What is a common cause of vitiligo and erythema anulare centrifugum?

Common Cause of Vitiligo and Erythema Annulare Centrifugum

Autoimmunity is the most common underlying cause linking vitiligo and erythema annulare centrifugum, with thyroid autoimmune disease being a particularly important association to investigate. 1

Autoimmune Connection

• Vitiligo has strong evidence supporting an autoimmune etiology, with autoantibodies and T lymphocytes reacting against melanocyte antigens found in a significant proportion of patients 2
• Autoimmune thyroid disease is found in approximately 34% of adults with vitiligo, making it one of the most common associations 1
• The British Journal of Dermatology guidelines specifically recommend checking thyroid function in vitiligo patients due to this high prevalence of autoimmune thyroid disease 1
• Vitiligo is part of a broader genetically determined autoimmune and autoinflammatory diathesis that can manifest with multiple autoimmune conditions 3

Clinical Presentation and Diagnostic Considerations

• Vitiligo presents as depigmented patches that are often symmetrical and increase in size over time, corresponding with loss of functioning epidermal melanocytes 1
• Common sites for vitiligo include fingers, wrists, axillae, groins, and body orifices such as mouth, eyes, and genitalia 1
• Erythema annulare centrifugum (EAC) presents as erythematous papules that enlarge centrifugally to form figurate, annular or polycyclic plaques 4
• When both conditions are present, screening for underlying autoimmune disorders is essential, particularly thyroid disease 1

Diagnostic Approach

• For vitiligo diagnosis, Wood's light examination can help delineate areas of pigment loss, especially in patients with lighter skin types 1
• While vitiligo diagnosis is often straightforward in classical presentations, atypical presentations may require expert assessment by a dermatologist 1
• Blood tests for thyroid function and thyroid autoantibodies should be performed in all patients with vitiligo, especially when other autoimmune manifestations like EAC are present 1
• Skin biopsy may be necessary to confirm EAC, which typically shows a perivascular lymphohistiocytic infiltrate with eosinophils in the dermis 4

Management Implications

• Recognition of the autoimmune connection between these conditions guides treatment approaches 1, 5
• For vitiligo, topical treatments include potent topical steroids (limited to 2-month trials due to risk of skin atrophy) and calcineurin inhibitors like pimecrolimus or tacrolimus which have better safety profiles 1
• For widespread vitiligo, narrowband UVB phototherapy is recommended over PUVA due to greater efficacy 1
• Immunosuppressive therapies may be effective in treating both conditions when they occur together, further supporting the autoimmune etiology 2
• Monitoring for development of other autoimmune conditions is important in long-term follow-up 1, 5

Pitfalls to Avoid

• Failing to screen for thyroid disease in patients with vitiligo can miss an important treatable condition 1
• Treating isolated symptoms without addressing the underlying autoimmune process may lead to suboptimal outcomes 5
• Extended use of potent topical steroids beyond 2 months can cause skin atrophy 1
• Assuming all cases of vitiligo and EAC are autoimmune without considering other potential triggers such as infections or medications 4
• Overlooking the psychological impact of these visible skin conditions, particularly vitiligo, which can significantly affect quality of life 1