Amyloidosishttps://en.wikipedia.org/wiki/Amyloidosis
Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue. Intensely pruritic hyperkeratotic papules that may coalesce to form gray to brown patches. The common site of involvement of the disease is the anterior tibiae and upper back.

○ Diagnosis and Treatment
#Electrophoresis of blood or urine
#Skin biopsy
  • Classic facial features of Amyloidosis
  • In the magnified view, hard papules with a similar shape are observed. They are relatively uniform and hard, unlike allergic disorders such as atopic dermatitis.
  • Skin features of amyloidosis cutis dyschromica ― (A) Hyperpigmented and hypopigmented macules on the lower leg
  • Lichen amyloidosis is often misdiagnosed as atopic dermatitis. A typical case presents with small hard papules and itching.
  • The lesion of Amyloidosis may resemble that of atopic dermatitis.
References Lichen amyloidosis - Case reports 24130236 
NIH
A 26-year-old woman presented to our clinic with an itchy rash on her legs that had persisted for 10 years. The rash had previously been treated with topical steroids and tazarotene cream, with no improvement. The patient’s family history was noncontributory. A physical examination showed discrete and coalescing hyperkeratotic tan-brown papules on the pretibial surfaces, consistent with lichen amyloidosis.
 Lichen Amyloidosis: Towards Pathogenesis-Driven Targeted Treatment 36763750 
NIH
Lichen Amyloidosis (LA) is an uncommon, primary cutaneous amyloidosis associated with chronic, idiopathic pruritus. Clinical presentation of LA includes skin colored to hyperpigmented, papules coalescing into plaques with a rippled appearance on the extensors.1 LA most commonly presents in the fifth to sixth decade of life and has no curative treatments. Overall response to current therapies is poor.
 Clinical Characteristics of Lichen Amyloidosis Associated with Atopic Dermatitis: A Single Center, Retrospective Study 38086357 
NIH
Lichen amyloidosis (LA) is a chronic pruritic skin disorder characterized by multiple grouped hyperkeratotic papules, predominantly located on the back, shins, thighs, and arms. Histological analysis of LA shows amyloid deposition in the papillary dermis and hyperkeratosis and acanthosis of the epidermis. The exact pathogenesis of LA has not yet been elucidated; however, prior reports have implicated frictional epidermal damage, apoptosis, viral infection, and many other triggers. LA is reportedly associated with several skin disorders, including atopic dermatitis (AD), lichen planus, and mycosis fungoides.