11: Benign flesh-colored, pink, and red skin growths

Abstract:

The vast majority of growths on the skin are benign. To appropriately reassure patients of their benignity and to manage them accordingly, it is important for clinicians to be familiar with the broad range of benign skin lesions. This chapter reviews many flesh-colored, pink, and red common benign skin lesions that are not discussed elsewhere.

Key terms:

lichen simplex chronicus

keloid

erythema nodosum

cherry angioma

digital mucous cyst

pearly penile papules

chondrodermatitis nodularis helicis

Chapter outline

Lichen Simplex Chronicus
Keloids
Erythema Nodosum
Digital Mucous Cyst (Digital Myxoid Pseudocyst)
Pearly Penile Papules
Cherry Angioma
Chondrodermatitis Nodularis Helicis

Lichen simplex chronicus

Clinical features

Lichen simplex chronicus (LSC; also known as “neurodermatitis”) is a common secondary skin condition characterized by the development of thickened plaques with accentuated skin lines (i.e., lichenification).

• LSC is caused by chronic scratching or rubbing.

• Patients do not always report frequent rubbing or scratching of the affected area.
• Plaques are typically well demarcated but can take on irregular, ovular, or angular morphologies and can vary in size.

• Concomitant excoriations are frequently present.

• Newly formed plaques are usually characterized by separate zones.

• The peripheral zone (2–3 cm) is defined by marginal skin thickening, often with discrete papules.

• The central zone has greater degrees of skin thickening and exaggerated skin lines.

• Secondary pigmentation changes may be more dramatic in individuals with darker skin.

• Plaques may be hyperpigmented or hypopigmented, depending on chronicity.
• LSC most commonly affects areas that are accessible to scratching, such as the scalp, legs, neck, genitals (Fig. 11.1), arms, and face.

LSC can either arise in areas affected by a different primary dermatosis (e.g., atopic dermatitis [AD]) or de novo from idiopathic pruritus.

• In some cases of de novo LSC, it is thought to arise as a manifestation of an underlying psychiatric condition (e.g., generalized anxiety disorder, obsessive compulsive disorder [OCD]).

Differential diagnosis

The differential for LSC includes squamous cell carcinoma (SCC), lichen sclerosus, prurigo nodularis, lichen planus (LP), and psoriasis. Importantly, lichenification can arise secondary to a number of pruritic skin conditions. In all cases, it is important to recognize that patients may have a separate, underlying primary skin condition (including those in the differential diagnosis).

• SCC can also present as an isolated hyperkeratotic plaque. SCC is always in the differential for LSC. Cases of suspected LSC that demonstrate no response to occluded, super-potent topical corticosteroids or intralesional corticosteroids should be biopsied to rule out SCC. Importantly, this biopsy should be interpreted by a dermatopathologist because reaction changes seen in LSC can mimic SCC.
• Genital LSC can be confused with lichen sclerosus. Unlike LSC, which presents with thickened skin, lichen sclerosus presents with atrophic white plaques that burn in a perigenital distribution. The appearance of lichen sclerosus has been likened to that of cigarette paper. Untreated lichen sclerosus can cause genital disfigurement and can lead to development of SCC.
• Prurigo nodules are similar to LSC; however, they are nodular and frequently more widespread. Both conditions are caused by chronic scratching, rubbing, or picking.
• Hypertrophic LP can present with hyperkeratotic plaques, typically affecting the shins. It can be differentiated from LSC because hypertrophic LP typically presents with multiple lesions and typical LP lesions may be identifiable elsewhere.
• Other chronic inflammatory conditions (e.g., AD, psoriasis) can mimic LSC and can develop secondary lichenification from chronic scratching. In these cases, a primary dermatosis is also identified.

Work-up

LSC can typically be diagnosed clinically; however, histopathologic confirmation is occasionally necessary.

The presence of an isolated, lichenified plaque with accentuated skin lines and dyspigmentation is suggestive of a diagnosis of LSC.

• This is further supported by a patient history of repetitive scratching to the affected regions; however, many patients deny scratching.
• Visualization of broken hairs or excoriations may support a diagnosis of LSC because they are signs of chronic scratching.
• The presence of a primary dermatosis does not in and of itself rule out a diagnosis of LSC.

Patients who do not respond as expected to a 4-week course of occluded, super-potent topical corticosteroids or intralesional corticosteroids should undergo biopsy to rule out more significant pathology.

Initial steps in management

General management comments

Management of LSC differs based on whether or not the patient has an underlying primary dermatosis.

• If a primary dermatosis is present, treatment should initially be directed at managing the underlying condition.
• If there is no primary dermatosis, LSC-directed management should ensue.

• Some providers screen for the presence of comorbid psychiatric illness in patients with LSC and refer appropriately based on the results of screening.

Recommended initial treatment

Patients should be treated with either potent topical corticosteroids under occlusion or intralesional corticosteroids.

• For nonfacial, nongenital lesions, class I corticosteroids (e.g., clobetasol propionate 0.05%) can be occluded under saran wrap daily for 2 to 4 weeks.
• For facial or genital lesions, a 2-week trial of a nonoccluded mid-potency corticosteroid (e.g., triamcinolone acetonide 0.1% cream) twice daily can be trialed.
• Intralesional corticosteroids (e.g., triamcinolone acetonide 10 mg/kg for nonfacial, nongenital skin; triamcinolone acetonide 5 mg/kg for facial or genital skin) can be performed and repeated at 4-week intervals as needed.
• Intralesional corticosteroids are highly effective for solitary lesions but should only be performed by an experienced healthcare provider because they can result in significant local AEs if injected inappropriately.
• Patients should also be advised to keep lesions covered with bandages and to apply a thick moisturizer (e.g., zinc oxide barrier cream) to the affected area every time that it itches. This is frequently helpful with breaking the itch-scratch cycle that drives this condition.

Partial but inadequate response

If there is a partial but inadequate response after a trial of topical or intralesional corticosteroids, confirm the diagnosis, if it is in question, with a biopsy. Then add systemic anti-itch medications (e.g., gabapentin, pregabalin, n-acetylcysteine) or consider referral to a dermatologist.

• A punch biopsy is frequently required to obtain a sample of the entirety of the epidermis.
• You can also assess for patient willingness to seek cognitive behavioral therapy/psychiatrist evaluation to help break the itch-scratch cycle if an underlying psychiatric condition is suspected or known.

Warning signs/common pitfalls

SCC can mimic LSC and can develop concomitantly in patients with known LSC. If suspected LSC continues to grow despite treatment, a biopsy is always indicated.

Antihistamines and oral corticosteroids are frequently prescribed for the treatment of LSC but are unlikely to offer the patient any benefit.

A major pitfall in the treatment of LSC is failure to identify the primary driver of the patient’s scratch–itch cycle.

• Failing to adequately address a mental health disorder that may be leading to LSC impedes treatment success.

• In patients with OCD, significant depression, or anxiety, treatment success involves a multispecialty approach that may involve a psychiatrist, counselor, and primary care physician.
• Similarly, if the patient’s pruritus is driven by a primary skin condition, such as psoriasis or AD, it is essential to adequately treat the primary condition.

LSC can become superinfected. Skin lesions demonstrating signs of warmth, erythema, or discharge should be cultured and treated with either a topical or oral antibiotic.

Counseling

You have a condition called “lichen simplex chronicus.” This type of rash is usually caused by excessive scratching or rubbing of the same area of skin over time. This condition is frequently difficult to treat.

There are several things you should do to treat your rash. First, you have been prescribed a topical corticosteroid. Apply this to the affected area and then wrap the area with saran wrap to help get the medicine into the skin. If this is not feasible, apply a bandage over the prescription cream. Second, keep the area covered with a bandage at all times, even when you sleep. Lastly, apply a thick moisturizing cream to the area every time that it itches as many times as is necessary throughout the day.

If your rash fails to improve despite this therapy, we will re-evaluate it.

Keloids

Shivani Sinha, Gloria Lin, and Katalin Ferenczi

Clinical features

Keloids are characterized by an excessive growth of scar tissue in response to dermal injury; rarely, they have been reported to present spontaneously in patients prone to developing keloids. They are more commonly seen in younger, darker-skinned individuals, who may be genetically predisposed to developing these lesions. Their cosmetically disfiguring nature and lack of efficacious therapies can make this a challenging diagnosis because patients may be disappointed with the treatment outcomes.

• Given the prevalence of keloids, patients often self-diagnose this condition without the aid of a medical professional. They will complain of pruritus, tenderness, and enlargement of the lesions while relating a history of inciting cutaneous injury, including piercings, surgeries, vaccinations, burns, and acne.
• Keloids appear as smooth, shiny, flesh-colored to pink or red or hyperpigmented papules, plaques, or nodules, which are usually firm, rubbery, and can be pruritic or painful. They may present anywhere on the body but are often seen on the earlobes, chest, and back. The keloids may not appear until months after the cutaneous insult. Without intervention, progressive enlargement is possible because they are unlikely to regress on their own. Keloids may produce contractures, causing impaired function, which can be debilitating for the patient.

Differential diagnosis

The differential diagnosis for keloids include hypertrophic scars, dermatofibromas (DFs), dermatofibrosarcoma protuberans (DFSP), foreign body reaction, sarcoidosis, keloidal scleroderma, and lobomycosis.

• Hypertrophic scars are large, thickened scars that are confined to the wound borders, whereas keloids extend beyond it. They tend to appear quickly after the preceding trauma and can resolve. Keloids, on the other hand, may appear months later and are unlikely to improve without treatment.
• DFs are thought to arise in areas of trauma (i.e., shaving or arthropod bites) and are commonly seen in young females on the lower extremities, upper arms, and upper back. They present as firm, skin-colored or hyperpigmented papules or nodules, which can be pruritic or painful. On physical examination, DFs may have a positive dimple sign when squeezed because the skin will pucker inwards. Similar to keloids, these are unlikely to resolve on their own.
• DFSP is a locally aggressive soft-tissue sarcoma seen on the trunk or proximal extremities. DFSP appears as a firm, slow-growing plaque that becomes large and protuberant over time. Although this is a malignant condition, lymphatic or hematogenous metastasis is rare. Patients suspected of having a DFSP should be referred to a dermatologist for further evaluation and possible biopsy because it may require treatment with wide excision, Mohs micrographic surgery, radiation, and/or imatinib.
• A foreign body reaction may occur as a result of trauma and after implantation of foreign material in the skin and involves an inflammatory soft tissue response. It may appear as a painful, flesh-colored, erythematous, or hyperpigmented papule, nodule, or plaque at the site of injury. Referral to dermatology is recommended because the area may need to be biopsied or excised for diagnosis and therapy (to remove the foreign body).
• Sarcoidosis can mimic keloids because it can also occur at areas of trauma, injury, or pre-existent scars. Clinically, it can form hyperpigmented nodules that may be confused with keloids. On examination, compression of the lesion with a glass slide (diascopy) can demonstrate an apple jelly like appearance that is often associated with granulomatous processes. A biopsy will demonstrate sarcoidal granulomas.
• Keloidal scleroderma is a rare variant of scleroderma that presents with multiple hyperpigmented nodules or plaques that are localized to the upper trunk. Although these lesions clinically resemble keloids, they are nontender and lack a history of an inciting injury and the systemic symptoms that may be seen with scleroderma.
• Lobomycosis, also known as “keloidal blastomycosis,” is a fungal infection usually seen in more tropical areas, such as Central or South America. Chronic infection leads to the formation of nodules and plaques, whose growth and appearance resemble keloids. Treatment can be challenging, especially if there is widespread disease. A biopsy with special stains is often required to establish this diagnosis.

Work-up

This is usually a clinical diagnosis based on physical examination and history.

• The shape of the scar, growth progression, family history, and antecedent skin injury may support a diagnosis of keloid.
• If there is any uncertainty in the diagnosis, the patient should be referred to a dermatologist for further evaluation and treatment. A biopsy may be performed by a dermatologist to rule out serious skin conditions or malignancies that can mimic keloids.

Initial steps in management

The initial management of keloids is complex and often requires a combination of therapies. The most important step in management is to educate the patient on avoiding cutaneous injury and to discuss realistic treatment expectations.

• Advise against any further insult to the skin, including piercings, elective surgeries, and burns. Caution should be taken when shaving to avoid any injury. If the patient has an active underlying condition, such as acne, this should be treated to prevent further keloid formation.
• Recommend counseling the patient that the management goal is symptomatic relief (decrease pain and/or pruritus). There may be some aesthetic improvement; however, because there is scar tissue in the area, the skin cannot return to baseline. In addition, it is important to discuss that it will likely require multiple treatments to see maximum benefit. Many patients will often ask why the area cannot just be shaved down; thus it is important to discuss the high recurrence risk with this treatment method.