DISCUSSION
Pyoderma gangrenosum being a rare disease was first elaborated in 1930
and described as a chronic destructive inflammatory, noninfectious skin
disease with recurrence tendency.1,2 PG lesions
typically present as painful, erythematous pustules, bullae, or
nodules.1,3-6 They may evolve into necrotic plaques
with raised edges or into violaceous deep ulcers with undermined bluish
borders, healing with atrophic or cribriform scars. Such description
matches with what was seen in our case report.1,2,4-8
PG affects mainly adults aged between 20 to 50 years with female
predilection. It account for only 4% of cases in children and
adolescents with a higher incidence of head and perineal involvement. PG
has preponderance of pustular lesions, and a frequent history of trauma.1-3,5,6,8-10 The commonest presentation of PG in
children is disseminated ulcerative lesions. 1,6,8
The actual pathogenesis of PG has remained to be idiopathic though it
has been postulated to be a neutrophilic disorder characterized by
dysregulation of the immune system, such as overexpression of growth
factors and interleukins, especially interleukin (IL)-1, (IL)-6 and
(IL)-8 and tumor necrosis factor (TNF)-a.10
Though the etiology has been idiopathic in majority of cases, in about
fifty-percent of cases, it’s associated with neoplasms and/or systemic
inflammatory illnesses, such as Behcet’ disease, ulcerative colitis and
Crohn’s disease.4,7 More recently, PG has been
associated with novel drug therapies like
pegfilgrastim.2
The diagnosis of pediatric PG is often delayed, with an average of 2
months due to its lower prevalence among children and because it can be
misdiagnosed with other ulcerative diseases. 1,2,6This correlate with what was seen in this case where the diagnosis was
delayed for 6-months.
Though there are no histopathological findings specific to PG, but skin
biopsy should be performed to rule out other
etiologies.1.3,4,6 In resource limited settings, its
diagnosis remains to be clinical.
Once the diagnosis of pediatric PG is confirmed, clinicians are
recommended to identify for an underlying etiology as the disease can be
the initial presentation of a systemic disorder.1 This
was a challenge to our case since the patient was residing at a
resource-limited setting.
The head and neck region may be affected by PG, although to date only
few cases of ear involvement have been reported.1,6,8This is the first novel case reported in our country involving the
external ear.
To date, there is no gold standard treatment or published algorithm for
choice of therapy for pediatric PG though treatment should be tailored
according to the underlying etiology. It includes systemic steroids,
corticosteroid sparing agents such as dapsone and cyclosporine, and
TNF-alpha inhibitors such as adalimumab and infliximab. Response to
treatment is high with cure rates reaching 90%.6,10
Our patient achieved a rapid response when treated with steroids with no
recurrence after 6-months of follow up thus laying emphasis on the role
of steroids in PG. Auricular cases previously reported showed good
response to the classical therapeutic strategy based on the use of
corticosteroids or neutrophil chemotaxis inhibitors and thus use of
these drugs as first choice. No cases of auricular PG treated with
anti-TNF-biologic agents have been reported from the available
literatures. Thus, its value in managing refractory cases of auricular
PG is unknown, as already shown in PG of other
sites.10 Despite the good response to steroids
manifested in auricular PG cases, yet clinicians must expect episodes of
flare-up in some patients, as usually observed in most cases of typical
pyoderma. No flare has been reported in this case report.