In dermatology, DHR stands for Dermal Hypersensitivity Reaction. It's not a specific disease itself, but rather a histopathologic finding—meaning it's observed in a skin biopsy—that indicates an allergic or inflammatory response in the skin. Many different skin conditions can show DHR on a biopsy.
Understanding Dermal Hypersensitivity Reaction (DHR)
DHR is diagnosed by dermatopathologists (doctors who specialize in skin biopsies) by examining a skin sample under a microscope. It's characterized by certain microscopic features in the skin tissue which suggest an allergic or inflammatory reaction is occurring. The clinical presentation (what the skin looks like) varies greatly depending on the underlying cause. This means that while the microscopic findings are the same, the visible symptoms can be very different.
Examples of conditions that can show DHR:
- Chronic pruritus of unknown origin (CPUO)
- Drug reactions
- Arthropod bite reactions (insect bites)
- Spongiotic dermatitis (a type of eczema)
- Bullous pemphigoid (a blistering skin disease)
- Scabies (a mite infestation)
- Urticarial erythema multiforme (a type of rash)
- Various other forms of dermatitis
Common primary lesions associated with DHR often include: papules, papulovesicles, plaques, patches, or erythema (redness). However, the appearance can vary significantly.
Important Note: While dermatopathologists use DHR as a diagnostic descriptor in biopsy reports, it is not considered an accepted clinical disease entity in itself. It points towards an underlying condition requiring further investigation and diagnosis.
Dr. Maxwell A. Fung, from the Department of Dermatology at the University of Connecticut School of Medicine, has published research on the clinical and histopathologic spectrum of DHR. (Source: https://pubmed.ncbi.nlm.nih.gov/12451376/) His work highlights the variety of conditions that can present with DHR. Further research continues to explore the significance and implications of DHR in dermatology.
