What we are seeing here is diffuse alopecia due to transient hypothyroidism in a person technically suffering from hyperthyroidism. It would, therefore, be valid to mention them, although such changes will seldom be associated with hair loss. There are everyday causes of colour change including a change to green following swimming in, or shampooing with, water high in copper ions from copper piping. Yellowing at the front is common in heavy smokers and can be attributed to tar vapours. Dithranol and chrysarobin stain light-coloured or grey hair mahogany brown.
Chloroquine interferes with pigment synthesis affecting the colour of blonde or red hair.
After three to four months of treatment the hair becomes white or silvery. Mephenesin causes pigmentary loss in dark-haired individuals. Hydroquinone and phenylthiourea both interfere with tyrosine activity causing hypopigmentation of the hair and skin. Lightening of hair colour from black to brown may also occur in extreme iron deficiency. This list is by no means comprehensive but other reactions to drug therapy are much rarer.