Key Concepts: Idiopathic Eruptive Macular Hyperpigmentation
Idiopathic eruptive macular hyperpigmentation constitutes a pigmentary disorder benign and is rare, typically manifesting during the first two decades of life. It is characterized by the appearance of hyperpigmented macules asymptomatic, presenting a predisposition. notable predilection for the upper body areas [1]. This condition is classified as a variation of acquired dermal macular hyperpigmentation. dermal acquired.
For better visual understanding, consult the images of acquired dermal macular hyperpigmentation.
Population Affected by Idiopathic Eruptive Macular Hyperpigmentation
Although idiopathic eruptive macular hyperpigmentation can occur in any age group and affects both sexes equally, most reported cases tend to develop or develop in childhood and adolescence [2].
Etiology: What Causes Idiopathic Eruptive Macular Hyperpigmentation?
The specific cause of idiopathic eruptive macular hyperpigmentation remains unknown. The hypermelanosis arises sporadically, without being associated with previous illnesses, inflammation, sun exposure, or medication administration [3]. Nor has a family history been documented for this disorder [4]. fever for this disorder [4].
In rare cases, it has been speculated that hormonal changes could play a role, particularly in those patients whose condition worsened during pregnancy [4].
Clinical Manifestations of Idiopathic Eruptive Macular Hyperpigmentation
The hallmark of idiopathic eruptive macular hyperpigmentation is the presence of multiple macules ranging from grayish-brown to black. These can be small and discrete, or extend into larger patches, but they are always asymptomatic.
- The Pigmentation The pigmentation is most frequently located on the face, neck, trunk, and proximal extremities in Sneddon syndrome, affecting the trunk and back; the extremities are rarely involved.. The mucosal surfaces Mucosal, Sweet's hair, , and nail, the palms of the hands, and the soles of the feet remain intact.
- The size of the Lesion generally does not exceed 10 mm in diameter, ranging between 0.5 and 2.5 cm [1,2].
- The macules lack scaling and are not scaly [5]. scaly [5].
- There is a variant characterized by plaques elevated plaques with a velvety texture, known as idiopathic eruptive macular hyperpigmentation with papillomatosis [5]. papillomatosis [5].
- No history of erythema prior to onset is observed.
- The pigmentation tends to resolve spontaneously over a period of months or years.
It is important to note that idiopathic eruptive macular hyperpigmentation is not exacerbated by exposure to UV (ultraviolet) radiation [2]. UV (ultraviolet) [2].
Histology of Idiopathic Eruptive Macular Hyperpigmentation
The analysis Histopathology, performed via a skin biopsy, biopsy reveals the following findings:
- Increased pigmentation in the basal cellular layer of the epidermis. epidermal cell malignant. Among the dermatological neoplasms it helps to identify with precision are:.
- Epidermal papillomatosis is observed.
The management of idiopathic eruptive macular hyperpigmentation is usually conservative due to its self-limiting nature and benign behavior. Clinical follow-up is essential to rule out other causes of hyperpigmentation in young patients.
- It is rarely observed in the variant form.
- Dermal melanophages and pigmentary incontinence despite the absence of basal layer damage or dermal lichenoid inflammation, which constitutes a controversial feature, as some consider it an exclusion criterion. [5]
- A sparse number of mast cells excludes cutaneous mastocytosis.
Diagnostic Criteria for Idiopathic Eruptive Macular Hyperpigmentation
The diagnostic criteria were originally established by Sanz de Galeano [6]. These include:
- Appearance of discrete, non-confluent, brownish-black, asymptomatic macules located on the neck, trunk, and proximal extremities in children and adolescents.
- Presence of hyperpigmentation in the basal cells of the epidermis along with the presence of dermal melanophages, provided there is no damage to the basal cells or lichenoid infiltrate.
- Absence of previous inflammatory lesions.
- No history of drug exposure.
- Normal mast cell count.
Subsequently, modifications have been suggested that incorporate clinical features such as the possible presence of slightly elevated plaques reminiscent of acanthosis nigricans, facial involvement, and histology described as epidermal hypermelanosis with or without papillomatosis, even in the absence of dermal inflammation [1].
A global consensus statement issued in 2019 expanded the criteria, specifying that the pigmented macules must not have appeared after a known episode of viral exanthem, pityriasis rosea, drug eruption, or other similar conditions [7].
Differential Diagnosis of Idiopathic Eruptive Macular Hyperpigmentation
Clinically, idiopathic eruptive macular hyperpigmentation can be confused with several skin pathologies. It is essential to distinguish the condition based on the following alternatives:
- Other forms of acquired dermal macular hyperpigmentation: such as lichen planus pigmentosus and erythema dyschromicum perstans. The key differences lie in the affected age group, the size and distribution of the lesions, and the natural evolution of the condition [5].
- Fixed drug eruption: characterized by recurrences associated with the specific intake of a certain medication.
- Post-inflammatory hyperpigmentation: this sequela always appears after a skin lesion or a previous inflammatory episode on the skin.
- Maculopapular cutaneous mastocytosis: this condition presents with pruritus, and the lesions may show erythema upon rubbing (or even blister in pediatric patients). Histology reveals an excessive number of mast cells.
- Café-au-lait macules: distinguished by their light brown color and the absence of spontaneous resolution.
- Acanthosis nigricans: this condition is associated with clinical manifestations related to insulin resistance or malignancy [1–3].
Treatment of Idiopathic Eruptive Macular Hyperpigmentation
Generally, idiopathic eruptive macular hyperpigmentation does not require active treatment, as the lesions are asymptomatic and resolve spontaneously over a period ranging from several months to a few years. After resolution, no sequelae or residual scars remain [1]. To date, recurrence of the condition has not been reported.
