Acrodermatitis Continua Suppurativa of Hallopeau
Last Updated: 2025-05-15
Author(s): Navarini A.A.
ICD11: -
Last Updated: 2025-05-15
Author(s): Navarini A.A.
ICD11: -
Acrodermatitis continua suppurativa of Hallopeau is a rare, chronic skin disease with sterile pustule formation on the tips of the fingers and toes (acres). Painful pustules on atrophic skin on the nail bed and nail matrix are typical. Repeated episodes lead to nail dystrophy and even nail loss (anonychia). It is seen as a localized variant of pustular psoriasis, with an aggressive course on the distal extremities.
The disease is extremely rare, exact data is lacking. Mostly affects middle-aged adults; Caucasian patients often aged 40-50, Asian cohorts tend to have it earlier (30s). Slight preponderance in women. Pediatric cases are rare, partly associated with genetic predispositions (e.g. IL36RN mutations). Epidemiology is primarily based on case series.
ACH is assigned to the localized pustular forms in the psoriasis spectrum. It exclusively affects the acra (distal fingers/toes) and associated nails. In contrast to the generalized form, infestation is usually limited to individual fingers/toes. It is considered an independent entity, but is therapeutically and pathogenetically related to pustular psoriasis and is sometimes seen as a continuum to palmoplantar pustulosis.
The exact cause is unclear. It can be triggered by minor trauma or local infections (Koebner phenomenon). It is an auto-inflammatory skin process. Genetic factors play a role: mutations in the IL36RN gene (IL-36 receptor antagonist) are frequently found, especially at an early onset, leading to uncontrolled IL-36 inflammation with pustules. Mutations in CARD14 and AP1S3 have also been found. Immunologically, excessive innate reactions dominate: Keratinocytes and neutrophils interact, proinflammatory cytokines (IL-1/IL-36 family) are central. It is a sterile neutrophilic dermatosis in the context of psoriasis.
Usually starts on one finger (often thumb/index finger) with redness, pustules on the tip. Pustules are sterile, painful, confluent and can detach the nail. After bursting, erosions remain on which new pustules form. Chronically affected fingers show atrophic skin, scaling, new pustules. Ongoing inflammation leads to severe nail dystrophy, nail loss (anonychia) due to involvement of the nail fold/matrix. Disease spreads over months/years to other fingers/toes, but usually remains limited to a few; often asymmetrical. Rarely spreads to the back of the hand/feet. Affected fingers/toes are painful under pressure, sometimes swollen (dactylitis), functionally limited. Psoriatic joint complaints of the distal interphalangeal joints may occur. Systemic symptoms are absent.
The diagnosis is clinical. Leading symptom: chronic persistent pustulation on finger/toe end phalanges with nail destruction and lack of pathogen detection. Clinical indication: localized, sterile pustules on the nail bed that do not heal despite antimicrobial treatment. Exclusion of infections is important: pustule culture is sterile, fungal diagnosis (onychomycosis, Candida) necessary. Histopathology supports diagnosis: neutrophilic pustules in epidermis, no germs. No specific laboratory tests. Imaging (X-ray) may show late bony changes. No standardized diagnostic criteria. Nail involvement is central; if this is absent, consider other diagnoses (palmoplantar pustulosis). Genetic test (IL36RN) can help in unclear cases/children, but the majority are negative for the mutation.
The disease characteristically affects the distal acres: Fingertips (more common) and toe tips. Often begins on just one finger, usually the thumb. In the course of the disease, other, sometimes symmetrical fingers may be affected. However, remains limited to fingers/toes, does not affect large areas of skin outside the hands/feet (differentiation from GPP). The central feature is the constant involvement of the nail apparatus (bed, matrix, wall); pustules are periungual and subungual. Frequently several fingers of one hand are affected, often asymmetrically. Rare infestation of all fingers. Extension to the palm of the hand/sole of the foot or other regions practically never occurs in isolated ACH.
Symptoms often begin after minor injury (manicure, splinters, burns) or infection (nail bed inflammation). Initially redness/swelling, then sterile pustules. Often misdiagnosed as an infection, antibiotics/surgery unsuccessful. Pustules persist, nail becomes brittle, becomes detached. Underneath, weeping, painful wound with new sterile pustules. Chronic recurrent course. Numerous unsuccessful attempts at therapy. Family history rare (except monogenic mutation). In children, often very early onset (infancy/toddlerhood), initially suspected infection. Long duration, considerable burden on quality of life.
Characteristic: Intraepidermal, spongiform pustules according to Kogoj (neutrophil accumulations), often subcorneal, also in sweat gland ducts. Psoriasiform widening of the epidermis, fresh lesions thin/atrophic. Dermis: Moderate perivascular lymphohistiocytic infiltrate. Old lesions: Fibrosis. Nail matrix: Neutrophilic/lymphocytic infiltrates, acanthosis. Important: No bacteria/fungi (skin germs secondary). Differentiation from differential diagnoses: No acantholysis (such as Darier's/pemphigus), neutrophilic microabscesses such as pustular psoriasis.
No specific prevention known. Not primarily caused exogenously. Avoid injuries/irritations on the acra (possible relapse trigger: Koebner). Avoid aggressive nail manipulation in the case of psoriasis/pustular reactions. Early dermatological clarification for persistent acne pustules -> rapid therapy can prevent spread/worsening. Avoid incorrect treatment: Stop repeated antibiotics/surgery for suspected infection if ACH is suspected. Main strategy: minimize triggers, if suspected, early adequate therapy to reduce secondary damage.
Treatment difficult, individualized, often multimodal. No guidelines, based on case reports. Topical: Highly potent glucocorticoids, vitamin D₃ analogs. Rarely topical retinoids (tazarotene), tacrolimus. Keratolytics for keratinization. Systemic conventional: retinoids, immunosuppressants. Acitretin often first-line for pustular psoriasis. Ciclosporin in severe cases, acts quickly. Both improve, but long-term tolerability limited. Methotrexate less successful. Dapsone rarely tried. Phototherapy (PUVA) adjuvant locally, limited effect on pustulosis.Â
Biologics Breakthrough in resistant cases. TNF-α inhibitors (etanercept, adalimumab, infliximab) rapid/sustained improvement. Adalimumab successful in children, can achieve remission. IL-17 inhibitors (secukinumab, ixekizumab) higher response rates, improve refractory (secukinumab almost complete healing in studies). Ustekinumab (IL-12/23-p40) effective, especially in PsA. Newer IL-23p19 inhibitors (tildrakizumab, guselkumab) rare, evidence limited (tildrakizumab complete remission reported). IL-1 inhibition (anakinra off-label) reduced pustules with IL36RN mutation. IL-36 receptor blockers: spesolimab (anti-IL-36R) approved for acute GPP relapses, successful in severe ACH (almost complete healing after infusion) -> targeted blockade of central inflammatory pathway, promising for refractory/IL36RN. Children also often receive biologics (adalimumab).
