Apremilast is a potentially useful treatment for severe palmoplantar pustulosis with extra-palmoplantar symptoms

Abstract

Palmoplantar pustulosis (PPP) is a chronic inflammatory skin disorder affecting the palms and soles. In rare cases, severe patients develop acute extra-palmoplantar lesions often accompanied by arthralgia. Such cases with extensive symptoms often necessitate systemic treatments with variable efficacy and potential side effects. Apremilast, known for its broad immune response modulation, presents promise as a therapeutic option for severe PPP with joint and extra-palmoplantar lesions. This case highlights apremilast as a potential systemic treatment for such cases with minimal side effects.

FIGURE 1

Clinical manifestations (a–e) before and (f–j) 1 year after treatment with apremilast. (a,b) Large, painful pustules repeatedly developed in the palms and soles. (c) Nail deformities in the proximal areas of the nails. Note the oedematous erythema in the posterior nail fold. (d,e) Extensive skin lesions in extra‐palmoplantar regions. Poorly demarcated erythema with papules and pustules on the trunk. (f,g) Skin lesions on the palms and soles showed marked improvement with apremilast. (h) The erythema in the posterior nail fold and the disruptive nail deformity are resolved. Small pittings reside in some of the nails. (i,j) Improvement of skin lesions in the trunk and limbs with light pigmentation.

FIGURE 2

(a) Close‐up image of extra‐palmoplantar skin lesions. Poorly demarcated erythema with papules and pustules on the trunk (yellow arrow). (b) Histopathology of the skin specimen taken from the extra‐palmoplantar skin lesion in the trunk showed mild acanthosis and subcorneal accumulation of neutrophils (haematoxylin–eosin staining, scale bar = 250 μm). (c) Close‐up image of a lesion on the heels, close to the sole. Skin specimen was taken from the pustule circled in black dots. (d) The specimen showed subcorneal accumulation of neutrophils (haematoxylin–eosin staining, scale bar = 100 μm).

FIGURE 3

A diagram showing the mode of action of apremilast in Palmoplantar pustulosis (PPP), based on the proposed mechanism of action in various cell types observed in vitro studies. Apremilast modulates a broad spectrum of inflammation via PDE4 inhibition in diverse immune cells and tissue‐specific cells in the skin and joints. IL, interleukin; LTB4, leukotriene B4; TNF, tumour necrosis factor.