obsolete Microsporum nanum tinea capitis

Obsolete Description of Microsporum nanum Tinea Capitis

Microsporum nanum was previously considered a causative agent of tinea capitis, a fungal infection of the scalp characterized by scaling and patchy alopecia. However, it is now known that this organism is actually a variant of Nannizzia nana (previously Microsporum gypseum).

Characteristics

• Tinea capitis caused by Microsporum nanum was previously described as a disorder with a code of 403012004.
• The condition presented with localized alopecia and scaling, but may have included subtle findings of mild hair loss.
• It is now understood that this description refers to Nannizzia nana, which is a geophilic fungus pathogenic to humans and animals.

Reclassification

Microsporum nanum was reclassified as Nannizzia nana in 1954 by Fuentes et al. This change in classification reflects our current understanding of the dermatophyte species responsible for tinea capitis.

References

• [1] Fuentes, Aboulafia, and Vidal (1954) initially isolated a "dwarf form" of Microsporum gypseum from a case of tinea capitis, which they classified as M. gypseum var. nanum.
• [11] Nannizzia nana was first described in 1954 by Fuentes et al. in Cuba as the aetiological agent of tinea capitis in a child, identified as a dwarf form of Microsporum gypseum.

Note: The description of Microsporum nanum tinea capitis is now considered obsolete and has been replaced with the current understanding of Nannizzia nana as the causative agent.

Based on the provided context, here are the signs and symptoms of obsolete Microsporum nanum tinea capitis:

• Hair loss (alopecia): The presence of alopecia is a significant symptom of tinea

Diagnostic Tests for Obsolete Microsporum nanum Tinea Capitis

The diagnosis of tinea capitis, a fungal scalp infection, can be confirmed through various diagnostic tests. For the obsolete Microsporum nanum variant, the following tests were historically used:

• Microscopic Examination: A light microscopy examination using potassium hydroxide (KOH) prep and fungal culture was performed to confirm the diagnosis [3]. Samples of affected hair were placed on a microscope, and the small spores can be seen by focusing the microscope on the edge of the epilated hair shaft [6].
• Dermoscopy: Dermoscopy is a useful and non-invasive diagnostic tool that can aid in the diagnosis of tinea capitis [2]. However, it may not be sufficient to confirm the diagnosis.
• PCR Techniques: Molecular tests such as PCR techniques can be utilized to detect fungal DNA, providing an additional option for confirming the diagnosis [4].
• Macroscopic and Microscopic Colony Morphology: Dermatophyte identification was carried out based on macroscopic and microscopic colony morphology, urease activities, in vitro hair perforation test, growth at 25°C and 37°C, and other characteristics [9].

It is essential to note that the diagnosis of tinea capitis can be challenging, and a combination of clinical presentation, laboratory tests, and dermatological expertise may be necessary for an accurate diagnosis.

References:

[1] Fuentes, Aboulafia, and Vidal (1954) - First described Microsporum nanum as M. gypseum var. nanum [11]. [2] AKC Leung (2020) - Dermoscopy is a useful diagnostic tool for tinea capitis [2]. [3] FD Pratiwi (2020) - Light microscopy examination using KOH prep and fungal culture was performed to confirm the diagnosis [3]. [4] May 24, 2022 - PCR techniques can be utilized to detect fungal DNA [4]. [6] Microsporum nanum small spores can be seen by focusing the microscope on the edge of the epilated hair shaft [6]. [9] Dermatophyte identification was carried out based on macroscopic and microscopic colony morphology, urease activities, in vitro hair perforation test, growth at 25°C and 37°C, and other characteristics [9].

Treatment Options for Obsolete Microsporum nanum Tinea Capitis

Historically, the treatment of choice for Microsporum nanum tinea capitis has been Griseofulvin. However, with its unavailability in some countries, including New Zealand, alternative treatments have emerged.

• Griseofulvin: Although no longer widely used due to its unavailability, Griseofulvin was previously the most effective treatment for Microsporum nanum tinea capitis [2]. A combination of Griseofulvin 1x375 mg and ketoconazole 2% shampoo twice weekly has been shown to be effective in treating this condition [7].
• Itraconazole: Although not FDA-approved for use in children or for tinea capitis, accumulating evidence supports its effectiveness and safety for this condition [4]. A 30-d course of 100 mg of itraconazole daily has been shown to effectively treat tinea capitis [1].
• Terbinafine: This allylamine antifungal medication can be administered orally or topically as a cream. The treatment of choice for localized infection is terbinafine cream twice daily for 2 weeks or an imidazole twice daily for 4 weeks [5].

It's essential to note that the mainstay of treatment for tinea barbae, which is caused by Microsporum canis (not Microsporum nanum), is oral antifungal therapy. Topical agents can be used as adjunct therapy [3].

The differential diagnosis for obsolete Microsporum nanum tinea capitis involves considering various conditions that may present with similar symptoms. According to the available information, some common human diseases caused by Microsporum nanum include:

• Tinea capitis
• Tinea corporis
• Tinea cruris
• Tinea faciei

These conditions are characterized by fungal infections of the skin, and their symptoms might include alopecia, pruritus, scale, and posterior cervical lymphadenopathy. However, it's essential to note that the presence of these symptoms does not necessarily confirm the diagnosis of Microsporum nanum tinea capitis.

Other conditions that should be considered in the differential diagnosis for obsolete Microsporum nanum tinea capitis include:

• Seborrheic dermatitis
• Atopic dermatitis
• Alopecia areata
• Folliculitis
• Psoriasis

These conditions can present with similar symptoms, such as inflammation, scaling, or alopecia of the scalp. Therefore, a comprehensive evaluation and diagnostic workup are necessary to accurately diagnose obsolete Microsporum nanum tinea capitis.

According to [5], examples of some common human diseases caused by Microsporum nanum include tinea capitis, tinea corporis, tinea cruris, and tinea faciei. This information highlights the importance of considering these conditions in the differential diagnosis for obsolete Microsporum nanum tinea capitis.

Additionally, [7] states that dermatophytic infections can be caused by various fungi, including Trichophyton or Microsporum genera. This information emphasizes the need to consider the specific causative agent when diagnosing and differentiating between these conditions.

References:

[5] Examples of some common human diseases caused by Microsporum nanum including tinea capitis, tinea corporis, tinea cruris, and tinea faciei. [7] Dermatophytic infections can be caused by: · Tinea capitis is due to fungal infection by dermatophyte of Trichophyton or Microsporum genera.