Interstitial granulomatous dermatitis in an infant with juvenile idiopathic arthritis

Authors:

Introduction

Interstitial granulomatous dermatitis (IGD) is an uncommon entity characterized histologically by an interstitial granulomatous infiltrate. IGD has a polymorphic clinical presentation and is associated with an underlying inflammatory disease. Autoimmune disease, lymphoproliferative disorders, and medications are the main triggers reported in literature (1). Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease of childhood. JIA is characterized by arthritis with unknown cause, beginning before the age of 16 years old and lasting more than 6 months (2). We describe a patient with JIA who developed an IGD. This combination has been reported rarely in the literature, never during the infancy.

Case report

A 15-month-old male infant, from a non-consanguineous marriage, was referred to our department for a two weeks history of asymptomatic erythematous plaques on the trunk and limbs. The infant had a JIA that had been diagnosed two months earlier. He was treated with oral non-steroidal anti-inflammatory drug. Physical examination revealed multiple irregularly shaped, annular erythematous plaques on the trunk (fig 1) and upper arms. Skin biopsy showed an inflammatory infiltrate of the dermis composed mainly of histiocytes with an interstitial and palisaded arrangement (fig 2). There were also areas of collagen degeneration. The epidermis was normal. Alcian blue staining revealed mucin deposition. These findings, together with the clinical presentation, were diagnostic of IGD. Clobetasol proprionate 0.05% ointment was prescribed for the patient to be applied once a day. Reassessment after two weeks found a substantial improvement.

Discussion

Both adult and pediatric IGD are uncommon conditions. Infantile IGD is extremely rare (1-3). Adult IGD primarily affects middle-aged women (1). Akinshemoyin et al reported a female predominance in pediatric population with mean age of 12.7 years at diagnosis and predilection to ethnic minorities. As in our case, lesions of pediatric IGD are mostly asymptomatic, edematous, annular and erythematous to violaceous plaques with a predilection for extensor extremities and trunk (3). Palpable cord-like lesions known as the rope sign are classic in adult IGD (1). In pediatric cases, the rope sign is often absent (3). IGD is characterized histologically by an interstitial infiltrate of histiocytes in the reticular dermis with areas of collagen degeneration (1). In children, it seems to be a strong association between IGD and systemic lupus erythematous. The onset of IGD could be concomitant or precede the diagnosis of SLE. In lupic children, IGD lesions imply a flare of poorly controlled disease and could indicate a therapeutic escalation (3). Melanie A et al reported an association between IGD and uveitis in a 6-year-old girl. IGD had thus been included in the list of granulomatous condition associated with uveitis (4). Furthermore, Magro and Crowson described IGD in a 6-year-old girl with rheumatoid arthritis (5).

Skin involvement is classically described among JIA extra articular manifestations. Among the seven subgroups of JIA, skin findings occur in psoriatic arthritis as well as systemic and polyarticular JIA (6). Tsai HY et al reported a skin rash in 67.9% of cases of systemic onset JIA (7). Rheumatoid nodules, guttate and plaque psoriasis are the other most reported skin manifestation of JIA (6). An association between JIA and Harlequin ichthyosis, although rare, remains plausible (8). Giani T et al noted morphea in about 1% of JIA cases (9).

To the best of our knowledge, the first and unique case of a child with IGD and IJA has been reported in 2013. It was about an 11-year-old girl who had concomitant polyarthritis and skin lesions in the lower extremities. Symptoms resolved after treatment by oral corticosteroids and hydroxychloroquine (10). Our patient represents the second case of an infantile IGD with IJA. The association could be explained by an alteration in the balance of the immune system secondary to different genetic and environmental factors. Physicians should be aware of this uncommon association in order to set up proper investigation and treatment in these cases.

Author contributions:

Drs Malek Ben Slimane and Takwa Bacha contributed to the first draft of the manuscript. Drs Malek Ben Slimane, Takwa Bacha, Nourredine Litaiem and Meriem Jones contributed to the literature search, analysis, and interpretation of the data. Dr Soumaya Rameh and Dr Faten Zeglaoui critically revised the manuscript and gave final approval. All authors read and approved the final manuscript and agree to be finally accountable for ensuring the integrity of and accuracy of the work.

Conflict of interest: none

Ethics statement: Consent for publication has been obtained

Funding sources: none

References

Figures

Figure 1-a: Multiple irregularly shaped, annular erythematous plaques on the trunk

Figure 1-b: Multiple irregularly shaped, annular erythematous plaques on the upper arms

Figure 2 : Skin biopsy showed an inflammatory infiltrate of the dermis composed mainly of histiocytes with an interstitial and palisaded arrangement (HE; X40)