EAC is a rare cutaneous disease characterized by annular erythematous lesions. Generally, it can appear as a multiple polycyclic lesions simulating urticaria papules that enlarge centrifugally with central clearing. EAC was first described by Darier in 1916, and classified in 1978 by Ackerman into a superficial and a deep type [
2,
3]. The superficial type is characterized by perivascular lymphohistiocytic infiltrate of variable intensity in the papillary and middermis with occasional eosinophils. Edema of the papillary dermis is usually present. The epidermal changes of parakeratosis and spongiosis may be present. Clinically, these lesions have nonindurated borders, are scaly and pruritic. Instead, the deep type is characterized by perivascular lymphohistiocytic infiltrate of variable intensity in the superficial (papillary and middermis), but in addition the inflammatory infiltrate involves the deep dermis (reticular dermis). No epidermal changes are generally observed. Clinically, these lesions have indurated borders, are nonscaly and nonpruritic. The etiology and pathogenesis are unknown [
4]. It is believed that EAC represents a cutaneous manifestation of a type IV hypersensitivity reaction to different causes and underlying systemic diseases, including: food allergy, arthropod bites, drug reactions (finasteride, chloroquine, hydroxychloroquine, hydrochlorothiazide, piroxicam, etizolam, cimetidine, penicillin, salicylates, spironolactone, gold sodium thiomalate, amitriptyline, ustekinumab, rituximab), infections disease (bacterial, viral, parasitic, fungal, mycobacterial), endocrine and immunological disorders (menstrual cycle, Graves disease, Hashimoto thyroiditis, Sjögren syndrome, autoimmune progesterone dermatitis), hematological and other neoplastic disorders (Hodgkin lymphoma, non-Hodgkin lymphoma, acute leukemia, histiocytosis, multiple myeloma, nasopharyngeal carcinoma, prostatic adenocarcinoma, breast carcinoma, ovarian carcinoma) [
5‐
10]. Treatment and eradication of the underlying disease often resolves EAC. The prognosis for EAC is excellent, except when associated with an underlying malignancy and other systemic disease. It is important to highlight that EAC can appear many years before, concomitantly or after the onset of a malignancy. For all these reasons, a diagnosis of EAC should be followed by a full physical examination and diagnostic workup in order to exclude an underlying disorder. However, sometimes no causative agent can be identified and in these cases EAC is considered idiopathic. Our case represents the peculiar variant of AR EAC, which is only exceptionally reported in the literature [
1,
4,
11]. This variant has the same clinical and histopathological features of the classical superficial form of EAC and is usually observed in women (2:1). The average age of onset is 49 years; however, ages can range from 16 to 83 years [
11]. The lesions tend to involve the legs and arms and sporadically the trunk, while the face, hands and foot are always spared. The lesions, which appear constantly during the spring or summer months, tend to regress spontaneously after a variable period of days to months with yearly recurrence for many years. Normally, no causative agent can be detected and for this reason AR EAC is usually considered an idiopathic disease. Moreover, associated symptoms are generally not present. Nevertheless, a full physical examination and diagnostic workup is very important in order to exclude an underlying disorder. Until now no effective treatment has been described. Photosensitivity is a tempting theory but the presence of lesions in nonexposed skin areas and the absence of facial and trunk involvement seem to rule out the role of sun exposure. It could be hypothesized that environmental factors (temperature, seasonal plants or fungus) explain the periodic course of the disease, but further studies would be necessary.