A 52-year-old woman presented to a primary care clinic with a 3-week history of rash on her feet that had spread to her hands in the previous week. She described the rash as painful, burning, and itching with no drainage. She denied any recent illness, fever, chills, medication changes, or environmental exposures. Home treatments included Epsom salt baths and lotion with no improvement.
Past medical history included hypertension. She was a smoker with a 30-pack-year history and drank alcohol on a daily basis. Her medications included losartan and atorvastatin.
On examination, multiple papular and scabbed lesions were present with mild scaling. Additional review of systems and physical exam were benign. A KOH prep showed hyphae. The patient was diagnosed with tinea pedis and prescribed fluconazole (150-mg tablet once per week for 2 weeks).
Two weeks later, after completing the antifungal therapy, the patient returned with pain limiting her ability to bear weight or grasp objects. Clinical examination showed well-demarcated erythematous scaly and hyperkeratotic plaques with scattered papular and pustular lesions on bilateral palmar and medial aspects of plantar surfaces (see Figures 1 and 2). A repeat KOH was not completed. The patient was diagnosed with palmoplantar pustulosis (PPP).
PPP is a chronic, relapsing, inflammatory skin condition that results in painful lesions on the palms and the soles.1,2 There is debate as to whether PPP is a variant of psoriasis or a separate condition; depending on physical manifestations, one can be diagnosed with palmoplantar plaque psoriasis, PPP, or a combination of the two.3,4
The exact cause of PPP is unknown; however, increased levels of inflammatory cytokines interleukin (IL)-17 and IL-22 may be involved in the pathogenesis of the disease.5 Additional genetic and environmental factors, most significantly smoking, play an important role in its development.2,6
Inflammation associated with PPP typically manifests in the classic features of pustules that coalesce and resolve over several days, resulting in brown macules, hyperkeratosis, fissures, and debilitating pain.4,7 Some patients may have co-occurring onycholysis resulting from nail dystrophy and destruction or plaque psoriasis elsewhere on their body.8 PPP often persists for years with periods of exacerbation and remission, and it significantly affects the patient’s ability to perform activities of daily living without pain.8,9 It is exceedingly rare and most commonly affects middle-aged women with a smoking history or current smoking status.7
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