Discussion
This case report presents a rare familial cluster of EN secondary to
streptococcal infection, involving a mother and her two children. EN is
the most common form of panniculitis, characterized by tender,
erythematous nodules predominantly located on the anterior aspects of
the lower extremities (9, 10).Although the exact pathogenesis of EN
remains unclear, it is considered a delayed hypersensitivity reaction to
various antigenic stimuli, including infections, drugs, systemic
illnesses, and malignancies (3, 11).
The clinical presentation of EN in this familial cluster is consistent
with the typical features described in the literature, including the
acute onset of painful, erythematous nodules on the lower extremities
(6, 12). The presence of associated systemic symptoms, such as fever and
arthralgia, is also commonly reported in EN (13). The diagnosis of EN is
primarily based on the characteristic clinical findings, although a deep
incisional or excisional biopsy may be performed to confirm the
diagnosis and exclude other nodular lesions (3, 6).
Compared to the previous case report of EN, this familial cluster
presents a unique perspective on the potential genetic predisposition
and shared environmental factors contributing to the development of the
condition (14, 15). Familial EN is a rare subset of the disease, and its
exact prevalence remains unknown (16).The occurrence of EN in multiple
family members within a short time frame, as seen in this case, strongly
suggests a common triggering factor, such as streptococcal infection
(2).
The temporal relationship between the onset of respiratory symptoms and
the subsequent development of EN in all three family members supports
the role of streptococcal infection as the underlying cause.
Streptococcal pharyngitis is the most common identifiable cause of EN
(9, 17),and the elevated antistreptolysin O (ASO) titers in the patients
further support this etiology (2, 18).
The familial occurrence of EN in this case highlights the importance of
considering a family history in the diagnostic evaluation and management
of the condition (19). Genetic factors may play a role in the
susceptibility to EN, as suggested by the presence of human leukocyte
antigen (HLA) alleles in some familial cases [6,16]. However, the
specific genetic markers associated with familial EN remain to be
elucidated (9, 15).
In addition to genetic predisposition, shared environmental exposures
may contribute to the development of EN in family members (20). The
proximity of family members and the potential for transmission of
infectious agents, such as streptococcal bacteria, may explain the
clustering of EN cases within families (2, 20).
The management of EN primarily focuses on identifying and treating the
underlying cause, if present (9, 12). Supportive measures, such as rest,
leg elevation, and the use of nonsteroidal anti-inflammatory drugs
(NSAIDs) or potassium iodide, can help alleviate symptoms (9, 21). In
severe or refractory cases, systemic corticosteroids may be considered
(21). Furthermore, patients should be monitored for potential
complications or associated systemic diseases, particularly in the
setting of chronic or recurrent EN (22, 23).