John Almeyda

EFFECT OF PLASTIC OCCLUSIVE DRESSINGS ON PSORIATIC EPIDERMIS

SUMMARY.— Serial biopsies have been performed on psoriatic lesions from the forearm in 13 patients in whom the lesions were occluded with plastic occlusive dressings for 2 weeks, and in 13 control psoriatic subjects.

DRUG REACTIONS XVI

Many drugs may produce an eruption which is indistinguishable from or very similar to lichen planiis. The mechanism for its production is unknown. There is no evidence that it has an immunological basis. When the lesions clinically resemble lichen planus, often the histological picture is also that of lichen planus. In some instances however one observes a moderate degree of parakeratosis or an admixture of eosinophils in the cellular infiltrate, neither of which is encountered in lichen planus (Wilson, 194:6). Lichenoid eruptions, although in many instances mimicking exactly idiopathic lichen planus, frequently show atypical features such as marked scaling, eczematization, hypertrophic lesions, and a tendency to more intense residual hyperpigmentation. Mucous membranes may be involved, although frequently they are spared. If hair fall occurs it may be severe, and permanent. Anhidrosis may follow the eruption vnth atrophy of the dermal portion of the sweat gland (Sulzberger et al., 1947). Lichenoid drug eruptions may be differentiated from lichen planus in that they follow recent medication and discontinuation of the drug usually leads to clinical improvement. On occasions, once the rash has subsided following drug withdrawal, provocation by readministering the drug may reproduce the eruption.

Ancient schwannoma masquerading as parotid pleomorphic adenoma

Pleomorphic adenoma of the parotid gland is common. We report a typical case of a parotid gland swelling which clinically, radiologically and cytologically represented a pleomorphic adenoma. Only following surgical excision and histological examination however, was the true diagnosis of ancient schwannoma made. Benign peripheral nerve sheath tumours should always be considered in the differential diagnosis of parotid gland tumours.

Drug induced changes in pigmentation

Increased or decreased pigmentation may occur in the skin and its appendages. It may be due to many factors, including inflammation, or may accompany or follow certain skin diseases, such as hchen planus and leprosy. These pigmentary changes may be localized or generalized, and their degree is considerably dependent on racial factors. Drugs may also cause changes in pigmentation, most commonly an increase. It may be difficult to deflne whether the drugs, or the conditions for which they are given, are mainly responsible for the change. The colour of normal skin is due mainly to four pigments, namely oxyhaemoglobin, reduced haemoglobin, melanin and carotene. Several mechanisms are involved in drug induced changes in pigmentation of the skin; for example, heavy metals are deposited diffusely in the dermis bringing about a change in colour as a result of a Tyndall effect (optical changes in the refraction and scattering of incident light). Some elements, for example arsenic, cause colour changes by altering melanin deposition. Other drugs, for example dapsone, produce changes by combining with haemoglobin to form methaemoglobin. The fixed drug eruption produces localized increased pigmentation as a postinflammatory effect by increasing melanin deposition. Many drugs produce pigmentary changes by unknown mechanisms.

Malignant otitis externa in HIV and AIDS

Malignant otitis externa is a necrotising infection of the external ear canal which may spread to include the mastoid and petrous parts of the temporal bone, leading to skull base osteomyelitis. It is almost exclusively caused by infection with Pseudomonas aeruginosa, and usually occurs in elderly non-insulin-dependent diabetic patients. However isolated cases have been reported in a small number of non-diabetic patients, particularly in children who are immunocompromised due to malignancy, malnutrition and severe anaemia. In 1984 a case of malignant otitis externa was reported in a child with an acquired immunodeficiency syndrome (AIDS)-like illness, prior to identification of the human immunodeficiency virus (HIV). Since that time further sporadic cases of this invasive infection have been reported in HIV and AIDS. We present two further cases and also a review of the current literature.

THE MECHANISM OF FOLATE DEFICIENCY IN PSORIASIS

—Sixteen (27%) of 58 patients with psoriasis had low serum folate levels (<30 ng./ml.), 4 (7%) had subnormal red cell folate levels and 16 (27%) had hypersegmented polymorphs in the peripheral blood films. Folic acid absorption was normal in all 12 patients in whom it was tested. The folate concentrations in scale from psoriasis lesions, keratin from the uninvolved skin of psoriatic subjects, and in normal keratin from non-psoriatic subjects were 008, 0-32 and 014^g./G. respectively. The estimated folate loss in psoriatic scale was insufficient to account for folate deficiency. There was no correlation between the serum folate level and the duration or extent of clinical psoriasis. It therefore appears that the high incidence of mild folate deficiency in psoriasis is due to increased utilization of folate by the process and by clinically uninvolved psoriatic skin.

DRUG REACTIONS XXIII

Disturbances of hair growth by chemical agents are becoming increasingly common in medical practice. Certain drugs, e.g. antimitotic agents, interfere with hair growth in the anagen or proliferative phase, and alterations in the normal structure of the anagen root can be seen microscopically (Van Scott, 1958). The mode of action in the case of other drugs is uncertain, and a logical classification of drugs causing alopecia is therefore difficult.

DRUG REACTIONS XII Cutaneous Reactions to Anti-rehumatic Drugs

phosphamide which was discontinued in December on account of influenza. In January 1970 recurrence of severe itching and eczematous rash was treated with cyclophosphamide 300 mg. by mouth daily, which was discontinued in February on account of leucopenia and was followed in March by severe generalized alopecia. Comment.—In discussion it was suggested by Dr Ives and generally agreed that this was a case of actinic reticuloid. On questioning the patient later he was emphatic that his exacerbations had always occurred in the summer months. His age of 46 years is considerably younger than that of the published cases.

DRUG REACTIONS XX Cutaneous

Cutaneous Reactions to Anticonvulsants ThiB standard drugs used in the treatment of epilepsy include the derivatives of hydantoin, oxazolidine, and succinimide. Phenobarbitone and Primidone, which is chemically related to the barbiturates, are both very useful anticonvulsants. The cutaneous reactions to barbiturates have been fully discussed in a previous review (Almeyda and Levantine, 1972). Carbamazepine is mentioned because of its use in trigeminal neuralgia. Anticonvulsant drugs are taken regularly for a prolonged period, and should not be stopped until the patient has been free from convulsions for at least 2-3 years. In fact, many patients may have to receive therapy for life, so that it is important to recognize the various side efFects.

DRUG EEACTIONS XIII

Psychotropic drugs are those wlrich influence the higher functions of the hrain. They include tranquillizers, anti-depressants, psychotomimetics, amphetamines, caffeine, morphine and many other drugs. Tranquillizers comprise the phenothiazines, the rauwolfia alkaloids e.g. reserpine, and many compounds of miscellaneous structure e.g. chlordiazepoxide, diazepam, ineprobamate, haloperidol etc. Phenothiazines contain three major chemical svib-divisions; the diinethylamine series e.g. chlorpromazino and promazine, the piperidine series e.g. thioridazine and the piperazine series e.g. prochlorperazine. Anti-depressants comprise tho stimulants e.g. amphetamine; the monoamine oxidase inhibitors e.g. tranylcypromine, isocarhoxazid, iproniazid and phenelzine; the iniinodibenzyl derivatives e.g. imipramine, amitriptyline, and nortriptyline. In general and psychiat;ric practice these drugs are widely prescribed. In this country over 6 million prescriptions per year are written for chlordiazepoxide alone. This review will be restricted to the cutaneous reactions noted during the use of the iminodihenzyl derivative imipramine and chlordiazepoxide.