Drug Reactions

Drug reactions can be classified to:

  • Morbilliform (Measles like) most common
  • Urticarial (hives) second most common
  • Fixed drug
  • Photo sensitivity
  • Hypersensitivity Vasculitis
  • Severe reactions including Stevens Johnsons Syndrome


  • Most common drug reaction
  • It is type IV hypersensitivity reaction
  • It starts 1-2 weeks after drug ingestion-sooner if reused in the future
  • It causes pink bumps and patches that coalesce to form large lesions
  • It spares the palms and soles
  • Taking Amoxil when having Infectious Mono can produce this type of reaction

Treatment: Stop the drug, antihistamine and steroids

Drug reactions


  • Second most common drug reaction
  • Type I hypersensitivity with IgE mediated release of histamines
  • It starts within minutes to hours after exposure
  • It causes Weals/hives with some skin swelling and itching
  • In severe cases it may cause Anaphylactic Reaction with throat swelling and drop in blood pressure and can be life threatening

Treatment:if severe—> Epinephrine injection (EpiPen)
                 If mild to moderate—>Antihistamines and steroids

Fixed Drug Eruption

  • The rash recur at the same skin site with each repeated exposure
  • It usually found on lips, face, fingers and genitals
  • It causes a pink to purple bump with central dusky discoloration that may turn to blister
  • Lesions resolve with muddy brown post inflammatory hyperpigmentation

Polymorphous Light Eruption

  • Most common idiopathic photosensitivity disorder
  • It occurs in spring and early summer
  • It persists for weeks and resolves without scarring even with continuous sun exposure

Photo toxicity

  • It occurs with ingestion of certain chemicals or drugs
  • It presents with exaggerated severe sun burn after minor exposure


  • Typically occurs after topical application of a sensitizing agent
  • It causes itchy eczema like eruption

Hypersensitivity Vasculitis

  • It is a small vessel Vasculitis
  • It causes palpable bleeding spots under the skin (Purpura or Petichiae)
  • It may be associated with fever, Joints pain and swollen lymph nodes

If you think  you have any of the symptoms above, Contact Medical Care One is an urgent care and Walk-in clinic in Ypsilanti

Visit Urgent Care Near You.  All Walkins are welcome and no Appointment  Necessary. Can’t make it to the urgent care?   Meet your doctor online with  Telemedicine.  Read about COVID-19 safety info. 

Call Now Button (734) 330-2800