Clinical Features:

• Clinically similar to lichen planus, but often larger, and with a predilection for the trunk and extremities
• Sometimes photodistributed
• May occur months to years ofter the patient is started on the offending drug, in contrast to the typically shorter latencies seen with other types of drug reactions
• Occasionally, lesions may become eczematous, psoriasiform, bullous or ulcerative.
• Complications include postinflammatory hyperpigmentation, scarring alopecia and anhidrosis.
• Among the most commonly involved drugs are:
  • Gold salts
  • Penicillamine
  • β-blockers
  • Lithium
  • Furosemide
  • Spironolactone
  • Antimalarials
  • Captopril
  • Ethambutol
• Lichenoid drug eruptions may also be caused by cutaneous contact with such agents as p-phenylenediamine, nickel, gold and dental restorative agents.

Histologic Features:

• The findings are very similar to those of lichen planus, and lichenoid drug eruption is often histologically indistinguishable from that entity.
• Features that may help distinguish lichenoid drug eruption in some case are:
  • Focal parakeratosis
  • Spongiosis
  • A frequently thinner epidermis
  • Less pronounced hypergranulosis
  • Eosinophils and occasional plasma cells
  • Cytoid bodies in the upper stratum granulosum or even the stratum corneum
  • Focal interruption of the granular layer
  • Exocytosis of lymphocytes into the upper epidermis
  • Deep dermal perivascular infiltrate

Cases associated with this book:

Lichenoid drug eruption
Author: Artur Zembowicz M.D. Ph.D.

Conference: DermatopathologyConsultations.com Teaching Collection