Plica Polonica Secondary to Pediculosis Capitis and Use of Shampoo.

Sir,

A 21-year-old female presented with itching on the scalp and entangled mass of hair which was difficult to comb since the past 1.5 months. She used itraconazole shampoo as advised by local physician, which further worsened the condition. There was no history of the use of high-temperature processing devices, chemical hair treatment, or any drug intake.

On scalp examination, firm mass of entangled hair resembling “bird's nest” was present, mainly involving the occipital and parietal are [Figures 1 and 2]. Separation of the hair strands was not possible. On closer examination, nits were presently diffusely over the scalp and lice could be visualized suggesting pediculosis capitis. There was no associated redness, oozing, or crusting on the scalp. Rest of the dermatological and systemic examination was unremarkable. Based on the history and clinical findings, diagnosis of plica polonica associated with pediculosis capitis was made. The patient was advised cutting of matted hairs followed by application of topical permethrin 1% to be repeated after an interval of 10 days.

Figure 1

Mass of dense matted hair resembling a “bird's nest”

Figure 2

Right lateral view showing irreversibly matted scalp hair

Plica polonica is a rare condition characterized by diffuse matting of hair with irregular twists and irreversibly entangled plaits, which are firm to hard impenetrable mass of keratin cemented together with dirt and exudates.[1] The condition was prevalent in Poland in the 19th century, hence the name plica polonica or Polish plait.[1] The exact mechanism of matting is not known. It has been compared to the physical phenomenon of felting of wool where exposure to friction and compression causes compaction of fibers.[1] Similarly, vigorous friction and frequent use of harsh shampoos and cleansers cause longitudinal splitting and weathering of the hair shaft. Hair shafts have a potential to get dielectrically charged as rubbing of hair toward the scalp produces positive charge and rubbing of hair toward the tip produces negative charge. Due to this property, electrostatic attraction could develop between adjacent hair shafts resulting in matting.[2] Other predisposing factors are lack of proper care of long hair or its neglect resulting in infection and infestations of scalp hair, psychiatric disturbances, chemical hair processing, and chronic illness and due to religious reasons as seen in “Sadhus” in the form of dreadlocks.[23] Rare case reports of plica polonica in pediatric age group and its association with rupoid psoriasis and chemotherapeutic drugs such as methotrexate and azathioprine have also been reported.[2]

In our patient, poor hygiene was the most likely factor as evidenced by the presence of pediculosis capitis predisposing to the development of plica polonica. In addition, the use of anti-dandruff shampoo by the patient further aggravated the condition. This could have been prevented by the use of hair care measures such as regular cleaning of hair with mild cleansers, gentle oiling and combing to avoid entangling, and treatment of the underlying condition. Manual separation using organic solvents can be tried in early cases.[4] This can help in avoidance of cutting or trimming of hair, the only feasible treatment at later stages, as had to be advised in our case. Therefore, early diagnosis, identification of the underlying cause, and appropriate treatment of the condition are necessary.

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