Acrodermatitis continua of Hallopeau (ACH) is a disorder well known to dermatologists, but absolutely mysterious to everyone else. It is now considered a localized form of pustular psoriasis of the digits that may be accompanied by onychodystrophy and osteolysis.
In my experience, patients come to me having been unsuccessfully treated with antibiotics or antifungal agents. They have proven to be somewhat recalcitrant to topical antipsoriatic therapies (steroids, calcineurin inhibitors, vitamin D analogues, or retinoids) and are seeking other options. Phototherapy may be utilized. All of the standard systemic agents have been reported occasionally effective in ACH (methotrexate, retinoids, cyclosporine, tetracycline, dapsone, and colchicine), and increasingly, the biologics, initially with the TNF inhibitors (infliximab, etanercept, and adalimumab) may be considered (1). Brachytherapy has been reported to be effective in ACH (2).
According to Qi et al, ACH is thought to be a variant of pustular psoriasis with deficiency of interleukin (IL)-36 receptor antagonist (DITRA) for several reasons: 1) their similar histopathological features; 2) the evidence that many cases of ACH progress to generalized pustular psoriasis (GPP) and; 3) both ACH and GPP can be caused by mutations in the IL36RN gene, which encodes interleukin-36 receptor antagonist (IL-36Ra) (3). Cordoro et al reported the case of an adolescent man with GPP who was found to have a homozygous mutation within the IL36RN gene; he was successfully treated with the anti-IL-17 agent, secukinumab. Elevated IL-36 levels in psoriatic lesions have been correlated with increased levels of IL-17, but the relationship between IL-36 and T helper 17 cell (Th17) differentiation remains largely unknown. This case suggests a pathomechanistic link between defective IL36RN and Th17 differentiation in the skin of patients with DITRA (4). It is therefore no surprise that the latest reports in treating ACH focus on IL-17.
Muggli et al detail the case of an 87-year old man with biopsy-proven ACH, where immunohistochemical stains demonstrated strong expression of IL-17. He responded well to secukinumab, with complete resolution of inflammation of the affected fingers after 6 weeks of therapy, accompanied by nails that began to grow normally (5).
When reading through the April 2017 issue of JAMA Dermatology I saw the following full-page ad: “Coming Soon. Guselkumab”. In the Passover spirit, I asked “Why is this biologic different from all other biologics?”
Guselkumab, is a fully human immunoglobulin G1 (IgG1) monoclonal antibody that specifically inhibits intracellular IL-23 and downstream signaling by targeting the p19 subunit. Guselkumab decreases blood and skin lesion levels of effector IL-17A and decreases epidermal hyperplasia and inflammation by downregulating T cells and myeloid dendritic cells. Guselkumab has demonstrated 75% and 100% of PASI 90 improvement at 16 and 24 weeks, respectively. It may also increase safety by maintaining the IL-12/Th1 axis, an important regulator of immune function, unlike the previous medications that targeted both IL-12 and IL-23 (6).
To date there are no reports of utilizing guselkumab for ACH. I’m not clairvoyant, but you don’t need to be a wizard to see that report coming to the literature in 2018.
- Sehgal VN, et al. Acrodermatitis continua of Hallopeau: Evolution of treatment options. Int J Dermatol 2011; 50: 1195-1211.
- Pinard J, et al. Novel application of high-dose-rate brachytherapy for severe, recalcitrant acrodermatitis continua of Hallopeau. JAMA Dermatol 330; 153: 331-2.
- Qi Y, et al. Acrodermatitis continua of Hallopeau with granuloma-like vegetation, osteolysis and IL36RN mutation. Acta Derm Venereol 2017; 97: 122-3.
- Cordoro KM. Response to interleukin ((IL)-17 inhibition in an adolescent with severe manifestations of IL-36 receptor antagonist deficiency (DITRA). JAMA Dermatol 2017; 153: 106-8.
- Muggli D, et al. Secukinumab for acrodermatitis continua of Hallopeau. JAMA Dermatol 2017; 153: 336-7.
- Nawas Z, et al. A review of guselkumab, an IL-23 inhibitor, for moderate-to-severe plaque psoriasis. Skin Therapy Lett 2017; 22: 8-10.
*I have no financial or other conflict of interest with Janssen Pharmaceuticals of Johnson & Johnson