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Year : 2000  |  Volume : 66  |  Issue : 4  |  Page : 182-184

The Blue Neck Syndrome : Nematode Larvae in Skin Scrapings

Correspondence Address:
P Sugathan

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Source of Support: None, Conflict of Interest: None

PMID: 20877070

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A novel non-inflammatory type of pigmentation of the neck associated with nematode larvae on affected skin is described. The name 'Blue neck syndrome' is suggested for this condition because of the characteristic clinical appearance. Antinematode agents such as albendazole and neem oil have been found to be effective in the treatment.

Keywords: Blue neck syndrome, Pigmentation of neck, Nematode larvae, Albendazole, Neem oil

How to cite this article:
Sugathan P, Jayaram CP. The Blue Neck Syndrome : Nematode Larvae in Skin Scrapings. Indian J Dermatol Venereol Leprol 2000;66:182-4

How to cite this URL:
Sugathan P, Jayaram CP. The Blue Neck Syndrome : Nematode Larvae in Skin Scrapings. Indian J Dermatol Venereol Leprol [serial online] 2000 [cited 2018 May 27];66:182-4. Available from: http://www.ijdvl.com/text.asp?2000/66/4/182/4914

  Introduction Top

Pigmentation of the skin of -the neck is a common condition. It is usually asymptomatic and therefore is not considered important, except for its cosmetic concern. It is generally accepted as a reaction to the gold or the chains worn around the neck by all women and many men. It is only when the pigmentation deepens or is associated with itching or other symptoms that medical help is sought. The condition, particularly in the obese, is often diagnosed as pseudoacanthosis nigricans and treated empirically.

Pseudoacanthosis nigricans is characterized by hyperpigmentation of thickened velvety skin, the pigmentation involving both the surface as well as the depths of skin folds. We observed many patients in whom the pigmentation was confined to the skin's surface, sparing the depth of the skin folds. The diagnoisis of pigmented tinea versicolor was considered and KOH mounts of skin scrapings were examined.These showed instead of pityrosporum, what appeared to be nematode larvae [Figure - 1].

Patients in whom larvae were demonstrated in the skin scrapings constituted a separate group with distinctive pigmentation of the surface, the skin folds clearly visible as nonpigmented grooves. The affected skin had a dull dry matt surface with a characteristic bluish black colour, which made us call this the 'Blue neck syndrome'. Pigmentation was commonest over the back of the neck, less often along its sides and rare in front [Figure - 2] and [Figure - 3].

Intrigued by these unexpected findings we began a study of such patients, the results of which are presented in this paper.

  Subjects and Methods Top

The patients studied were those seen in the Dpartment of Dermatology, Baby Memorial Hospital, Kozhikode or in the consulting room of the first author, in whom pigmentation of the skin of the neck was noticed. They included patients presenting with neck pigmentation as the primary complaint as well as others with unrelated complaints but in whom neck pigmentation was noticed incidentally.

After detailed history, clinical examination and in some, routine blood and stool tests, those willing were subjected to skin scrapings for KOH mounts.

No controls were tested initially but towards the later part of the study a total 50 skin patients and healthy subjects with no neck pigmentation were used as controls for KOH mount examination. Biopsy of the affected skin was perfomed in 3 subjects consenting to the procedure.

On the assumption that the nematodes could be responsible for the pigmentation, empirical treatment was started with albendazole (zentel) twice daily orally for one week along with 10% suspension of albendazole in calamine lotion applied locally at bed time for 2 or 3 weeks. As this was expensive a more economical regime with neem oil (Azadirachta indica) applied locally for 3 weeks or more was substituted, in thsoe who could not afford albendazole.

  Results Top

From February 1998 to February 2000 a total of 601 patients with neck pigmentation were tested by KOH mounts. Of them 456 were positive for nematodes. The nematode positive persons were nearly equal in sex distribution (male 320, female 281). They were of all ages, young children, adolsecents and adults, with mean age of 35 years. In body build they ranged from lean to obese. They belonged to all strata of society from poor to the rich, with a number of prfessionals including doctors represented. The duration of the condition in them varied from 15 days to 28 years. Significant eosinophilia or parasitic cysts or ova were not observed in those tested.

The nematodes observed were not all uniform in morphology. The commonest form was greyish­yellow in colour measuring approximately 200 microns in length and 6 to 8 microns in width at its broadest part, and with a tapering tail. Internal structures resembling intestines could be seen. Attempts to identify their species have not so far been successful.

The results of treatment with albendazole were very satisfactory. With few exceptions, the pigmentation faded in intensity and in some, even disappeared completely weeks after the treatment. Treatment with neem oil was also effective though it took much longer for pigmentation to fade. In a small number, the pigmentation recurred after some months and in a few, nematodes could also be demonstrated in repeat scrapings. They also responded to repeat treatment on the same lines (Exact numbers are not given due to incomplete documentation).

  Discussion Top

These observations, admittedly preliminary in nature, are presented for the following reasons: No such appearance has been reported in skin scrapings so far. Nematodes are not recognized as resident or casual members of normal skin flora. In this study also nematodes were not observed in the scrapings in any of the 50 controls examined.

All known nematode lesions of the skin, such as creeping eruption, are inflammatory in nature and the worm is within the skin. In this condition the nematodes are on the skin and no inflammatory changes were seen either clinically or histologically in any patient. It is possible that the pigmentation, as well as itching seen in some patients, could be due to hypersensitivity to nematode antigens. Pigmentation in the dirty neck syndrome' has also been considered due to hypersensitivity, but no nematode or other parasitic or fungal agent has been associated with this.[3]

Beneficial effects observed uniformly after treatment with oral and local albendazole as well as with neem oil, both of which are known anti­nematode agents appear to support the possibility that 'Blue neck syndrome' is nematode-induced. Absence of nematodes in skin scrapings from controls, as well as the reappearance of the nematode during recurrence of pigmentation supports this hypothesis.

A major difficulty has been failure to identify the nature of the nematode so far. One reason could be the very small number present in the lesion. The morphology of the mouth parts, reportedly critical in identification could not be studied as very often they were damaged by scraping and by KOH activity. Efforts are now on to establish identification of the nematode by cultures, with the help of nematologists.

  Conclusions Top

'Blue neck syndrome' is very common in this area (Northern Kerala) and presumably in other areas with similar climatic conditions as well. The fact that we could examine over 600 patients in 2 years testifies to this. The apparent cure with anti­nematode agents by oral and local treatment will be of interest to other dermatologists who may be seeing such patients.

These observations are presented for their novelty and in the hope that they may prompt dermatologists elsewhere to comment on and verify our findings.

  References Top

1.Elder D, Elenitsas R, Johnson Jr B, et al. Parasitic infestations of the skin. In: Elder D. Editor in chief. Lever's Histopathology of the Skin, 8th Edition, Philadelphia, Lippincott-Raven, Publishers. 1997; 559-568.  Back to cited text no. 1    
2.Pasyk K. Dermatitis rhabditidosa in a 11-year-old girl: a new cutaneous parasitic disease of man. Br J Dermatol 1978; 98: 107-ss­111.  Back to cited text no. 2  [PUBMED]  
3.Colver GB, Mortimer PS, Millard PR, et al. The 'Dirty neck' - a reticulate pigmentation in atopics. Clin Experiment Dermatol 1987; 12: 1-4.  Back to cited text no. 3  [PUBMED]  


[Figure - 1], [Figure - 2], [Figure - 3]


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