A clinical, histological, and immunohistochemical comparison of acrodermatitis chronica atrophicans and morphea
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Acrodermatitis chronica atrophicans (ACA) and morphea are distinct dermatoses, identifiable by clinical and histological differences. However, some morphea cases show histological overlap with ACA, complicating diagnosis.
Area of Science:
- Dermatology
- Infectious Diseases
- Rheumatology
Background:
- Acrodermatitis chronica atrophicans (ACA) is a skin condition caused by Borrelia burgdorferi infection.
- Morphea is a connective tissue disease with a debated etiology, potentially linked to Borrelia in some instances.
- Distinguishing ACA from morphea is crucial for accurate diagnosis and treatment.
Purpose of the Study:
- To define the clinical and histological differences between ACA and morphea.
- To assess the diagnostic challenges in differentiating these two dermatoses.
- To investigate the role of Borrelia infection in morphea.
Main Methods:
- Clinical comparison of 19 ACA patients and 40 morphea patients.
- Histological examination of skin biopsy specimens.
- Immunohistochemical analysis using lymphocyte markers, including HLA-DR.
Main Results:
- ACA typically affects acral sites in older individuals, presenting as livid, ill-defined discoloration.
- Morphea can occur at any age/site, showing peripheral extension and distinct histological features like sclerosis.
- Histological differentiation was impossible in 17% of morphea cases; morphea histology did not correlate with positive Borrelia serology.
Conclusions:
- ACA and morphea are generally distinguishable clinically and histologically.
- Histological overlap exists in a subset of morphea cases, posing diagnostic challenges.
- Borrelia etiology for morphea is not supported by histological findings in this study.
Abstract:
We compared 19 patients with acrodermatitis chronica atrophicans (ACA), a dermatosis caused by Borrelia burgdorferi infection, and 40 patients with morphea, a disease of heterogeneous origin where a borrelia etiology has been suggested in some cases, both clinically and histologically to define the differences between these two dermatoses. Clinically, ACA involves acral body sites with lower temperatures, is seen mostly in elderly persons, and presents as a livid discoloration that is not sharply demarcated. Morphea can be localized in embryonal structures, affects any age and body site, and exhibits extension at the periphery of the lesions. Histologically, ACA shows atrophy of collagen and elastic tissue as well as hypertrophic basophilic elastic tissue; whereas in morphea, sclerosis and polarizing elastic tissue are prominent. Graft-versus-host-like reactions may be present in both dermatoses. Immunohistochemical testing with different lymphocyte markers showed differences only in the expression of HLA-DR antigens. These conditions can be distinguished from each other on a clinical and histological basis in most cases. In 17% of morphea biopsy specimens, however, histological differentiation from ACA was not possible. Moreover, the histological pattern of morphea was not associated with a positive borrelia serology.