Severe palmoplantar keratoderma

Abstract
Summary
Palmoplantar keratoderma (PPK), characterised by excessive epidermal thickening of the skin on the palms and/or plantar surfaces of the feet, can be hereditary or acquired. Here, we report a case of a 53-year-old woman with a history of sub-optimally controlled diabetes mellitus presenting with fevers and decreased Glasgow Coma Scale (GCS) to a tertiary hospital. She was diagnosed with diabetic ketoacidosis (DKA), with blood glucose at 40 mmol/L and ketones at 7 mmol/L, in the setting of a methicillin-sensitive Staphylococcus aureus necrotising soft tissue back infection. Her medical history included diabetes managed with insulin but no engagement with an endocrinologist or allied health support. Examination revealed an infected, necrotic back wound on her left mid-upper back that required surgical debridement and broad-spectrum IV antibiotics. In addition, she exhibited marked plantar keratoderma and onychogryphosis, reportedly present and worsening over approximately two years. She was prescribed 40% urea cream twice daily, resulting in gradual sloughing of the hyperkeratotic skin within a few weeks. Her HbA1c was 10.4%, and she tested negative for diabetes antibodies, indicating type 2 diabetes. Treatment included an insulin–dextrose infusion until DKA resolved, followed by twice daily insulin degludec/aspart (Ryzodeg 70/30) and metformin. The PPK was attributed likely secondary to sub-optimally managed diabetes.
Palmoplantar keratoderma (PPK) is a heterogeneous group of disorders presenting with excessive thickening of the skin on the palms and/or plantar surfaces of feet (1). It may be hereditary (autosomal dominant or recessive) or acquired, associated with systemic conditions such as uncontrolled diabetes, infections, inflammatory skin conditions or specific medications. Inherited forms can exhibit diffuse, focal or punctate patterns, sometimes as part of syndromes involving multisystemic features. The prevalence of PPK is estimated to be up to 4.4 per 100,000 people (2). Genetic mutations associated with PPK often involve keratins, desmosomes, desmogleins, loricrin, gap junctions and other structural proteins.

A 53-year-old Caucasian woman presented to a large tertiary hospital with a blood glucose level (BGL) of 40 mmol/L, ketones at 7 mmol/L, fevers and a decreased level of consciousness. She also had an infected wound on the left side of her mid-upper back and severe hyperkeratotic skin on the soles of her feet. She had a history of diabetes, although the type was unclear at the time of presentation, for which she had previously been treated with insulin. Her background included intellectual impairment, with no other significant medical or family history.

She was admitted for the management of diabetic ketoacidosis and septic shock, likely secondary to the infected back wound. She required ICU admission for intubation to protect her airway, along with an insulin–dextrose infusion, inotropic support and broad-spectrum antibiotics to manage her septic shock.

During her hospital stay, she was assessed by the dermatology team for marked hyperkeratosis on the plantar surfaces of both feet, which she reported had been present for at least two years and was gradually worsening. She was diagnosed with acquired PPK, likely due to sub-optimally controlled diabetes.

On examination, it was noted that pronounced, thick hyperkeratosis and keratoderma with a diffuse pattern covered the entire plantar surfaces of both feet. The hyperkeratosis was so extensive that it nearly encased the lateral and medial aspects of her feet in a pseudo-transgrediens manner (Fig. 1). Concurrent onychogryphosis was noted. Minimal PPK was evident on her hands. She showed no other features suggestive of a syndrome, such as ectodermal abnormalities in hair shafts or teeth, nor any history of cardiomyopathy or malignancies.

Figure 1 Right foot initial presentation.

She underwent surgical debridement of the back wound, which revealed a methicillin-sensitive Staphylococcus aureus necrotising soft tissue infection. This was treated with flucloxacillin.

Her HbA1c was 10.4%, and both anti-insulin and anti-glutamic acid decarboxylase antibodies were negative, indicating a likely diagnosis of type 2 diabetes. She was weaned off the insulin–dextrose infusion once she was extubated and able to tolerate an oral diet. She was then transitioned to twice daily Ryzodeg, with 12 units in the morning and 10 units in the evening, along with metformin 1,000 mg twice daily.

For her PPK, she was prescribed 40% urea cream, applied twice daily. Acitretin was considered as a systemic option to help reduce the hyperkeratosis; however, due to her critical condition and recent intubation, the risks were deemed to outweigh the benefits, so this systemic retinoid was not prescribed.

The urea cream helped soften the thickened skin, which gradually sloughed off over a few weeks (Figs 2, 3, 4, 5, 6, 7, 8, 9, 10). She was also seen by a podiatrist, who trimmed her toenails. This improved her mobility and enabled her to use a four-wheel walker. She was scheduled for discharge with a plan for early follow-up at the rapid-access diabetes clinic with the multidisciplinary team, followed by the ongoing care at the hospital’s diabetes clinic.

Figure 2 Right foot 2 weeks after using urea.Figure 3 Left foot 2 weeks after using urea.Figure 4 Left foot 2 weeks after using ureaFigure 5 Bottom right foot 1 month after using urea.Figure 6 Right foot 1 month after using urea.Figure 7 Left foot 1 month after using urea.Figure 8 Right foot 2 months after using urea.Figure 9 Top right foot 2 months after using urea.Figure 10 Left foot 2 months after using urea.