Surreal digital illustration of diverse skin textures.

Uncommon Skin Conditions: What You Need to Know About Granulomas and Protothecosis

Nico Varela in Health & Wellness December 2025 • 4 min read.

"A closer look at rare dermatological cases, effective treatments, and what to watch for."

Skin conditions come in many forms, some of which are quite rare and can present diagnostic and treatment challenges. This article sheds light on two such uncommon conditions: papular elastolytic giant cell granuloma and disseminated protothecosis. Understanding these conditions is crucial for early detection and effective management.

Papular elastolytic giant cell granuloma is a rare dermatological condition characterized by the appearance of small, raised bumps (papules) or coalescing plaques on the skin. These lesions often exhibit a loss of elasticity due to the destruction of elastic fibers in the skin. While the exact cause remains unclear, various treatments have been explored, as highlighted in a review of reported cases.

Disseminated protothecosis, on the other hand, is an exceedingly rare infection caused by Prototheca species, a type of achlorophyllous algae. Unlike typical algae, Prototheca lacks chlorophyll and can cause opportunistic infections, particularly in individuals with compromised immune systems. This condition can manifest as rapidly progressing skin ulcers and requires aggressive treatment with antifungal agents.

Papular Elastolytic Giant Cell Granuloma: Understanding the Condition and Treatment Options

Surreal digital illustration of diverse skin textures.

Papular elastolytic giant cell granuloma is a skin condition that primarily affects adults, with a slight predilection for males. The condition is characterized by the appearance of discrete papules or confluent plaques, typically on the trunk and arms. These lesions often lack the characteristic annular (ring-shaped) appearance seen in other granulomatous conditions.

The coexistence of annular lesions can sometimes occur, adding complexity to the diagnosis. Complications associated with papular elastolytic giant cell granuloma may include metabolic disorders such as impaired glucose tolerance and diabetes mellitus, as well as other systemic conditions like hypertension and anxiety disorders.

Topical Corticosteroids: Variable efficacy, with some cases showing no improvement.
Oral Corticosteroids: Limited success, although some improvement has been reported in certain cases.
Other Therapies: Intralesional corticosteroids, hydroxychloroquine, quinacrine, tranilast, narrow-band ultraviolet B (UVB) irradiation, and topical tacrolimus have been used with varying degrees of success.

A study reviewing multiple cases indicated inconsistent responses to topical and oral corticosteroids. Alternative treatments such as hydroxychloroquine and topical tacrolimus have shown promise in some individuals. Narrow-band UVB irradiation has also been reported as effective in one case. Spontaneous regression, though rare, has been observed in some instances, highlighting the unpredictable nature of this condition.

Protothecosis: A Rare Algal Infection

The successful management of disseminated protothecosis relies on early diagnosis and aggressive antifungal therapy, typically with amphotericin B. Protothecosis is an exceedingly rare infection caused by Prototheca species, achlorophyllous algae found ubiquitously in nature. It is classified into three forms based on clinical manifestations: cutaneous, olecranon bursitis, and disseminated. Disseminated protothecosis requires aggressive treatment with antifungal agents.

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Everything You Need To Know

What exactly is papular elastolytic giant cell granuloma, and what are its primary symptoms?

Papular elastolytic giant cell granuloma is a rare skin condition characterized by small, raised bumps (papules) or merging plaques on the skin. These lesions are notable for their loss of elasticity, which results from the destruction of elastic fibers within the skin. Although the exact cause is not entirely clear, it primarily affects adults and has a slight predilection for males. The lesions typically appear on the trunk and arms and don't always exhibit the annular, or ring-shaped, appearance common in other granulomatous conditions. The coexistence of annular lesions can complicate the diagnosis.

What treatment options are available for papular elastolytic giant cell granuloma, and how effective are they?

Treatment options for papular elastolytic giant cell granuloma include topical corticosteroids, oral corticosteroids, intralesional corticosteroids, hydroxychloroquine, quinacrine, tranilast, narrow-band ultraviolet B (UVB) irradiation, and topical tacrolimus. The efficacy of these treatments varies considerably. Topical and oral corticosteroids often show inconsistent results, with some cases showing no improvement. Alternative treatments like hydroxychloroquine and topical tacrolimus have shown promise in some individuals, while narrow-band UVB irradiation has been effective in isolated cases. Spontaneous regression, though rare, can occur, highlighting the unpredictable nature of the condition. More research is needed to establish consistent and effective treatment protocols.

What is disseminated protothecosis, and what makes it such a rare and challenging infection to treat?

Disseminated protothecosis is an exceedingly rare infection caused by Prototheca species, a type of achlorophyllous algae, meaning it lacks chlorophyll. Unlike typical algae, Prototheca can cause opportunistic infections, especially in individuals with compromised immune systems. This condition can manifest as rapidly progressing skin ulcers and is classified into cutaneous, olecranon bursitis, and disseminated forms based on clinical presentations. Its rarity and the need for aggressive antifungal therapy, typically with amphotericin B, make early diagnosis and treatment critical for successful management. Further complicating treatment is the alga's ubiquitous presence in the environment, making complete avoidance challenging.

Are there any systemic conditions or complications associated with papular elastolytic giant cell granuloma that patients and doctors should be aware of?

Yes, complications associated with papular elastolytic giant cell granuloma may include metabolic disorders such as impaired glucose tolerance and diabetes mellitus, as well as other systemic conditions like hypertension and anxiety disorders. The coexistence of annular lesions can add complexity to the diagnosis. Patients diagnosed with papular elastolytic giant cell granuloma should be screened for these potential comorbidities to ensure comprehensive management and treatment.

How is disseminated protothecosis typically diagnosed, and what is the standard approach to treatment given its severity?

Disseminated protothecosis is typically diagnosed through clinical presentation combined with laboratory tests to identify Prototheca species in affected tissues. Given its severity, the standard approach to treatment involves aggressive antifungal therapy, most commonly with amphotericin B. Early diagnosis is crucial, as delayed treatment can lead to poorer outcomes. Because disseminated protothecosis primarily affects individuals with compromised immune systems, addressing the underlying immune deficiency is also a critical component of the overall treatment strategy. Additional research is needed to refine treatment protocols and improve outcomes for this rare and challenging infection.