Lichen Amyloidosis (LA) is a rare chronic type of cutaneous amyloidosis, a skin condition marked by the buildup of amyloid deposits in the dermis and clinically manifested as pruritic, itchy skin, often pigmented, hyperkeratotic papules on the trunk and extremities, particularly on the shins, and histologically characterised by the deposition of amyloid or amyloid-like proteins in the.
Primary localised cutaneous amyloidosis (PLCA) is a disease in which aberrant protein clumps termed amyloids form in the skin, particularly in the wave-like projections (dermal papillae) between the top two layers (the dermis and the epidermis).
Patches of skin with atypical texture or colour are the most common symptom of PLCA. There are three types of amyloidosis based on the appearance of these patches: lichen amyloidosis, macular amyloidosis, and nodular amyloidosis.
Lichen amyloidosis is characterised by itchy, thicker skin areas with many tiny bumps. The patches have a scaly texture and are a reddish brown hue. The shins are the most common location for these patches, although they can also appear on the forearms, other areas of the legs, and other regions of the body.
Macular amyloidosis causes flat, dark brown spots on the retina. Although the coloration is generally consistent, it can have a lacy (reticulated) or rippling look. Patches of macular amyloidosis are most often observed on the upper back, but they can also appear on the torso or extremities. These patches irritate a little.
Firm, raised lumps (nodules) that are pink, red, or brown define nodular amyloidosis. These nodules are usually not itchy and appear on the face, torso, limbs, or genitals. The patches in some of the people who are affected resemble both lichen and macular amyloidosis. Biphasic amyloidosis is the name for this kind of amyloidosis.
The abnormal skin patches that appear in all types of PLCA generally appear in mid-adulthood. They can last anywhere from months to years and may reappear after they go, either in the same place or elsewhere. Systemic amyloidosis is a life-threatening disease in which amyloid deposits develop in tissues and organs throughout the body.
Amyloidosis is a disease in which the body’s tissues and organs collect an abnormal protein called amyloid. It has an impact on their form and functionality when this happens. Amyloidosis is a dangerous health condition that can result in organ failure and death.
What Causes the Disease?
Chronic friction, hereditary factors, and viral infection are all probable causes of lichen amyloidosis. The degraded keratin peptides of apoptotic keratinocytes converted by macrophages and fibroblasts are considered to be the source of lichen amyloidosis cutaneous amyloid deposits.
Who is at Risk of Contracting this Illness?
Although lichen amyloidosis is mostly sporadic, around 10% of cases are familial and have an autosomal dominant inheritance. People of Chinese descent tend to be more likely to acquire the illness.
Lichen amyloidosis is more frequent in women than in males, according to a research based on patients from Southeast Asia. It generally appears between the third and fifth decades of life.
Lichen Amyloidosis (LA)
Papular amyloidosis (PA), formerly known as lichen amyloidosis (LA), is the most prevalent kind of primary cutaneous amyloidosis, with amyloid deposits accumulating in the dermis. The hyperkeratotic and coalescent papules are frequently seen on the anterior tibiae and are very pruritic. A 70-year-old man presented with a pruritic papular eruption on his lower legs that had been present for two years (Figure 1).
Figure 1: A patient with Lichen Amyloidosis (LA) on the lower leg with a clinical picture.
Example of a Clinical Synopses
Figure 2A: A dermoscopic examination reveals a scar-like region with no structure.
An 80-year-old lady with high blood pressure and diabetes sought treatment for pruriginous lesions on the anterior surfaces of her legs and knees that had been developing for two years. On palpation of the lower limbs, the clinical examination revealed numerous yellowish papules that were hard and scratchy.
A skin biopsy revealed compact orthohyperkeratosis, acanthosis, and amorphous amyloid deposits in the dermal papillae, confirming the diagnosis of LA (Figure 2A). A pale scar-like core with structureless morphology surrounding by few brownish spots was seen under the microscope, which is highly unique to LA.
Clinical Synopses Picture
Figure 1: Patient #1’s conchal bowl has brown scaly 1-2 mm monomorphous papules.
Figure 2: Patient #2’s upper back has a rippled hyperpigmented rectangular plaque.
Figure 3: Patient #2’s right ear has monomorphous glossy brown 1-2mm papules in the conchal bowl and on the scapha.
Figure 4: Scanning magnification of the auricular papule in Figure 1. Acanthosis and hyperkeratosis can be seen in the papillary dermis, as well as a wide band of light-staining amorphous material. There isn’t a lot of inflammation. 40X magnification of hematoxylin and eosin stain.
Figure 5: Scanning magnification of an auricular papule depicted in Figure 3. Follicular plugging is a common occurrence. There is also acanthosis and a pauci-inflammatory infiltration. 40X magnification of hematoxylin and eosin stain.
Figure 6: is a magnified version of Figure 4. The globular appearance of the light amorphous material in the papillary dermis suggests amyloid. Hematoxylin and eosin stain at 200-x magnification.
Figure 7: An auricular papule from patient #1 as seen via an electron microscope. A jumble of randomly interwoven fibrils can be detected, which is typical of amyloid.
Figure 8: Shows the histopathology of the rippling plaque in Figure 2. A dermal papillae with an increased number of mononuclear cells is filled with subtle pink globules. 400X magnification of hematoxylin and eosin stain.
Figure 2B: Dermoscopy reveals a scar-like structureless region.
In the dermis, there are sarcoid granulomas.
The most common form of primary localised cutaneous amyloidosis is lichen amyloidosis . It’s diagnosed by pruritic keratotic patches on the front tibiae, as well as the trunk and upper extremities on rare occasions [1-2]. Mucinosis, lichen simplex chronicus, and prurigo nodularis are used as differential diagnoses [1-3].
The diagnosis is based on clinical evidence (Figure 2B). A skin biopsy should only be performed on lesions that are progressing. Chuang et al.  defined two primary dermoscopic patterns associated with LA: the ‘central hub’ and the ‘scar-like’ patterns.
There were two forms of ‘scar-like’ pattern identified, one resembling a volcano crater and the other with entirely structureless morphology, as we discovered in our case [1-4].
Even though clinical diagnosis of LA is the most common, dermoscopy may now confirm it.
Points to Remember
- Lichen amyloidosis usually starts as itchy pimples on the legs and spreads to the back, torso, and arms.
- Treatment is determined on the size and location of the lesions, and a dermatologist may be required.
- Lichen amyloidosis recurs often.
Treatment Options (Solutions).
Options for medical treatment
- Corticosteroids used topically.
- Calcineurin inhibitors used topically.
- Corticosteroids injected intralesionally.
- Dimethyl sulfoxide topical.
- Retinoids in the bloodstream.
- Cyclophosphamide is a drug that is used to treat cancer.
- The antibiotic cyclosporine.
Modes of physical activity
- UVB phototherapy (broadband and narrowband).
- Phototherapy using PUVA.
- Dermabrasion is the first step.
- Laser treatment using CO2
- Pulsed dye laser treatment is a third option.