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Update Summary

May 1, 2023

The following section was updated:

  • Added self-assessment questions and answers


For the Chapter in the Schwinghammer Handbook, please go to Chapter 16, Dermatologic Drug Reactions and Common Skin Conditions.



  • image Patients presenting with a skin condition should be interviewed thoroughly regarding signs and symptoms, urgency, other subjective complaints, and medication history. The skin eruption should be carefully assessed to help distinguish between a disease condition and a drug-induced skin reaction.

  • image Drug-induced skin reactions may be caused by systemic or topical medications and can be irritant (if topical route) or allergic (topical or systemic route) in nature.

  • image Allergic drug reactions can be classified into exanthematous, urticarial, blistering, and pustular eruptions. Exanthematous reactions include maculopapular rashes and drug hypersensitivity syndrome. Urticarial reactions include urticaria, angioedema, and serum sickness-like reactions. Blistering reactions include fixed drug eruptions, Stevens-Johnson syndrome, and toxic epidermal necrolysis (SJS/TEN). Pustular eruptions include acneiform drug reactions and acute generalized exanthematous pustulosis. Other drug-induced skin reactions include hyperpigmentation and photosensitivity. Genotyping may help identify patients at higher risk of a severe reaction.

  • image Not all skin reactions are drug induced. In clinical practice, a diagnosis of drug-induced skin reaction is often a diagnosis of exclusion (ie, the diagnosis is reached after other possible diagnoses have been ruled out).

  • image Contact dermatitis is a common skin disorder caused either by an irritant contactant or an allergic/sensitizing contactant, resulting in irritant contact dermatitis (ICD) or allergic contact dermatitis (ACD).

  • image An ICD is confined to the area of chemical contact, whereas an ACD may extend beyond the areas of contact. However, it may sometimes be difficult to differentiate an ICD from an ACD.

  • image Patch testing is a criterion standard for the diagnosis of ACD—the crucial investigative and diagnostic method used together with a detailed clinical history and physical examination/workup.

  • image The first goals of therapy in the management of contact dermatitis involve identification, withdrawal, and avoidance of the offending agent. A thorough history, including occupational history, must be carefully reviewed for potential contactants.

  • image Other goals of therapy for contact dermatitis include providing symptomatic relief, implementing preventive measures, and providing coping strategies and other information for patients and caregivers.

  • image Photoaging is premature skin aging most commonly due to sun exposure.

  • image Skin cancers include squamous cell carcinoma, basal cell carcinoma, and malignant melanoma.

  • image Skin manifestations of COVID-19 infection go beyond the chilblains-like lesions commonly called “COVID-toes,” and may also present as morbilliform/maculopapular, papulosquamous, vesicular, urticarial, or erythema multiform-like lesions. In addition, purpuric pressure ulcers or vascular lesions (petechiae, purpura, and livedo) may present in patients with COVID-19.



Two patient cases are given later in this chapter to enhance learning, as follows:

  1. Patient case 1 – Dermatologic drug reaction

  2. Patient case 2 – Contact dermatitis...

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