Rickettsialpox - Causes, Symptoms, and Treatment

Introduction

There are a lot of microbial infections affecting human beings in various ways. Rickettsialpox is an infection that is induced by a specific bacterial species from the Rickettsia genus. It is reported to be most prevalent in the United States. Apart from the United States, rickettsialpox is widely reported in other countries like Korea, Croatia, and South Africa. However, the incidence (new cases) rate drastically decreased with the introduction of proper mice control strategies like pesticides.

What Is Rickettsialpox?

Rickettsialpox is one among the wide category of rickettsial infections inflicted by a specific species of Rickettsia. The disease take the form of fever with extensive spotting over body surfaces, hence it comes under the category of spotted fever. Humans generally acquire the disease-causing microbe of rickettsialpox from animals like mites, therefore these are medically known by the term vector-borne diseases.

What Causes Rickettsialpox?

• Rickettsial Akari is the rickettsial species that is specifically responsible for the disease rickettsialpox. These bacterias generally reside and inhabit the gut (stomach) of certain mouse mites, which is scientifically known by the name Liponyssoides sanguineus.

• These mites do not create any health issues or disease conditions in the mouse. But once they get access into a human body by chance, then it gives rise to the formation of typical skin rashes all over the body, excluding the palms and soles.

• The rashes simulate chicken pox, and hence named thus. Apart from mites, Rickettsial Akari is also reported to be encountered in certain cats and dogs.

• Unlike other rickettsial species, it does not focus on the blood vessel cells instead it aims specifically at the macrophages - CD68 macrophages. The exact mechanism with which it influences the macrophage is still under discussion and yet to be figured out. Later it extends further into the spaces in between cells and manifests in the form of various symptoms.

What Is Rickettsia?

Rickettsia is a typical bacterial genus that encompasses various rickettsial species, which is capable of producing a spectrum of infections that are widely known by the name rickettsial infections. The bacterial species in rickettsia are further graded into different classes, namely, spotted fever group, typhus group, and others. The majority of the rickettsial bacteria act by disrupting the blood vessel walls and exhibit a similar pattern of destruction in the human body. Rickettsial infections in humans are always the result of an accidental encounter with the bacterial species. Ticks, mites, fleas, and lice are agents that bring about rickettsial infections in humans through their bites. Symptoms exhibited by these bacterial groups are more or less similar.

What Are the Symptoms Associated With Rickettsialpox?

Rickettsialpox is a symptomatic rickettsial disease with obvious signs and symptoms. Some of the key features exhibited by rickettsialpox include the following:

• Fever: A moderate degree of fever is elicited in rickettsialpox infection. Occasionally fever is accompanied by chills, cold and runny nose.

• Rashes: Chickenpox-like rash is a peculiar and unique feature of rickettsialpox. Frequently rashes tend to appear a couple of days after the onset of the infection. Rashes initially develop as flat pigmented areas, later bulge out forming a vesicular structure (papulovesicular), and eventually rupture giving rise to deeply crusted areas. The pattern and nature of the skin rash tend to simulate chickenpox lesions. Rashes persist for over a couple of weeks and later resolve without leaving any markings on the skin.

• Eschar: It clearly demarcates the area where the mite bites. It is quite dark in color and appears flaky and dry.

• Headache: Rickettsialpox frequently elicits headaches. Headaches are often accompanied by muscle pain all over the body.

• Photophobia: Certain patients exhibit challenges in tolerating bright light and develop extreme reactivity and responsiveness towards it.

• Lymphadenopathy: Just like other infectious diseases, rickettsialpox also projects the bulging of nodes, indicating the presence of infection.

• Gastrointestinal Issues: Occasionally, gastrointestinal (GI) issues like vomiting are encountered along with rickettsialpox. General GI upset indicates an ongoing active infection in the body.

• Cough: Though rare, certain patients elicit cough as well.

How Is Rickettsialpox Diagnosed?

Detailed analysis of the clinical findings and medical history clears the path of diagnosis. History of mite bite or susceptibility to mouse mites often aids in the diagnosis. Classic symptoms like rash, eschar, and associated fever facilitate diagnosis. However, the diagnosis is confirmed with the help of certain investigatory tests and procedures. Some routinely advised tests include the following:

• Blood Test: It often projects a significant hike in the number of white blood cells (leukocytosis), indicative of ongoing infection in the body. At the same time, platelet count reveals a drastic reduction (thrombocytopenia). In addition, certain electrolytes like sodium levels also collapse. Serum proteins like albumin levels deviate from their normal range. However, at times, the blood picture appears normal, even in the presence of infection. Therefore blood tests alone cannot be considered as a reliable diagnostic test for rickettsialpox.

• Indirect Immunofluorescent Assay (IFA): It is one of the widely advised tests for rickettsialpox infections as it aids in the confirmation of the diagnosis by specifically recognizing the rickettsial antibodies (IgG, IgM) in the serum.

• Polymerase Chain Reaction (PCR): It is an extensively advised test to expose the microbial genetic material (gene). PCR works by amplifying the genetic substance and thereby facilitating bacterial recognition.

• Biopsy: It is routinely advised for all rickettsial infections. Biopsy often aids in arriving at the final diagnosis. Generally, a biopsy specimen is collected from the bite area where eschar is formed.

What Are the Different Treatment Interventions Available for Rickettsia pox?

Rickettsialpox conventionally resolves by itself within a few weeks without any interventions and is self-limiting. However if it remains for a longer period, then appropriate treatment strategies need to be considered. As it is a bacterial infection, antibiotic therapy works well for rickettsialpox. It is the widely recognized and accepted treatment approach for enhancing the resolution of rashes and thereby enhancing and hastening the recovery process. Among antibiotics, Doxycyclin is the most appropriate medicine for tackling rickettsia infection. Tetracycline and Chloramphenicol are also advised in certain patients who cannot tolerate Doxycycline.

Conclusion

Rickettsialpox is one of the rickettsial diseases that humans acquire from the bite of a mouse mite. It is conventionally not a problematic condition and frequently settles by itself. Hence it does not necessitate treatment all the time. In case the condition persists, then simple antibiotic therapy is advised to deal with it effectively. Most of the time, it resolves without giving rise to any complications.