Paronychia and Felon Are NOT Part of Hyper IgD Syndrome
Paronychia and felon are common bacterial infections of the finger that occur in immunocompromised patients but are not characteristic features or recognized manifestations of hyper IgD syndrome (mevalonate kinase deficiency). 1
Clinical Features of Hyper IgD Syndrome
The established manifestations of hyper IgD syndrome include:
- Recurrent febrile attacks starting in early childhood with elevated acute-phase reactants (CRP, SAA >30 mg/L) 2, 3
- Skin lesions during attacks consisting of erythematous macules (most common), erythematous papules, urticarial lesions, and erythematous nodules—occurring in 79% of patients 4
- Joint involvement with arthralgias or arthritis 3
- Abdominal symptoms including vomiting, pain, and diarrhea 3
- Cervical lymphadenopathy and occasionally splenomegaly 3, 4
- Headache during febrile episodes 3
The skin manifestations show histologic features of mild vasculitis, Sweet-like features, or nonspecific inflammation—not the purulent bacterial infections characteristic of paronychia or felon 4, 5.
Why This Distinction Matters
Paronychia and felon are superficial bacterial infections (most commonly Staphylococcus aureus) affecting the nail fold and fingertip pulp space respectively, requiring incision and drainage when advanced 6, 7. These infections:
- Occur in immunosuppressed patients as opportunistic infections 6
- Are not listed among the autoinflammatory manifestations in the comprehensive classification of primary immunodeficiencies 1
- Represent common hand infections in the general population, not specific to any particular immunodeficiency 6, 7
Clinical Pitfall to Avoid
Do not confuse the erythematous skin lesions that occur during hyper IgD syndrome attacks (which are inflammatory/vasculitic in nature) with bacterial soft tissue infections like paronychia or felon 4, 5. While patients with hyper IgD syndrome may theoretically develop bacterial infections during periods of immune dysregulation, paronychia and felon are not recognized diagnostic features or characteristic complications of this autoinflammatory disorder 1, 2.
If a patient with confirmed hyper IgD syndrome develops paronychia or felon, treat it as a separate bacterial infection requiring standard management (antibiotics and possible drainage), not as a manifestation of the underlying autoinflammatory condition 6, 7.