Palmoplantar inflammation with a broad differential diagnosis made clear upon patch testing

ABSTRACT

A 51-year-old woman presented to our service with a 2-year history of severely painful, thickened skin of her bilateral hands and feet. She advised of considerable skin pain on mobilizing. She intermittently applied acrylate nails. This was on a background of chronic urticaria, asthma and allergic rhinitis. She described a positive family history of psoriasis. On examination, there was marked hyperkeratosis with welldemarcated erythema on the central palms and entire fingers with deep fissuring and scale. Similar finding were noted on the soles of the feet particularly affecting the heels, arch and also the tips of the toes. The morphology of the lesions favoured psoriasis, but the differential diagnosis included chronic hand dermatitis. She was referred for topical psoralen + ultraviolet A (PUVA) and patch testing to standard battery and acrylates. Treatment with topical PUVA was discontinued and patch testing lists were cancelled as a result of the emergence of COVID-19 in Ireland. Topical therapy of clobetasol propionate was initiated. On follow-up review, the appearances of her feet and hands had deteriorated significantly. She was commenced on acitretin 10 mg once daily, which was escalated to 20 mg 2 months later. Clinical improvement was noted, but appearances deteriorated once again following the application of acrylic nails. Further history revealed the patient had assisted with the application of acrylic nails to clients years prior to her initial review. Patch testing took place 18 months after initial review due to outpatient list cancellations secondary to the COVID-19 pandemic. Upon review 48 h after the application of the (METH) Acrylate Series, the patient was found to have a +2 reaction to 2- hydroxyethyl methacrylate and a further +2 reaction to 2- Hydroxypropyl methacrylate. At her 96-h review, both reaction sites were marked at +1. Following complete avoidance of acrylates, the palmoplantar inflammation entirely resolved. This case highlights the importance of a detailed clinical history where contact dermatitis is considered. In our patient's case, the clinical history and examination of the palmoplantar eruption combined with the first-degree family history of psoriasis were highly suggestive of a diagnosis of psoriasis. The episodic severe flares and its refractory nature to treatment raised suspicion for allergic contact dermatitis. Dermatologists should remain alert for potential contact allergens in cases of severe palmoplantar psoriasis. A further area for consideration is the deleterious effect the COVID-19 pandemic had on the successful diagnosis and treatment of dermatological patients through the cancellation of outpatient services.