetracycline, Morphine, Regular insulin, Warfarin, Folic acid, Methyldopa, Chlorpromazine, Serotonin-specific reuptake inhibitors, Topical gels (like 4% tetracaine gel).

If a drug reaction is suspected, the suspected drug or drugs should be discontinued.

Treatment options depend on the nature and severity of the reaction. In an uncomplicated case, once the offending drug is withdrawn the condition is expected to improve.

Depending on the severity of skin lesions, may using emollients under wet dressings, topical or oral steroids, oral antihistamines, other medications or immunosuppressants, or hospitalization.

When a symptom arises, must consult with a doctor. Even, a delay will make costly.

• Clinical Dermatology
• Roxburgh’s common skin diseases