Nodular prurigo

Specialty: Skin.

• Hyde's nodes
• Hyde's nodular prurigo
• nodular lichen simplex chronicus

Why it occurs

• Repetitive vicious cycle of chronic and intense scratching initiated by an underlying pruritic dermatosis (atopic dermatitis, psoriasis)
• Chronic neuropsychiatric disorders such as severe anxiety, obsessive-compulsive disorder or depression
• Systemic diseases associated with chronic uremic or cholestatic pruritus (renal failure, primary biliary cirrhosis)
• Small fiber neuropathy that alters cutaneous sensory perception
• Immunosuppression or chronic infections such as HIV or hepatitis C.

Initial workup

Skin biopsy with a 4 mm punch of an active nodule to confirm massive hyperkeratosis, irregular acanthosis and a characteristic neural proliferation in the papillary dermis with nonspecific inflammatory infiltrate. General analysis that includes complete blood count, creatinine, transaminases, alkaline phosphatase, serum IgE and serologies for HIV and hepatitis.

Standard management

• Clobetasol propionate 0.05% cream or ointment applied under occlusion — to penetrate the keratotic barrier of the nodule; controlled use due to risk of atrophy
• Intralesional triamcinolone acetonide — dose of 10-20 mg/mL injected at the base of the nodule every 4 weeks to reduce itching and flatten the lesion
• Gabapentin — oral neuromodulator useful for itching of neuropathic origin and the control of compulsive scratching, starting dose of 300 mg/day, gradually escalating according to tolerance
• Dupilumab (monoclonal antibody directed against the IL-4/IL-13 receptor, indicated in severe refractory cases of nodular prurigo).