Pustular psoriasis is a rare form of psoriasis characterized by an eruption of sterile pustules. It can be divided into both generalized and localized forms1. Some authors consider a separate variant of generalized psoriasis, well described by Lapière, as recurrent circinate erythematous psoriasis. It presents with erythematous, annular or polycyclic lesions, and an eruption of small sterile pustules and fine desquamation. The patches extend from the center and resolve within some weeks, leaving scales and changes in pigmentation and pigmentary changes. Frequent relapses are described in the bordering areas2,3.

In this study, we report the case of a woman affected by generalized annular pustular (Lapière) psoriasis. This patient had previously been treated with conventional therapeutics, and demonstrated a significant improvement after treatment with etanercept. This 70-year-old Caucasian woman, described in our report, has a 35-year history of psoriasis. Physical examination revealed the presence of small erythematous papules, centered by a pustule, a few millimeters in diameter (Fig. 1). Histological examination showed Kogoj-Lapière spongiform multilocular typical pustules (an epidermal pustule formed by infiltration of neutrophils into necrotic areas of the epidermis, where the cell walls form a swampy network), features compatible with the clinical diagnosis of Lapière psoriasis. The patient had previously been treated with other topical and systemic drugs (colchicine, acitretin, ciclosporin, methotrexate) and ultraviolet B narrow band phototherapy, with partial and temporary benefits, side effects, and frequent relapses. Differential diagnosis of our case included other generalized pustular psoriasis: acute generalized exanthematous pustolosis (AGEP) was perhaps the most important differential diagnosis. AGEP, which occurs as an acute, spontaneously healling reaction to drugs (usually antibiotics), was excluded on the basis of the absence of vasculitis associated with spongiform pustules and based on the presence of psoriatic anamnesis. Lapière psoriasis can be differentiated from pustular lesions caused by prolonged application of topical steroids or tar ointments on the periphery of pre-existent psoriatic plaques. Unlike the Von Zumbusch generalized form, the general state of health is not compromised.

The patient was treated with 50 mg of etanercept twice weekly subcutaneously for three months. There was an extremely rapid response, noticeable from the second day, with complete clearance of the pustular eruption at the end of the first week. At week 12 of etanercept treatment, complete clearance of cutaneous lesion was achieved (Fig. 2), including erythema and scaling, with no significant side effects reported, concomitant infections, decreased blood granulocytes or other laboratory changes. Maintenance treatment with 50 mg of etanercept once a week subcutaneously was continued for another three months. No relapse was noted at week 35.

There are no universally accepted guidelines for management of Lapière psoriasis; no clinical trials have been conducted and no single agent has been approved for this indication. Only case reports or short series of patients have been published on the off-label use of biologic drugs for pustular psoriasis4,5. In contrast, de novo paradoxical pustular flares induced by anti-tumor necrosis factor (anti-TNF-α) therapy have been described6.

Etanercept is a soluble recombinant human tumor necrosis factor α (TNF-α) receptor that acts as a competitive inhibitor of TNF-α by binding to and inactivating endogenous TNF-α, thereby preventing its interactions with cell surface receptors7. Based on our experience, etanercept may be an effective therapeutic option in the treatment of Lapière psoriasis. In fact, in our patient, etanercept demonstrated a high efficacy with a rapid and significant clinical response associated with an excellent safety profile. The rapid clearance, the good maintenance of efficacy and the excellent tolerability suggest a role for etanercept in the management of Lapière psoriasis, especially in elderly patients with typical pathologies. Specifically, this may apply if other treatment modalities are contraindicated or proven to be ineffective.