Skin-nontumor / Clinical dermatology
Granulomatous but non-infectious disorders
Interstitial granulomatous drug reaction (dermatitis)

Author: Mowafak Hamodat MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 2 June 2016, last major update June 2011

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Interstitial granulomatous drug reaction (dermatitis)

Definition / General
  • Reaction due to beta blockers, calcium channel blockers, lipid lowering agents, ACE inhibitors, diuretics, NSAIDs, antihistamines, antidepressants and oral hypoglycemic agents; often more than one of the above
  • Mean duration of 5 years before onset of eruptions
  • Resolves a mean 8 weeks (range 1 - 40) after drug is stopped
  • May be due to exaggerated immune response to drugs
Clinical Features
  • Violaceous to erythematous, nonpruritic plaques with bizarre shapes, or annular morphology on skin folds (axilla, inner arms, groin, medial thighs and popliteal fossa)
Case Reports
Micro Description
  • Diffuse granulomatous dermatitis with interstitial histiocytes and giant cells near collagen and elastic fibers, often with piecemeal fragmentation of collagen, giant cell engulfment of elastic fibers and variable interstitial mucin (J Cutan Pathol 1998;25:72)
  • Usually interface dermatitis with basilar vacuolopathy and focal dyskeratosis with lymphocytes at dermoepidermal junction
  • Usually tissue eosinophilia, lymphoid atypia with hyperchromatic nuclei, convoluted nuclear contours (including a few cerebriform nuclei in dermis), variable involvement of hair follicles and acrosyringia
  • Rare collagen necrobiosis
  • Usually no fibrin deposition within vessels or vasculitis
Micro Images

Images hosted on other servers:

Figure 1: ankle plaques; 2 - 4: diffuse interstitial and perivascular histiocytic infiltrate in dermis and subcutis, with occasional lymphocytes and eosinophils; epidermis has basilar vacuolopathy and dermoepidermal lymphocytes



Various images

Differential Diagnosis