Acrodermatitis continua of Hallopeau is due to

Acrodermatitis continua of Hallopeau (ACH) is a rare inflammatory disease characterised by pustular eruptionsbeginning in the tips of fingers and toes (digits). The pustules may vary in extent over a chronic, recurrent course Acrodermatitis continua of Hallopeau is often triggered by localised trauma or infection at the distal phalanx(the tip of the digit). 80% begin in only one digit, most commonly the thumb. During acute flare-ups, the skin of the distal phalanx becomes red and scaly and develops small pustules. The pustules often join together and on bursting, reveal a painful, red and glazed area where new pustules then develop. Pustulation of the nail bed and its growth site (matrix) can result in onychodystrophy (malformation) and anonychia (loss of nail). Slowly, the disease can rarely spread proximally to affect the hand, forearm and/or foot. There may be osteolysis (destruction of bone) resulting in a wasted and tapered tip of finger or toe. In adults, acrodermatitis continua of Hallopeau may evolve into generalised Reference: GHAI Essential pediatrics, 8th edition