Manuscript:
Erythema annulare centrifugum (EAC) is a gyrate erythema, which is
classically characterized by annular, erythematous plaques with central
clearing and a trailing scale. Although its physiopathology remains
unclear, a hypersensitivity reaction to various external or internal
stimuli has been postulated. Recurrent forms of EAC are regarded as
peculiar clinical variants with intriguing precipitating factors
[1]. Recently, two cases of recurrent post tonsillitis EAC in adults
have been reported in literature. Herein, we present two rare cases of
children developing recurrent EAC following tonsillitis.
Case 1:
A 3-year-old boy presented to our Dermatology Department for a
two-month-history of recurrent asymptomatic skin lesions. There was no
history of potential trigger factors, such as drugs or tick bite.
Physical examination revealed multiple erythematous annular and
urticariform plaques, with a central clearing and non-scaling borders,
located on his face, his right limb and thighs (Fig1).
Oto-Rhino-Laryngological (ORL) examination revealed erythematous
tonsillitis. No mucosal lesions were present and the rest of the
physical examination disclosed no abnormalities. Hematologic (complete
blood count, sedimentation rate), biochemical (C-reactive protein) and
immunologic (anti-nuclear antibodies and anti-DNA antibodies)
investigations were within normal levels except for a high rate of
antistreptolysin O (ASLO). Careful questioning revealed that relapses
were always preceded by tonsillitis. Cutaneous lesions healed completely
after receiving adequate antibiotics and the child had no relapses after
one-year follow-up.
Case 2:
A 4-year-old girl presented with a four-month history of recurrent
self-healing erythematous plaques without fever or itch. These lesions
had annular disposition and polycyclic borders and were located on her
lower limbs (Fig2). Clinical examination revealed an erythematous
tonsillitis and no cardiac or osteoarticular involvement. The patient’s
mother stated that tonsillitis seemed to precede the skin lesions on
every recurrence. Blood investigations were non-contributory except for
a high rate of ASLO. Remission was obtained after treating the
tonsillitis and there were no relapses observed after a
4-month-follow-up.
EAC is considered to be a reactive process with a self-limited course
and good prognosis. Multiple inciting factors were reported in the
literature, mainly infectious such Epstein-Barr virus, dermatophytes,
Escherichia coli and recently streptococcal infection. Recurrent post
tonsilitis EAC is a controversial entity described by Elfatoiki et al in
two women, aged respectively 25 and 33 years, who presented with
relapsing annular erythema following streptococcal throat infection
[2]. The authors had performed a skin biopsy for their patients
revealing non-specific inflammation suggestive of a superficial form of
EAC [2]. For our two cases, we did not perform skin biopsy as the
clinical presentation was suggestive and the evolution was rapidly
regressive. The differential diagnoses of EAC include annular urticaria,
Sweet syndrome, lupus and other figurate erythema such as erythema
marginatum or erythema migrans [2]. Annular urticaria was not
retained in our two patients because the eruption was non itchy and a
prolonged centrifugal evolution was noted. Lyme disease, Sweet syndrome
and lupus were ruled out based on clinical and biological features.
Relapsing annular erythema following streptococcal throat infection with
a high rate of ASLO are highly suggestive of erythema marginatum, one of
the main Jones diagnostic criteria for rheumatic fever. Indeed,
according to Elfatoiki et al, the absence of: arthralgia, cardiac
involvement and biological inflammatory syndrome, suggests the diagnosis
of this recent entity [2].
Although streptococcal superantigens are widely known to play major
roles in reactive processes, the connection between throat streptococcal
infections and EAC is yet to be
established. Thus, we believe that accumulation of additional similar
cases is required to clarify the exact nature of this association.