There are dense “spots” and papules on the legs, which are itchy and unbearable. also recurs. Is it keratosis pilaris? Or eczema?
In fact, it may be neither, but a condition called cutaneous amyloidosis. In view of the fact that many friends have repeatedly proposed to understand this disease, today I will tell you about cutaneous amyloidosis.
What is amyloidosis?
Amyloidosis is the deposition of amyloid protein in tissues or organs. And lead to the deposition of tissues or organs with varying degrees of dysfunctional diseases.
Amyloid is a general term for a class of biochemically unrelated proteins. Named for its amyloid chemical reaction (eg, iodine-positive staining). But actually it has nothing to do with the starch we are familiar with in carbohydrates.
When amyloid deposits only in the skin, it is called cutaneous amyloidosis. Its predilection sites are the limbs, mainly the extensor side of the calf. Occurrence in the face is relatively rare, and it is more likely to be misdiagnosed and missed. The disease is more common in Southeast Asia, China, the Middle East and South America.
Main categories of cutaneous amyloidosis
Cutaneous amyloidosis is a common chronic skin disease. Its etiology, pathogenesis, and tissue origin remain unclear. May be related to long-term friction, genetics, viruses, environmental factors, etc.
Cutaneous amyloidosis can be divided into primary, secondary, primary systemic, and secondary systemic types. Among them, primary cutaneous amyloidosis is more common.
Primary cutaneous amyloidosis is characterized by skin lesions and intradermal amyloid deposits. According to different clinical manifestations, it can be divided into lichenoid amyloidosis (more common), plaque-like amyloidosis, nodular or enlarged (tumor) amyloidosis, etc.
When lichenoid and plaque-like amyloidosis occur in the same patient, it is called biphasic amyloidosis.
In addition, less common types include cutaneous heterochromic amyloidosis, frictional cutaneous amyloidosis, bullous cutaneous amyloidosis, and anal and sacral cutaneous amyloidosis, among others.
Lichenoid amyloidosis, also known as lichenoid amyloidosis, is the papular form of primary cutaneous amyloidosis. It is more common in middle-aged people, and it occurs on both sides of the calf. It may also be present on the outside of the arms, waist, back, and thighs.
Accompanied by severe itching, the skin lesions were brown to brown-black maculopapular rash, hard, flat and polygonal. Hyperpigmentation or hypopigmentation often occurs at the rash. No self-healing tendency, generally does not affect health.
More common in middle-aged and elderly women, mainly in the back interscapular region. It can also occur on the extremities, chest and buttocks. The rash is a cluster of brown or purplish-brown patches 1-3 mm in size. Mild to moderate pruritus is generally present, and approximately one-fifth of patients have no pruritus.
Nodular cutaneous amyloidosis
Also known as amyloidoma, it is more common in middle-aged women. It can occur on the face, trunk, extremities, and genitals. The rash is smooth and red or tan. Some patients are also accompanied by diabetes, Sjögren’s syndrome and so on.
Also known as nylon brush plaque-like amyloidosis. The reason is that the patient rubs or scratches with nylon towels, brushes, etc. for a long time. Causes skin damage, flaking and inflammation. Finally, moss-like changes are formed. Friction can also cause hyperpigmentation.
Occurs in areas prone to friction, such as the scapula, interscapularis, and extremities. The rash is a dark brown patch or plaque with a corrugated surface, mild scaling, and often visible scratches and blood scabs. The disease course is usually slow. 5-10 years.
How to treat and improve amyloidosis
Although skin amyloidosis is harmless to the body, it affects the appearance and itching is unbearable. If necessary, it is recommended to see a dermatologist for treatment. You can usually take a hot shower to keep skin lesions clean. Avoid excessive scratching or rubbing irritation. Do a good job of moisturizing.
Cutaneous amyloidosis is a relatively refractory skin disease, and there is currently no specific treatment, mainly symptomatic treatment to relieve and improve symptoms.
Retinoids commonly used to treat cutaneous amyloidosis include acitretin, acitretin, and isotretinoin. Relevant studies have reported that oral acitretin has a certain effect on some patients with cutaneous amyloidosis.
For macular or papular cutaneous amyloidosis (lichen amyloidosis), oral antihistamines (such as loratadine) can be used to relieve itching. Potent topical corticosteroid preparations (eg, halometasone cream), calcipotriol, or phototherapy. Local intradermal injection of glucocorticoids can also be used. or topical retinoic acid.
Nodular cutaneous amyloidosis can be surgically removed. Or choose curettage, cautery, cryotherapy, dermabrasion, CO2 laser or pulsed dye laser therapy. But easy to relapse.