Response to the article, ‘Pellagra in a woman using alternative remedies’

stretching or compression of the lateral femoral cutaneous net^e in the fascia lata or on the nerve root at the intervertebral foramen. Another pattern of identical pruritus involves tlie skin on the back of the shoulder, concentrating mainly in the scapular and interscapular areas and corresponding to dermatomes C5-6 and T1-3. Brachioradial pruritus involves the skin of the lateral cutaneous nerve, which predominantly emerges from the Tifth cervical nerve root. There is a marked similarity between these three patterns. All present with an itch of variable intensity ranging from vague tinghng through to severe maddening pruritus necessitating fierce and traumatic scratching. Generally there is little to see on examination although the latter form is often associated with excoriation and bruising. In the late stages on the litnbs there may be some hair loss and faint discoloration whereas on the back the skin may appear to be slightly thickened with a degree of melanosis. The pattern of nerve impulses produced by nerve trunk compression depends upon the degree of compression and the resultant sensation extends through paraesthesia to prickling, pruritus and finally pain. Mow environmental faetors, such as wind and sun, produce this symptom is enigmatic. Alternate pathways for sensory disturhanee from cold, heat and ultraviolet (UVR) damage through the neural components of the skin demand further investigation. An alternative explanation for the predominance of left-sided symptoms previously reported is the relative weakness of the muscles in the left shoulder girdle in right-handed populations, dragging on the cervical nerve roots. In the case presented, ehronic UVR exposure is unlikely to be a predisposing factor as the symptoms were all related to the left side rather than the right which would be expected to have received more sun exposure through driving. The left-sided symptoms eould, however, be explained by nerve compression. As each of these unusual pruritic syndromes involve specific dermatomes, I propose that a primary neural aetiology should be accepted and accorded an appropriate connotation, neuropathic pruritus, until such time as an alternative explanation may be provided.