Linear Lesions: Can You Diagnose the Skin Disease?

NEWS/ QUIZ

2 MIN QUIZ

Linear lesions on the leg of a 13-year-old female patient

A 13-year-old female presents with multiple linear, thickened, and hypopigmented lesions on the lateral side of her left leg, extending from above the knee to just below the ankle. The lesions range from 2 cm to 30 cm in diameter, appear indurated, and feel hardened to the touch. She reports that the lesions first appeared 18 months ago on the distal left calf as small, red patches of skin with some inflammation. Since then, the lesions have changed color and spread in a band-like pattern to their current presentation of patchy white lesions with thickened skin in the center and hyperpigmentation on the edges. The patient says the lesions are not painful, but the underlying muscle and subcutaneous tissue feel hard and taut around the areas affected by the lesions. She has no other systemic complaints. The patient is still growing, and there is no disparity in the length of her limbs. She has a family history of lupus erythematosus, and her mother was diagnosed with the autoimmune disorder 10 years ago as an adult. The patient has mild facial acne but no other cutaneous symptoms or signs of inflammation.

What is the diagnosis?

Select the correct answer

A) Linear atrophoderma of Moulin (LAM)

B) Linear lichen sclerosus

C) Linear morphea (scleroderma)

D) Linear lupus erythematosus panniculitis

E) Systemic scleroderma

CORRECT

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INCORRECT

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Answer is: C, linear morphea (aka localized scleroderma)

Morphea, also known as localized scleroderma, is a rare autoimmune disorder with an estimated incidence of 0.4 to 2.7 per 100,000 people.¹ Epidemiologic reviews of morphea reveal that the disease is more predominant in females than males (2.4 to 4.2:1), and patients identified as “white” make up 72.7% to 82% of the total patients treated for the disease.² Morphea affects both adults and children, with 50% of patients experiencing onset of disease during childhood and almost 90% of child patients presenting symptoms between 2 and 14 years old. In contrast, the mean age of adult onset is the mid-40s.^2,3 The 4 most widely recognized morphea subtypes are linear, generalized, plaque (or circumscribed), and mixed.¹ The most common subtype present in the pediatric population is linear, making up 42% of all morphea cases in children.^2,4 Additionally, the disease is much more common in patients with a family history of rheumatic and/or autoimmune diseases. For instance, a retrospective study of 245 patients with morphea found that 16% of children with linear morphea and 22% of children across all morphea subtypes had a first or second degree relative with an autoimmune condition.⁴

All clinical phenotypes of morphea are characterized by inflammation and sclerosis of the skin, subcutaneous tissues, and muscles that can lead to fibrosis and, in some cases, affect the underlying bone and the central nervous system.^1,2 Linear morphea can present as several different variants. The head variant (eg, En coup de sabre) involves linear induration on the dermis of the face, scalp, and underlying muscle, bone, and nerves. More commonly, linear morphea presents with lesions of the trunk and limb variant, with linear induration of the dermis, subcutaneous tissue, and sometimes underlying muscle and bone.^2,5 According to a recent study, patients with linear morphea were also 64% more likely to have a deeper involvement of symptoms and increased risk of disease activity and damage at the subcutaneous level than the other subtypes. Additionally, the lesions associated with linear morphea were more commonly found on the trunk and extremities (74.6%) than those associated with the head variant (37.5%).⁵

Morphea can cause cosmetic scarring of tissue, hair loss, sclerosis, and atrophy of the epidermis, dermis, and subcutaneous tissue if left untreated. There can even be functional impairment of the limbs and joints, interfering with bone growth.^1,5,6 Studies of pediatric patients with morphea have shown the disease can moderately impact patient quality of life, frequently causing pain and pruritus.¹

As the patient case above demonstrates, linear morphea lesions usually present with an initial phase of inflammation and erythema that harden the skin and range in color from red to purple, followed by a non-active phase in which lesions turn yellowish-white, thicken, and atrophy over time. These processes can sometimes cause darker areas of hyperpigmentation and hair loss due to an abundance of collagen.^1,2,6 Because the patient presented with scleroderma symptoms, linear morphea was suspected after an initial examination due to the location and shape of the lesions. Still, the guidelines recommend ruling out systemic sclerosis before making a linear morphea diagnosis. The early age of disease onset and the lack of nail fold capillary changes, swelling of hands, sclerodactyly of fingers, and presence of Raynaud’s phenomenon are key indicators to rule out systemic sclerosis.^2,6 Moreover, morphea is histologically challenging to diagnose because it is so similar to systemic sclerosis.²

For all patients with suspected morphea, a thorough physical examination and in-depth history should be conducted. Any signs and symptoms involving subcutaneous tissues and the musculoskeletal system warrant further examination by a rheumatologist and/or orthopedic specialist.¹ Delay in diagnosing morphea is usually due to physicians’ lack of expertise with the disease and its similarity to systemic sclerosis.¹ Recent research into understanding the longitudinal impacts of morphea has revealed that existing dermatology-based quality-of-life assessments do not fully capture the functional limitations caused by the frequent deep soft tissue involvement of linear morphea.⁵ Joint deformities (8% vs 0.4%) and a limited range of motion (26% vs 20%) are also more likely to occur in patients with linear morphea than those with generalized morphea.³ Localized scleroderma and lesions tend to resolve slowly, if at all, and the disease waxes and wanes. Some pediatric patients with localized morphea have an increased risk of developing systemic morphea in the future.^6,7 Therefore, it is recommended to treat the active disease and inflammation and monitor the cosmetic and functional sequelae to help prevent new lesions and improve long-term patient outcomes.^1,5

References:

1. Florez-Pollack S, Kunzler E, Jacobe HT. Morphea: current concepts. Clin Dermatol. 2018;36(4):475-486. doi:10.1016/j.clindermatol.2018.04.005

2. Fett N, Werth VP. Update on morphea: part I. Epidemiology, clinical presentation, and pathogenesis. J Am Acad Dermatol. 2011;64(2):217-230. doi:10.1016/j.jaad.2010.05.045

3. Prasad S, Zhu JL, Schollaert-Fitch K, Torok KS, Jacobe HT. An evaluation of the performance of current morphea subtype classifications. JAMA Dermatol. 2021;157(4):1-8. doi:10.1001/jamadermatol.2020.5809

4. Leitenberger JJ, Cayce RL, Haley RW, Adams-Huet B, Bergstresser PR, Jacobe HT. Distinct autoimmune syndromes in morphea: a review of 245 adult and pediatric cases. Arch Dermatol. 2009;145(5):545-550. doi:10.1001/archdermatol.2009.79

5. Kunzler E, Florez-Pollack S, Teske N, O’Brien J, Prasad S, Jacobe H. Linear morphea: clinical characteristics, disease course, and treatment of the morphea in adults and children cohort. J Am Acad Dermatol. 2019;80(6):1664-1670.e1. doi:10.1016/j.jaad.2019.01.050

6. Fett NM. Morphea (localized scleroderma). JAMA Dermatol. 2013;149(9):1124. doi:10.1001/jamadermatol.2013.5079

7. Giuggioli D, Colaci M, Cocchiara E, Spinella A, Lumetti F, Ferri C. From localized scleroderma to systemic sclerosis: coexistence or possible evolution [published correction appears in Dermatol Res Pract. 2018 Jun 5;2018:6984282]. Dermatol Res Pract. 2018;2018:1284687. doi:10.1155/2018/1284687

Image is licensed under the Attribution-Share-Alike 4.0 International

Source: L.z.motloung55, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

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